Nitric oxide synthase during early embryonic development in silkworm Bombyx mori: Gene expression, enzyme activity, and tissue distribution

Molecular Characterization and Tissue Distribution of Calcineurin Regulatory B Subunit during the Prevention of Diapause in the Silkworm, Bombyx mori

To clarify the molecular mechanism of prevention of entry into diapause in Bombyx mori by HCl treatment, we biochemically analyzed calcineurin regulatory B subunit (CNB) in diapause eggs treated with HCl solution. Our previous studies revealed that HCl treatment causes Ca²⁺ to efflux from diapause eggs. Therefore, we attempted to analyze CNB, which is known to associate with Ca²⁺. The gene expression level of CNB was increased by HCl treatment and the changes of the gene expression were almost the same as that in the non-diapause eggs. As for diapause eggs, almost no gene expression of CNB was confirmed except just after oviposition. In the assay for phosphorylation by protein kinase CK2, recombinant CNB (rCNB) was phosphorylated in vitro. Additionally, a Ca²⁺ binding assay indicated that rCNB shows affinity for Ca²⁺. The distribution of CNB was investigated with an immunohistochemical technique using antiserum against rCNB in diapause eggs and HCl-treated diapause eggs. CNB was localized in serosa cells and yolk cells in both eggs. These data may suggest that CNB is activated by intracellular Ca²⁺ or efflux Ca²⁺ resulting from HCl treatment, and that it plays a role in the molecular mechanisms of artificial diapause prevention or the breaking of diapause in the silkworm.

Integrative transcriptome, proteome, and microRNA analysis reveals the effects of nitrogen sufficiency and deficiency conditions on theanine metabolism in the tea plant (Camellia sinensis)

Nitrogen (N) is associated with amino acid metabolism in higher plants. Theanine is an important amino acid in tea plants. To explore the relationship between theanine metabolism and N conditions, we examined the differentially expressed genes (DEGs), proteins (DEPs), and microRNAs (DEMs) involved in theanine metabolism in tea plant shoots and roots under N sufficiency and deficiency conditions. Transcriptome, proteome, and microRNA analyses were performed on tea plant shoots and roots under N sufficiency and deficiency conditions. The contents of theanine, expression levels of genes involved in theanine metabolism, contents of proteinogenic amino acids, and activity of enzymes were analyzed. The DEP-DEG correlation pairs and negative DEM-DEG interactions related to theanine metabolism were identified based on correlation analyses. The expression profiles of DEGs and negative DEM-DEG pairs related to theanine biosynthesis were consistent with the sequencing results. Our results suggest that the molecular and physiological mechanism of theanine accumulation is significantly affected by N sufficiency and deficiency conditions. The DEGs, DEPs, and DEMs and the activity of the enzymes involved in theanine biosynthesis might play vital roles in theanine accumulation under N sufficiency and deficiency conditions in the shoots and roots of tea plants.