Hirosaki University

Animals must avoid adhesion to objects in the environment to maintain their mobility and independence. The marine invertebrate chordate ascidians are characterized by an acellular matrix tunic enveloping their entire body for protection and swimming. The tunic of ascidian larvae consists of a surface cuticle layer and inner matrix layer. Hydrophilic substances coat the cuticle; this modification is thought to be for preventing adhesion. However, the molecule responsible for regulating this modification has not been clarified. We here found that the tunicate-specific protein Epi-1 is responsible for preventing adhesiveness of the tunic in the ascidian Ciona intestinalis Type A. Ciona mutants with homozygous knockouts of Epi-1 exhibited adhesion to plastic plates and to other individuals. The cuticle of the Epi-1 mutants was fragile, and it lost the glycosaminoglycans supplied by test cells, the accessory cells that normally attach to the tunic surface. Although it has an apparent signal peptide for membrane trafficking, we showed that the Epi-1 protein is localized to the cytosol of the epidermal cells. Our study suggests that the emergence of the tunicate-specific protein Epi-1 made the tunic less adhesive, providing a selective advantage for the last common tunicate ancestor.

We identified a novel mutant of Bombyx mori, designated as male-absent oily (genetic symbol: om). The larval integument of this mutant is translucent due to a lack of uric acid in the integument. This mutation is Z-linked, and as mutant females are infertile, it is impossible to obtain om homozygous males. Using positional cloning combined with RNA-seq analysis, we identified a 1-bp deletion in the B. mori peroxiredoxin 6 (BmPrx6) gene. CRISPR/Cas9 knockout of BmPrx6 resulted in a translucent larval integument, indicating BmPrx6 as the causative gene for the om locus. Xanthine dehydrogenase (XDH)/xanthine oxidase (XO) is a key enzyme for uric acid synthesis. Injection of bovine XO into om mutants rescued the translucent phenotype, indicating that om is a mutant with defective XDH activity. To investigate XDH in B. mori, we generated a FLAG-tagged XDH gene using the CRISPR/Cas9 knock-in approach. Western blot analysis of XDH in om mutants revealed that BmPrx6 is crucial for the posttranslational activation of XDH. The role of BmPrx6 in regulating XDH activity is discussed.

In this study, the possibility of obtaining a catalytic effect from the co-thermal processing of Napier Grass (NG) biochar with raw Giant Miscanthus (GM) was investigated.The NG whole plant (NGC), NG stem part (NGSC), and demineralized NG (DNGC) were used to prepare various biochar samples under four temperatures (NGC300, NGC400, NGC500, and NGC600), and then the steam co-gasification of NG-biochar and GM was performed.It is found that a higher gasification temperature and a higher biochar blending ratio resulted in higher synergy effect in syngas production, and in the best mixing ratio (1:2 biomass to biochar), a maximum of 110 mmol/g (daf) gas yield was achieved by combining GM and NGC500 at a temperature of 850 °C and a steam flow rate of 0.1 g/min while there was a 28 mmol/g-biomass (daf) yield with GM only.Here, we explored the relationship between biochar characterization and co-gasification performance by considering the transformation behavior of inherent K in NG biochar as a catalytic species.XRD anal. showed that crystallized K forms (KCl mainly) in biochar could be transformed into more fixed forms like KAlSi₃O₈, K₂SiO₃ and K₂SO₄ after the co-gasification process while the majority was volatilized.Based on the catalytic index (CI) of biochar, it is confirmed that the effect of K in NG-biochar is more prominent than those of other alkali metals like Na, Ca, and Fe.