IN SITU AND IN VITRO IMMUNOLOCALIZATION OF OVIDUCTIN BINDING SITES ON HAMSTER UTERINE EPITHELIAL CELLS AND DETECTION OF A HAMSTER OVIDUCTIN HOMOLOGUE IN THE FEMALE RAT REPRODUCTIVE TRACT

Oviductin is an oviduct-specific and high-molecular-weight glycoprotein that has been suggested to play important roles in the early events of reproduction. The present study was undertaken to localize the oviductin binding sites in the uterine epithelial cells of the golden hamster (Mesocricetus auratus) both in situ and in vitro, and to detect a hamster oviductin homologue in the female rat reproductive tract. Immunohistochemical localization of oviductin in the hamster uterus revealed certain uterine epithelial cells reactive to the monoclonal anti-hamster oviductin antibody. In order to study the interaction between hamster oviductin and the endometrium in vitro, a method for culturing primary hamster uterine epithelial cells has been established and optimized. Study with confocal microscopy of the cell culture system showed a labeling pattern similar to what was observed using immunohistochemistry. Pre-embedding immunolabeling of cultured uterine epithelial cells also showed gold particles associated with the plasma membrane and microvilli. These results demonstrated that hamster oviductin can bind to the plasma membrane of certain hamster uterine epithelial cells, suggesting the presence of a putative oviductin receptor on the uterine epithelial cell surface. In the second part of the present study, using the monoclonal anti-hamster oviductin antibody that cross-reacts with the rat tissue, we have been able to detect an oviduct-specific glycoprotein, with a molecular weight of 180~300kDa, in the female rat reproductive tract. Immunohistochemical labeling of the female rat reproductive tract revealed a strong immunolabeling in the non-ciliated oviductal epithelial cells and a faint immunoreaction on the cell surface of some uterine epithelial cells. Ultrastructurally, immunogold labeling was restricted to the secretory granules, Golgi apparatus, and microvilli of the non-ciliated secretory cells of the oviduct. In the uterus, immunogold labeling was observed on the cell surface of some uterine epithelial cells. Furthermore, electron micrographs of ovulated oocytes showed an intense immunolabeling for rat oviductin within the perivitelline space surrounding the ovulated oocytes. The findings of the present study demonstrated that oviductin is present in the rat oviduct and uterus, and it appears that, in the rat, oviductin is secreted by the non-ciliated secretory cells of the oviduct.

RED COATS AND WILD BIRDS: MILITARY CULTURE AND ORNITHOLOGY ACROSS THE NINETEENTH-CENTURY BRITISH EMPIRE

“Red coats and wild birds: military culture and ornithology across the nineteenth-century British Empire” investigates the intersections between British military culture and the practices and ideas of ornithology, with a particular focus on the British Mediterranean. Considering that British officers often occupied several imperial sites over the course of their military careers, to what extent did their movements shape their ornithological knowledge and identities at “home” and abroad? How did British military naturalists perceive different local cultures (with different attitudes to hunting, birds, field science, etc.) and different local natures (different sets of birds and environments)? How can trans-imperial careers be written using not only textual sources (for example, biographies and personal correspondence) but also traces of material culture? In answering these questions, I centre my work on the Mediterranean region as a “colonial sea” in the production of hybrid identities and cultural practices, and the mingling of people, ideas, commodities, and migratory birds. I focus on the life geographies of four military officers: Thomas Wright Blakiston, Andrew Leith Adams, L. Howard Lloyd Irby, and Philip Savile Grey Reid. By the mid-nineteenth century, the Mediterranean region emerged as a crucial site for the security of the British “empire route” to India and South Asia, especially with the opening of the Suez Canal in 1869. Military stations served as trans-imperial sites, connecting Britain to India through the flow of military manpower, commodities, information, and bodily experiences across the empire. By using a “critical historical geopolitics of empire” to examine the material remnants of the “avian imperial archive,” I demonstrate how the practices and performances of British military field ornithology helped to: materialize the British Mediterranean as a moral “semi-tropical” place for the physical and cultural acclimatization of British officers en route to and from India; reinforce imperial presence in the region; and make “visible in new ways” the connectivity of North Africa to Europe through the geographical distribution of birds. I also highlight the ways in which the production of ornithological knowledge by army officers was entwined with forms of temperate martial masculinity.

The role of Schizosaccharomyces pombe Cdc2 phosphorylation sites on Cdc25 in mitotic timing

Cell size control and mitotic timing in Schizosaccharomyces pombe is coupled to the environment through several signal transduction pathways that include stress response, checkpoint and nutritional status impinging on Cdc25 tyrosine phosphatase and Wee1 tyrosine kinase. These in turn regulate Cdc2 (Cdk1) activity and through a double feedback loop, further activates Cdc25 on 12 possible phosphorylation sites as well as inhibiting Wee1. Phosphomutants of the T89 Cdc2 phosphorylation site on Cdc25, one with a glutamate substitution (T89E) which is known to phosphomimetically activate proteins and an alanine substitution (T89A), which is known to block phosphorylation, exhibit a small steady-state cell size (semi-wee phenotype), a known hallmark for aberrant mitotic control. To determine whether the T89 phosphorylation site plays an integral role in mitotic timing, the phosphomutants were subjected to nitrogen shifts to analyze their transient response in the context of nutritional control. Results for both up and downshifts were replicated for the T89E phosphomutant, however, for the T89A phosphomutant, only a nutritional downshift has been completed so far. We found that the steady-state cell size of both phosphomutants was significantly smaller than the wild-type and in the context of nutritional control. Furthermore, the constitutively activated T89E phosphomutant exhibits residual mitotic entry, whereas the wild-type undergoes a complete mitotic suppression with mitotic recovery also occurring earlier than the wild-type. In response to downshifts, both phosphomutants exhibited an identical response to the wild-type. Further characterization of the other Cdc2 phosphorylation sites on Cdc25 are required before conclusions can be drawn, however T89 remains a strong candidate for being important in activating Cdc25.