Mechanisms for the uptake and transport of carotenoids, essential nutrients for humans, are not well understood in any animal system. The Y (Yellow blood) gene, a critical cocoon color determinant in the silkworm Bombyx mori, controls the uptake of carotenoids into the intestinal mucosa and the silk gland. Here we provide evidence that the Y gene corresponds to the intracellular carotenoid-binding protein (CBP) gene. In the Y recessive strain, the absence of an exon, likely due to an incorrect mRNA splicing caused by a transposon-associated genomic deletion, generates a nonfunctional CBP mRNA, resulting in colorless hemolymph and white cocoons. Enhancement of carotenoid uptake and coloration of the white cocoon was achieved by germ-line transformation with the CBP gene. This study demonstrates the existence of a genetically facilitated intracellular process beyond passive diffusion for carotenoid uptake in the animal phyla, and paves the way for modulating silk color and lipid content through genetic engineering.carotenoid transport ͉ cocoon color ͉ transgenic silkworm

The carotenoid-binding protein (CBP) of the domesticated silkworm, Bombyx mori, a major determinant of cocoon color, is likely to have been substantially influenced by domestication of this species. We analyzed the structure of the CBP gene in multiple strains of B. mori, in multiple individuals of the wild silkworm, B. mandarina (the putative wild ancestor of B. mori), and in a number of other lepidopterans. We found the CBP gene copy number in genomic DNA to vary widely among B. mori strains, ranging from 1 to 20. The copies of CBP are of several types, based on the presence of a retrotransposon or partial deletion of the coding sequence. In contrast to B. mori, B. mandarina was found to possess a single copy of CBP without the retrotransposon insertion, regardless of habitat. Several other lepidopterans were found to contain sequences homologous to CBP, revealing that this gene is evolutionarily conserved in the lepidopteran lineage. Thus, domestication can generate significant diversity of gene copy number and structure over a relatively short evolutionary time.

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A Facile and Practical Synthesis of Nicolaou's Key Intermediates, 2-Methyl-and 2,6-Dimethyltetrahydropyrans, Toward the Total Synthesis of Ladder-Shaped Polyethers. -A rapid access to tetrahydropyrans (I) in only seven and eight steps starting from 2-deoxy-D-ribose is described. -(NAKASHIMA, T.; BABA, T.; ONOUE, H.; YAMASHITA, W.; TORIKAI*, K.; Synthesis 45 (2013) 17, 2417-2425, http://dx.doi.org/10.1055/s-0033-1338503 ; Dep. Chem., Grad. Sch. Sci., Kyushu Univ., Higashi, Fukuoka 812, Japan; Eng.) -Mais 05-157

A facile and robust method to prepare 2-methyl-and 2,6-dimethyltetrahydropyrans, most useful Nicolaou intermediates for the synthesis of ladder-shaped polyethers, is disclosed. The established highly practical recipe, adopting chemo-and stereoselective catalytic oxidations and one-pot reactions with few chromatographic purifications, would significantly facilitate the large-scale supply of pivotal monocyclic building blocks, which is a rate-determining process of gigantic tetrahydropyran-containing natural products synthesis.