Tomoko Seyama

Butanol production from alkali-pretreated rice straw by co-culture of Clostridium thermocellum and Clostridium saccharoperbutylacetonicum.

The co-culture of cellulolytic Clostridium thermocellum NBRC 103400 and butanol-producing Clostridium saccharoperbutylacetonicum strain N1-4 produced 5.5 g/L of butanol from 40 g/L of delignified rice straw pretreated with 1% (wt/vol) NaOH. The addition of cellulase (100 U/g biomass) in a co-culture system significantly increased butanol production to 6.9 g/L using 40 g/L of delignified rice straw. Compared to the control, this increase in butanol production was attributed to the enhancement of exoglucanase activity on lignocellulose degradation in experimental samples. The results showed that the co-culture system in conjunction with enhanced exoglucanase activity resulted in cost-effective butanol production from delignified rice straw.

Three-dimensional culture of epidermal cells on ordered cellulose scaffolds

An ordered cellulose film scaffold, termed a nematic ordered cellulose (NOC) template, had unique surface properties and successfully induced the establishment of a three-dimensional (3D), hierarchical structure of epidermal cells by cell attachment and subsequent culture. Initially, the scaffold surface properties were characterized through contact angle measurements and atomic force microscopy to evaluate appropriate hydrophobicity and orientation of molecular chains for 3D culture. The template surfaces exhibited higher hydrophobicity, in the range of 70-75°, than usual cellulose films and appeared suitable for surface cell adhesion. In fact, epidermal cells successfully attached and proliferated favorably on the NOC templates, similar to development in normal culture flasks. Furthermore, the NOC film, as a semipermeable template, was also employed to allow 3D proliferation of epidermal cell layers in the perpendicular direction. The template proved to be suitable as a 3D cell culture device, resulting in the proposal that the construction processes of these 3D cell layers followed the basic concept of skin formation.

Secretion of a bundle of (1→3)-β-glucan hollow fibrils from protoplasts of callus suspension under a Ca2+-rich and acidic stressed condition

Abstract A fiber bundle composed of hollow fibrils is secreted from protoplasts of white birch (Betula phatyphylla Sukatcher var. japonica Kan No. 8) leaves callus and the secretion is more efficient in an acidic medium containing high concentration of Ca2+. The influence of the Ca2+ concentration and pH has been investigated concerning the number of cells secreted. The secreted hollow fibers were very thin. The 13C nuclear magnetic resonance spectra indicated that the fibers are composed of linear (1→3)-β-glucan without branches (callose). The potential utilization of such unique callose fibers and their optimized production needs more investigation.

Morphological responses of Betula protoplasts in fiber spinning

Abstract In a previous article, it was reported that, under stress conditions caused by Ca2+ ions, isolated protoplasts of Betula platyphylla leaves release a bundle of hollow fibrils as a stress-induced response. In the present article, details of this phenomenon have been investigated. As a special method, light microscopy combined with a ‘through focus variation’ technique was applied. In a regular culture medium, protoplasts could regenerate the cell walls, whereas protoplasts submitted to Ca2+ stress could not. Under stress conditions, the protoplasts inflated and formed a huge vacuole and, after 28 days, secreted the peculiar gigantic fibril with a diameter of 150 μm. The giant fibril is composed of (1→3)-β-glucan chains, i.e., the material of callose tissue.

Spinning of a gigantic bundle of hollow fibrils by a spirally moving higher plant protoplast (Planta (2008) 227, (1187-1197) DOI: 10.1007/s00425-008-0689- 1)

Upon publication of the above-mentioned paper, we regretfully became aware that Professor Hamako Sasamoto, who is listed as one of the coauthors of this work, was not aVorded the required opportunity to know about this manuscript, or to comment about its content. This omission constitutes unauthorized and inappropriate use of Professor Sasamoto’s name and is a clear violation of Planta’s express instruction to corresponding authors that “Submission of a manuscript implies that its publication has been approved by all coauthors.”