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.

A Comparison of the Impacts of Lithium Extraction and Lithium Recycling Processes

Lithium is used in the cathode and electrolyte of rechargeable batteries in many portable electronics and electric vehicles, and is thus seen as a critical component of modern technology (Gruber et al., 2011). Electric vehicles are promoted as a way to reduce carbon emissions associated with the transportation sector, which accounts for 14.3% of anthropogenic greenhouse gas emissions (OECD International Transport Forum, 2010). However, the sustainability of lithium procurement will influence the overall environmental impact of this proposed “green” solution. It is estimated that 66% of the world’s lithium resource is contained in natural brines, 24% in pegmatites, and 8% in sedimentary rocks such as hectorite clays (Gruber et al., 2011). It has been shown that “[r]ecycling of lithium from Li-ion batteries may be a critical factor in balancing the supply of lithium with future demand” (Gruber et al., 2011). In an attempt to quantify energy and materials consumption associated with production of a unit of useful lithium compounds, industry reports and peer-reviewed scientific literature concerning lithium mining and lithium recycling were reviewed and compared. Other aspects of sustainability, such as waste or by-products produced in the production of a unit of useful lithium, were also explored. Thus, this paper will serve to further the evaluation of the comparative environmental consequences associated with lithium production via extraction versus recycling. Efficiencies must be made in both processes to maximize productivity while minimizing ecological harm.