Abstract not available

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Bibliography: leaves 169-205. This thesis suggests that the testicular macrophage exhibits characteristics similar to that of a suppressor macrophage phenotype. The inhibition of lymphocyte proliferation by the testicular macrophage, its unique cytokine profile, high basal production of GM-CSF and prostaglandins, and the refractoriness to LPS all suggests a role that contributes to the immune privilege that is afforded the testis. However, these aspects of testicular macrophage immuno-biology also support a role in local cell-cell communication and regulation of the normal physiology of the testis, and macrophages may be directly involved in Leydig cell steriogenesis.

NMES1 is a gene of unknown function first characterized in 2002. Reduction of the expression of this gene has been implicated in skin tumorigenesis in mice. Expression of NMES1 is observed in epithelial tissue but expression in the testis is significantly higher than in epidermis. Because stallion fertility is an economically important trait, we decided to characterize the NMES1 gene in stallions. We screened the CHORI241 library and obtained the full length equine NMES1 genomic sequence by direct sequencing off of clone CH241-11J8. In order to experimentally determine the 5’ and 3’ untranslated regions (UTRs) we conducted RLM-RACE experiments using stallion testis RNA. The equine NMES1 mRNA is 534 nt long and contains 5 exons. Fluorescence in situ hybridization mapped NMES1 to chromosome Eca1q23. In situ experiments to testis tissue sections were inconclusive and yielded no data confirming the physical expression pattern of NMES1 in stallion testis tissue. In order to determine the expression pattern of NMES1 mRNA we conducted qRT-PCR assays on a panel of stallion testis samples from horses with normal and abnormal fertility. We found that expression was variable among both groups, with significantly less expression in some individuals. We also conducted the qRT-PCR assay on a panel of five equine tissues and found that the expression of NMES1 was more than 100-fold greater in testis than in other tissues examined. miR-147b is a miRNA of unknown target found within the 3’ UTR of NMES1. We conducted a miRNA qRT-PCR assay to determine the expression levels in stallion testis samples from fertile and sub-fertile stallions. We observed similar expression among both groups and the ratio of mRNA to miRNA did not appear constant. We also investigated miR-147b expression in a panel of five equine tissues and found that equine spleen had more than 8-fold greater expression than testis.

Thesis (Ph. D.)--University of Glasgow, 2003. / Ph. D. thesis submitted to the Faculty of Veterinary Medicine, University of Glasgow, 2003. Includes bibliographical references. Electronic version also available via Glasgow University e-Theses service.

published_or_final_version / Zoology / Master / Master of Philosophy

published_or_final_version / Surgery / Master / Master of Philosophy

In dieser Studie wurde der Einfluss von anabol-androgenen Steroiden (AAS) wie Testosteron auf die Angiogenese im peripubertären Hengsthoden untersucht. Sieben von 14 Junghengsten erhielten Durateston® und wurden vier [n=3; Versuchsgruppe 1 (VG1)] bzw. zwölf [n=4; Versuchsgruppe 2 (VG2)] Wochen nach der letzten Applikation kastriert, während die übrigen sieben Tiere ohne eine Behandlung in dem gleichen Zeitraum kastriert wurden. Im Rahmen der morphometrischen Untersuchung konnte ein Anstieg der Volumendichte und der Numerischen Dichte bezüglich der Blutgefäße in der Versuchsgruppe festgestellt werden, während die Fläche der Blutgefäßanschnitte in den Kapillaren der Versuchsgruppe kleiner ist als bei den Tieren in der Kontrollgruppe. Die erhöhte Angiopietin2- und transforming growth factor alpha-Expression in der VG1 könnte möglicherweise für diese morphometrischen Be-funde verantwortlich sein. Die Blutgefäße der Versuchsgruppen zeigen, möglicherweise stimuliert durch Testoste-ron, eine höhere vascular endothelial growth factor-receptor2-Expression als die der Kontrollgruppe. Aufgrund der signifikanten Abnahme der morphometrischen Parameter von der VG1 zu der VG2 handelt es sich vermutlich um einen temporären Effekt.

Darbo tikslas: įvertinti imunokastracijos komerciniu preparatu Improvac® poveikį jauniems ir suaugusiems, lytiškai subrendusiems kuiliams. Darbo uždaviniai: 1. Įvertinti imunokastracijos poveikį jaunų kuilių augimo intensyvumui, priesvoriams ir mėsos kokybei. 2. Įvertinti imunokastracijos poveikį suaugusių / lytiškai subrendusių kuilių testosterono koncentracijai kraujyje, libido, spermos kokybei bei biocheminiams kraujo rodikliams. 3. Įvertinti imunokastracijos poveikį suaugusių / lytiškai subrendusių kuilių sėklidėms bei priedinėms lytinėms liaukoms. 4. Įvertinti imunokastracijos poveikį lytiškai subrendusių gyvulių mėsos kokybei bei indolo ir skatolo kiekiui skerdenoje. Mokslinis darbo naujumas ir reikšmė Suaugusių, lytiškai subrendusių ir jau naudojamų reprodukcijai kuilių imunokastracijai panaudotas komercinis preparatas Improvac®. Įvertintas dvigubos ir trigubos injekcijos poveikis gyvulių testosterono koncentracijai kraujyje, libido, spermos kokybei bei biocheminiams kraujo rodikliams, kuilių sėklidėms bei priedinėms lytinėms liaukoms, kuilio kvapą sudaran-čioms medžiagoms ir mėsos kokybei. Išvados: 1. Jaunų kuilių imunokastracija preparatu Improvac 95 ir 138 jų gyvavimo dienomis turėjo įtakos jų augimo intensyvumui, priesvoriams ir mėsos kokybei. Improvac grupės kuilių paros priesvoriai buvo 0,24±0,1 kg didesni, o skerdimo dieną jie vidutiniškai svėrė 2,02±3,93 kg daugiau nei chirurgiškai kastruoti kuiliai (p≤0,01). 2. Vakcinuotų gyvulių mėsa buvo liesesnė... [toliau žr. visą tekstą] / The aim of the study: To evaluate the impact of immunocastration by commercial product Improvac® on young and adults, sexually matured boars. The purpose of the study: 1. To evaluate the impact of immunocastration on intensity of grow, overweight and meat quality of young boars. 2. To evaluate the impact of immunocastration on testosterone concentration in blood, on libido, on semen’s quality and on biochemical indicators of adults/sexually matured boars. 3. To evaluate the impact of immunocastration on adults/sexually matured boar’s testicles and accessory sex glands. 4. To evaluate the impact of immunocastration on meat quality of sexually matured animals as well as on amount of indole and skatole in carcass. Conclusions: 1. Immunocastration of young boars with Improvac product on 95th and 138th day of life had an impact on growth intensity, overweight and meat quality. Day overweight of Improvac group boars were 0.24±0.1 kg bigger and on a day of slaughtering they weighted 2.02±3.93kg more in average if compare with surgically castrated boars (P≤0.01). 2. Meat of vaccinated animals was leaner, percentage of muscularity was bigger and carcass quality according to SEUROP classification was higher (P≤0.001), but for separate meat quality parameters immune-castration of boars had no influence (P≥0.05). During current research amounts of indole and skatole found in vaccinated animals‘ fat haven‘t exceed sensible and permissible limits. 3. Immunocastration of mature boars with... [to full text]

Abstract Biotechnological strategies aimed at producing male-only offspring have the potential to improve the yield of the Australian beef industry. As a proof-of-concept project, I aimed to target the primary male sex-determining gene Sry to the X chromosome in mice, to produce a transgenic XY male that would transmit Sry – and hence maleness – to both XX and XY offspring. In this project I aimed to target a 14.5 kb DNA fragment containing Sry to an X-chromosome locus that escapes X-inactivation. After considering many potential loci, a targeting strategy and construct were designed for the SMCX locus, which is well conserved between mouse, human and bovine. A targeting vector with 5kb and 3kb arms of homology was also constructed without Sry, to target the locus. Attempts to introduce the 14.5 kb Sry fragment into the construct were unsuccessful, and a smaller construct, containing only the coding sequence of the Sry gene driven by a strong promoter, is currently being made. In order to translate this transgenic approach into cattle, other facets of bovine sex determination required investigation. First, it was important to identify the necessary regulatory regions upstream of bovine SRY needed for the gene to be functional, and secondly to investigate the timing of testis development in male bovine embryos. To enable sequence comparison, I sequenced upstream of the bovine and goat SRY gene and through bioinformatic analysis identified regulatory regions common to several mammals. I identified four regions of high homology upstream of bovine SRY conserved between human, goat, and pig, but not mouse. These regions are likely to be important for the regulation of the gene in these species, as they share unique transcription factor binding sites. From this research I concluded that 9 kb upstream of bovine SRY were likely to be useful in transgenic strategies to produce sex-reversed cattle. Although I attempted to use a 15 kb bovine genomic fragment containing SRY to sex reverse XX mice, this project was unsuccessful. I also investigated the expression pattern of genes known to have a role in sex determination, including SRY, in early bovine embryos. I identified the major time points important for male sex determination, including the first appearance of the gonadal ridge from the mesonephros at day 31, the onset of SRY expression and its peak at day 39, and the appearance of testis cords at day 42, along with the pattern of expression of many other genes downstream of SRY. This information will allow future researchers to check that transgenic SRY expression is occurring at the correct time and place for it to be able to cause XX sex reversal in cattle. I also identified some of the major time points important for female sex determination, including that ovigerous cords form between CRL 37-91 in female bovine embryos. In addition I show the cellular differentiation of the cortex and medulla at this time. I have also predicted the female germ cell entry into meiosis around CRL 40 in bovine embryos through the use of qRT-PCR for STRA8 and SYCP3. This is the first detailed account of gene expression profiles in early female bovine embryos, unfortunately the data is incomplete due to an uneven distribution of embryo ages due to the difficulty of obtaining embryos from timed matings. Hopefully in the future obtaining more female embryos of the missing stages can complete the female data. This project has provided additional basic knowledge about bovine sex-determination events to ensure the possibility of making single-sex livestock a real possibility in the future. The similarity between human and bovine developmental time frames also points to cattle being a good alternative model for human development, and emphasises the need for further research in species other than mouse, with the aim of ultimately understanding our own biology.