Exploration of Genes Associated with Sponge Silicon Biomineralization in the Whole Genome Sequence of the Hexactinellid Euplectella curvistellata.

Silicatein is the first protein isolated from the silicon biominerals and characterized as constituent of the axial filament in the silica spicules of the demosponge Tethya aurantia, by significant sequence similarity with cathepsin L, an animal lysosomal protease, and as a catalyst of silica polycondensation at neutral pH and room temperature. This protein was then identified in a wide range of the class Demospongiae and in some species of the class Hexactinellida. Our attempt to isolate silicatein from the silica skeleton of Euplectella was unsuccessful, but instead we discovered glassin, a protein directing acceleration of silica polycondensation and sharing no significant relationship with any proteins including silicatein. The present study aims to verify the existence of silicatein by exploring the whole genome DNA sequence database of E. curvistellata with the sequence similarity search. Although we identified the sequences of glassin, cathepsin L and chitin synthetase, an enzyme synthesizing chitin, which has already been found in the silicon biominerals in E. aspergillum, silicatein failed to be identified. Our result indicates that silicatein is not essential for poriferan silicon biomineralization in the presence of glassin

社会的排除が状態自尊感情および将来予測に及ぼす影響

The present study investigates the effect of ambiguous rejection(e.g., people are ignored by others)and obvious rejection(e.g., people are negatively evaluated by others)on predictions of future rejection. One hundred and thirty-seven male and female undergraduates were asked to imagine situations in which they were either accepted, rejected implicitly, or rejected explicitly, and to complete a questionnaire. The results suggest that social rejection lowered participants\u27 state self-esteem and boosted the perceived likelihood of future rejection by the rejecter. However, social rejection did not boost the perceived likelihood of future rejection by people they didn\u27t already know. Although there was no difference between ambiguous rejection and obvious rejection generally, males were less likely than females to lower their state self-esteem in cases of obvious rejection. The results are discussed from the perspective of sociometer theory

Silica-associated proteins from hexactinellid sponges support an alternative evolutionary scenario for biomineralization in Porifera

Source data for phylogenetic inference