Phenylthiourea Specifically Reduces Zebrafish Eye Size

Phenylthiourea (PTU) is commonly used for inhibiting melanization of zebrafish embryos. In this study, the standard treatment with 0.2 mM PTU was demonstrated to specifically reduce eye size in larval fish starting at three days post-fertilization. This effect is likely the result of a reduction in retinal and lens size of PTU-treated eyes and is not related to melanization inhibition. This is because the eye size of tyr, a genetic mutant of tyrosinase whose activity is inhibited in PTU treatment, was not reduced. As PTU contains a thiocarbamide group which is presented in many goitrogens, suppressing thyroid hormone production is a possible mechanism by which PTU treatment may reduce eye size. Despite the fact that thyroxine level was found to be reduced in PTU-treated larvae, thyroid hormone supplements did not rescue the eye size reduction. Instead, treating embryos with six goitrogens, including inhibitors of thyroid peroxidase (TPO) and sodium-iodide symporter (NIS), suggested an alternative possibility. Specifically, three TPO inhibitors, including those that do not possess thiocarbamide, specifically reduced eye size; whereas none of the NIS inhibitors could elicit this effect. These observations indicate that TPO inhibition rather than a general suppression of thyroid hormone synthesis is likely the underlying cause of PTU-induced eye size reduction. Furthermore, the tissue-specific effect of PTU treatment might be mediated by an eye-specific TPO expression. Compared with treatment with other tyrosinase inhibitors or bleaching to remove melanization, PTU treatment remains the most effective approach. Thus, one should use caution when interpreting results that are obtained from PTU-treated embryos

Threads of memory: Reproducing the cypress tree through sensual consumption

This paper is concerned with the ways in which a group of Persian women, who have all fled Iran in the last two decades, give meaning to place and memory through the everyday practices of cooking and embroidery. While there are many different localised arts of patterning and flavour, we focus here on the recurring pattern of bota (the Cypress tree). In particular, we examine how the bota motif links both the making of domestic sweets and cloths, and is central in recalling and remaking a sense of place. The Cypress tree symbolises life: the continuation of life in place, and the continuation of place in life. In creating and consuming the bota motif, through eating, laying tablecloths, wrapping towels, sitting on cushions and drawing curtains, embodied experiences of landscape and relationships are reproduced. The embroidery items entail and occasion sensual engagement in and of themselves, and also serve as backgrounds for specific sensual engagements, including, for example, as tablecloths upon which food will be served. Engagement with the bota pattern cannot be characterised along strictly divided sensual dimensions. Rather, we argue that the senses are intertwined in a synaesthetic knot in which memory is embodied and reproduced