Occurrence of xanthommatin containing pigment granules in the epidermal cells of the silkworm, Bombyx mori

Sawada, Hiroshi; Tsusué, Motoo; Yamamoto, Takayuki; Sakurai, Shunsuke

doi:10.1016/0020-1790(90)90096-d

Cited by 16 publications

(14 citation statements)

References 16 publications

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“…This purification protocol produces ommochromasome fractions that are suitable for performing cryo‐EM, thus enabling characterisation of ommochromasome ultrastructure in detail. Other ultracentrifugation methods used to extract ommochromasomes from other tissues and organisms tend to be based on sucrose‐only gradients or slow centrifugation, and might either lead to contaminated preparations (Sawada et al, ; Sawada, ) and/or be only suitable for ommochromasomes of lower relative density, for example in squid (DiBona et al, ).…”

Section: Ommochromes Within the Cell: The Ommochromasome Life Cyclementioning

confidence: 99%

Ommochromes in invertebrates: biochemistry and cell biology

2018

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Ommochromes are widely occurring coloured molecules of invertebrates, arising from tryptophan catabolism through the so-called Tryptophan → Ommochrome pathway. They are mainly known to mediate compound eye vision, as well as reversible and irreversible colour patterning. Ommochromes might also be involved in cell homeostasis by detoxifying free tryptophan and buffering oxidative stress. These biological functions are directly linked to their unique chromophore, the phenoxazine/phenothiazine system. The most recent reviews on ommochrome biochemistry were published more than 30 years ago, since when new results on the enzymes of the ommochrome pathway, on ommochrome photochemistry as well as on their antiradical capacities have been obtained. Ommochromasomes are the organelles where ommochromes are synthesised and stored. Hence, they play an important role in mediating ommochrome functions. Ommochromasomes are part of the lysosome-related organelles (LROs) family, which includes other pigmented organelles such as vertebrate melanosomes. Ommochromasomes are unique because they are the only LRO for which a recycling process during reversible colour change has been described. Herein, we provide an update on ommochrome biochemistry, photoreactivity and antiradical capacities to explain their diversity and behaviour both in vivo and in vitro. We also highlight new biochemical techniques, such as quantum chemistry, metabolomics and crystallography, which could lead to major advances in their chemical and functional characterisation. We then focus on ommochromasome structure and formation by drawing parallels with the well-characterised melanosomes of vertebrates. The biochemical, genetic, cellular and microscopic tools that have been applied to melanosomes should provide important information on the ommochromasome life cycle. We propose LRO-based models for ommochromasome biogenesis and recycling that could be tested in the future. Using the context of insect compound eyes, we finally emphasise the importance of an integrated approach in understanding the biological functions of ommochromes.

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Section: Ommochromes Within the Cell: The Ommochromasome Life Cyclementioning

confidence: 99%

Ommochromes in invertebrates: biochemistry and cell biology

2018

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“…Currently its genetic linkage map contains more than 200 markers on 28 linkage groups and covers nearly 1000 centimorgans (cM) (Doira, 1992). Most of these markers are morphological or physiological mutations affecting such fundamental processes as egg formation (e.g., see Kawaguchi & Doira, 1973;Kawaguchi et al 1983Kawaguchi et al , 1987Kawaguchi et al , 1988Kawaguchi et al , 1990Kawaguchi et al , 1993Fujikawa et al 1993) and choriogenesis (Nadel et al 1980 a, b;Gautreau et al 1993), embryonic patterning and segment identity (e.g., see Tazima, 1964;Ueno et al 1992Ueno et al , 1995, larval epidermal pigmentation (e.g., see Tamura, 1977Tamura, ,1983Tamura & Akai, 1990;Sakurai & Tsujita, 1976 a, b;Sawada et al 1990;Shimizu et al 1993), hormone action (Shimizu et al 1980;Nagata et al 1992), and diapause (Yamamoto et al 1978;Sonobe et al 1986) (see also Doira, 1978;Goldsmith, 1995). About 20 loci encode identified gene products such as isozymes, hemolymph, silk, and chorion proteins which were mapped using electrophoretic variants, or more recently, cloned neuropeptides localized via the polymerase chain reaction (Shimada et al 1994;Pinyarat et al 1995).…”

Section: Introductionmentioning

confidence: 98%

A genetic linkage map for the domesticated silkworm,Bombyx mori, based on restriction fragment length polymorphisms

1995

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We present data for the initial construction of a molecular linkage map for the domesticated silkworm, Bombyx mori, based on 52 progeny from an F2 cross from a pair mating of inbred strains p50 and C108, using restriction fragment length polymorphisms (RFLPs). The map contains 15 characterized single copy sequences, 36 anonymous sequences derived from a follicular cDNA library, and 10 loci corresponding to a low copy number retrotransposon, mag. The 15 linkage groups and 8 ungrouped loci account for 23 of the 28 chromosomes and span a total recombination length of 413 cM; 10 linkage groups were correlated with established classic genetic maps. Scoring data from Southern blots were analysed using two Pascal programs written specifically to analyse linkage data in Lepidoptera, where females are the heterogametic sex and have achiasmatic meiosis (no crossing-over). These first examine evidence for linkage by calculating the maximum lod score under the hypothesis that the two loci are linked over the likelihood under the hypothesis that the two loci assort independently, and then determine multilocus linkage maps for groups of putatively syntenic loci by calculating the maximum likelihood estimate of the recombination fractions and the log likelihood using the EM algorithm for a specified order of loci along the chromosome. In addition, the possibility of spurious linkage was exhaustively tested by searching for genotypes forbidden by the absence of crossing-over in one sex.

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“…Our recent study lends support to his postulate. Epidermal cells of the silkworm mutant quail contain a new type of electron dense pigment granule in which xanthommatin was localized binding to protein (19).…”

Section: Introductionmentioning

confidence: 99%

Localization of Sepiapterin Deaminase and Pteridines In the Granules In Epidermal Cells of the Silkworm, Bombyx mori

1990

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SummaryA new method for assay of sepiapterin deaminase (3.5.4.24) activity by use of high performance liquid chromatography (HPLC) was developed. By this sensitive method the enzyme activity in the cell organelle was assayed. After cell fractionation, the enzyme was extracted with deoxycholate from pteridine granules of epidermal cells of the lemon mutant silkworm. On stepwise sucrose gradient centrifugation, most of the enzyme activity localized in the aggregated pteridine granules fraction, while the soluble fraction contained only one fourth of the total enzyme activity. The enzyme in the granule fraction had the same properties as the previously reported sepiapterin deaminase. These data show that the enzyme is localized in pteridine granules in the living cells. The attachment of the enzyme to the granule membrane is rather loose and previous papers studied the enzyme released from the granules.Cell fractionation and morphological observation showed that sepiapterin, sepialumazine and other pteridines were also localized in the granules together with uric acid.

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Occurrence of xanthommatin containing pigment granules in the epidermal cells of the silkworm, Bombyx mori

Cited by 16 publications

References 16 publications

Ommochromes in invertebrates: biochemistry and cell biology

Ommochromes in invertebrates: biochemistry and cell biology

A genetic linkage map for the domesticated silkworm,Bombyx mori, based on restriction fragment length polymorphisms

Localization of Sepiapterin Deaminase and Pteridines In the Granules In Epidermal Cells of the Silkworm, Bombyx mori

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