[Truncated abstract] Intracellular communication between osteoclasts and osteoblasts is imperative to maintain bone integrity. A myriad of molecules are responsible for regulating osteoblast and osteoclast activity. In particular, it is well documented that osteoblast-derived factors are crucial in directly controlling osteoclast formation and function. Since bone formation is coupled to bone resorption, it would be expected that osteoclasts also have some role in regulating the growth and function of osteoblast cells. However, despite extensive research upon osteoclast and osteoblast biology, the mechanisms by which osteoclasts regulate osteoblast growth and function is not well understood. In an attempt to further elucidate the mechanisms by which osteoclasts and osteoblasts communicate, the technique of subtractive hybridisation was used to identify a novel osteoclastderived factor identical to that of mouse Seminal Vesicle Secretion VII (SVS VII). Previous characterisation of the gene in bone demonstrated that SVS VII was abundantly and specifically expressed by mature osteoclasts (Phan, 2004). Additional research hinted that SVS VII acted as a novel osteoclast-derived factor, that by paracrine mechanisms, targeted osteoblast function (Phan, 2004). However, it remained open as to whether the SVS VII molecule did uniquely target the osteoblast, and whether this interaction influenced bone formation in vivo. Therefore, this thesis endeavoured to functionally characterise the role of the SVS VII molecule in the bone environment. ... Further work is needed to identigy a clear consensus binding sequence, to determine the specificity of the interaction between SVS VII protein and each phage clone, and to isolate a specific binding partner for SVS VII. In conclusion, the studies of this thesis sought to characterise the significance of SVS VII expression by mature osteoclasts, relative to its effects on osteoblast behaviour, but failed to conclusively determine a role for SVS VII in bone. Given that the effects of SVS VII on in vitro osteoblast activity and function are minimal, it is doubtful that SVS VII primarily acts as a paracrine factor integral to osteoblast function. Therefore, these findings conflict with those presented previously (Phan, 2004). However, it was demonstrated that SVS VII treatment was associated with in vivo effect on the skeleton, suggesting that SVS VII may target other elements of the bone microenvironment. Via mechanisms not yet understood, which possibly involves additional factors of the bone 11 extracellular matrix, SVS VII may target a subset of osteoprogenitor cells within the bone environment and act to regulate their proliferation. Therefore, SVS VII may enhance osteogenic precursor cell number at sites of bone formation which would increase the pool of cells that can differentiate down the osteoblast linage and contribute to bone formation. In this regard, SVS VII might function in a manner homologous to the Ly-6 molecule Sca-1 and act as an important factor that maintains a balance between the bone formation and resorption process. Clearly, more work focusing on alternative facets of bone biology is needed to identify whether there is a significant role for SVS VII in skeletal tissue.

Submitted by Adriana Martinez (amartinez@unoeste.br) on 2017-08-31T20:12:04Z No. of bitstreams: 1 João Marcelo Martins Coluna.pdf: 316916 bytes, checksum: e3ff1f0c4795f8a26f2d99c916a84f41 (MD5) / Made available in DSpace on 2017-08-31T20:12:04Z (GMT). No. of bitstreams: 1 João Marcelo Martins Coluna.pdf: 316916 bytes, checksum: e3ff1f0c4795f8a26f2d99c916a84f41 (MD5) Previous issue date: 2014-03-24 / The aim of this study was to evaluate the effect of probiotics on the toxicity of increasing doses of potassium dichromate on the reproductive tract and adrenal glands of rats . Material and Methods: During a trial period of 90 days , we used 80 Wistar rats were divided randomly into 8 groups of 10 animals : GC (control ) , G1 (12 mg.kg - 1 K2Cr2O7 ) ; G24 ( 24 mg.kg - 1 K2Cr2O7 ) ; G36 ( 36 mg.kg - 1 K2Cr2O7 ) ; GP Control ( 0.2% probiotic ); G12P ( 12 mg.kg - 1 K2Cr2O7 + Probiotic 0.2 % ) ; G24P ( 24 mg.kg - 1 K2Cr2O7 + Probiotic 0.2 % ) ; G36P ( 36 mg.kg - 1 K2Cr2O7 Probiotic + 0.2% ) . Subsequently , weighing and histological evaluation of the reproductive organs and adrenal glands was performed , and plasma testosterone dosage . Results: Testes were heavier in group 7 There were statistical differences between the weights of the seminal vesicles only in groups 2:07 Histologically observed development of atypical hyperplasia and squamous metaplasia in the testes and seminal vesicles and degeneration of the germinal epithelium and tubular contraction testes despite the use of probiotics. Conclusion : The use of probiotics has not protected the epithelium of the reproductive system in this study . / O objetivo deste estudo foi avaliar o efeito do probiótico sobre a toxicidade de doses crescentes de dicromato de potássio sobre o trato reprodutivo e glândulas adrenais de ratos Wistar. Material e Métodos: Durante um período experimental de 90 dia, utilizou-se 80 ratos Wistar distribuídos aleatoriamente em 8 grupos de 10 animais: GC (controle), G12 (12 mg.kg-1 K2Cr2O7); G24 (24 mg.kg-1 K2Cr2O7); G36 (36 mg.kg-1 K2Cr2O7); GP (Controle, 0,2% probiótico); G12P (12 mg.kg-1 K2Cr2O7 + 0,2% Probiótico); G24P (24 mg.kg-1 K2Cr2O7 + 0,2% Probiótico); G36P (36 mg.kg-1 K2Cr2O7 + 0,2% Probiótico). Posteriormente foi realizada, pesagem e avaliação histológica dos órgãos reprodutivos e das glândulas adrenais, bem como dosagem de testosterona plasmática. Resultados: Os testículos pesaram mais no grupo 7. Houve diferença estatística entre os pesos das vesículas seminais somente nos grupos 2 e 7. Histologicamente observou-se desenvolvimento de hiperplasia atípica e metaplasia escamosa nos testículos e vesículas seminais e degeneração do epitélio germinativo e contração tubular nos testículos apesar do uso de probióticos. Conclusão: O uso de probiótico não protegeu o epitélio do sistema reprodutivo nesse estudo.

Sperm competition is a widely-recognized and powerful selective force. Male accessory glands are organs found across animal taxa that can influence sperm performance, and thus may be selected for in competitive contexts. In fishes, these organs are in fact rare, but display great diversity in form and function across species. Although the accessory gland is known to play a role in mate attraction, parental care, fertilization, or post-copulatory competition in a few select species, the role of this organ remains a mystery in most species. Many fishes with accessory glands also exhibit alternative reproductive tactics (ARTs), which add an extra layer of complexity to how species respond to sperm competition. Because males of different ARTs typically experience different levels of sperm competition risk, it’s possible they may differentially invest in accessory glands to overcome this competition. In this thesis, I used the plainfin midshipman fish (Porichthys notatus), a species with both ARTs and an accessory gland, to experimentally investigate the role of the accessory gland in sperm competition and uncover how this organ may differ between ARTs. Over a two-year period, I studied tactic-specific investment in the accessory gland in fish from the beaches of British Columbia. I also examined the effects of seminal fluid, produced in part by the accessory gland, on sperm performance and morphology. I found that males adopting the ‘guarder’ male tactic invested more in one region (the lobules) of this organ, while males adopting the smaller ‘sneaker’ male tactic invested more the other region of the gland (the nodes). Using data collected over five years, I found that guarder males also invested more in their whole accessory glands. Additionally, I report that sperm swam faster in the presence of seminal fluid, and seminal fluid increased sperm head size in both male tactics and increased midpiece size in guarder males. These results suggest that the plainfin midshipman accessory gland may have dual functions, one of which may be to aid sperm competitive ability through enhancements in swimming speed and potentially more successful sperm morphology. Taken together, the results of my thesis improve our knowledge of the role of non-sperm components like seminal fluid and the accessory gland in sperm competition, and demonstrate how species with ARTs can have varying physiological responses to such competition. Only a handful of studies have considered the effects of seminal fluid on sperm performance. By examining sperm competition in a more biologically relevant way and incorporating the effects of a little-studied organ that impacts sperm competition, we should be able to more generally and accurately appreciate the dynamics of post-copulatory competition and fertilization. / Thesis / Master of Science (MSc)