Unusual development of light-reflecting pigment cells in intact and regenerating tail in the periodic albino mutant of Xenopus laevis

Unusual light-reflecting pigment cells, “white pigment cells”, specifically appear in the periodic albino mutant (ap/ap) of Xenopus laevis and localize in the same place where melanophores normally differentiate in the wild-type. The mechanism responsible for the development of unusual pigment cells is unclear. In this study, white pigment cells in the periodic albino were compared with melanophores in the wild-type, using a cell culture system and a tail-regenerating system. Observations of both intact and cultured cells demonstrate that white pigment cells are unique in (1) showing characteristics of melanophore precursors at various stages of development, (2) accumulating reflecting platelets characteristic of iridophores, and (3) exhibiting pigment dispersion in response to α-melanocyte stimulating hormone (α-MSH) in the same way that melanophores do. When a tadpole tail is amputated, a functionally competent new tail is regenerated. White pigment cells appear in the mutant regenerating tail, whereas melanophores differentiate in the wild-type regenerating tail. White pigment cells in the mutant regenerating tail are essentially similar to melanophores in the wild-type regenerating tail with respect to their localization, number, and response to α-MSH. In addition to white pigment cells, iridophores which are never present in the intact tadpole tail appear specifically in the somites near the amputation level in the mutant regenerating tail. Iridophores are distinct from white pigment cells in size, shape, blue light-induced fluorescence, and response to α-MSH. These findings strongly suggest that white pigment cells in the mutant arise from melanophore precursors and accumulate reflecting platelets characteristic of iridophores

Assimilation—On (Not) Turning White: Memory and the Narration of the Postwar History of Japanese Canadians in Southern Alberta

This essay explores understandings of “race” – specifically, what it means to be Japanese – of nisei (“second generation”) individuals who acknowledge their near complete assimilation structurally and normatively into the Canadian mainstream. In historically-contextualized analyses of memory fragments from oral-history interviews conducted between 2011-2017, it focusses on voices and experiences of southern Alberta, an area whose significance to local, national, continental, and trans-Pacific histories of people of Japanese descent is belied by a lack of dedicated scholarly attention. In this light, this essay reveals how the fact of being Japanese in the latter half of the twentieth century was strategically central to nisei lives as individuals and in their communities. In imagining a racial hierarchy whose apex they knew they could never share with the hakujin (whites), the racial heritage they nevertheless inherited and would bequeath could be so potent as to reverse the direction of the colonial gaze with empowering effects in individual engagements then and as remembered now. We see how the narration and validation of one’s life is the navigation of wider historical contexts, the shaping of the post-colonial legacy of Imperial cultures, as Britain and Japan withdrew from their erstwhile colonial projects in Canada