科研之友
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摘要
Background. Biomineralization, e.g., in sea urchins or mollusks, includes the assembly of mesoscoPic suPerstructures from inorganic crystalline components and biopolymers" The resulting mesocrystals inspire biophysicists and material scientists alike, because of their extraordinary physical properties. Current efforts to replicate mesocrystal synthesis in vitro require understanding the princiPles of their self-assembly in vivo. One question, not addressed so far, is whether intracellular crystals of proteins can assemble with biopolymers into functional mesocrystal-like structures. During our electron microscopy studies into Arternia franciscarta (Crustacea: Branchiopoda), we found initial evidence of such proteinaceous mesostructures. Results. EM preparations with high-pressure freezing and accelerated freeze substitu tion revealed an extraordinary intracellular source of mesostructured inclusions in both the cyto -and nucleoplasm of the epidermal lining of ovisacs of A. franciscano. Confocal reflection microscopy not only confirmed our finding,. it also revealed reflective, light dispersing activity, of these flake-like structures, their positioning and orientation with respect to the ovisac inside. Both the striation of alternating electron dense and electronlucent components and the sharp edges of the flakes indicate self assembly of material of yet unlmown origin tinder supposed participation of crystallization. However, selected area electron diffraction could not v in the status of crystallization. Energy dispersive X-ray analysis measured a marked increase in nitrogen within the flake-like inclusion, and the almost complete absence of elements that,that are typically involved in inorganic crystallization. This rise in nitrogen could possibility be related to higher package density of Proteins, achieved by mesostructure assembly Conclusions. The ovisaclining of A franciscana is endowed with numerous mesas that not be tured inclusions, been previously hypothesize that their reported. We self-assembly was from proteinaceous polycrystalline funits and carbohydrate,. These mesas, mesostructured flakes displayed active optical er les prop, as an umbrella like, re flective cover of thefunctionalrole in the reproduction of ovisac, which suggests a A. franciscano. In turn, studies into ovisac mesostructured inclusions could help to optimizing rearing Arrenito as feed for fish farming. We propose Artemia ovisacs as an in vivo model system for studying mesostructure formation.
- 出版日期2017-10-27
