Biomedical subjects

Jun-ichi Edahiro

Publications and source records attributed to Jun-ichi Edahiro.

4 recordsLinked to original sources

PubMed2006

Manipulation of living cells by using PC-controlled micro-pattern projection system.

In order to meet the diversifying demand for the cell manipulation in the rapid progress of cell engineering, we developed a novel technique to capture the living cells on a culture substrate by irradiating light in a multiple manner. In clear contrast to the conventional cell patterning using the previously patterned substrate, the cell-retaining area can be defined even after cell seeding, and the captured cells can continue to grow freely beyond the defined area afterwards. After the light irradiation in arbitrary micropattern by using a newly developed apparatus and the process to remove non-captured cells including EDTA treatment, the highly contrasted cell patterns were formed with the precision of single cell size. Moreover, it was determined that the cell capturing arose just after light irradiation and diminished gradually in a time scale of 10h. It was confirmed that the cells maintained their viability well after the manipulation process including photo-induced cell capturing.

Animals↗

PubMed2006

Photoresponse of an aqueous two-phase system composed of photochromic dextran.

A novel aqueous two-phase system, which exhibits a reversible photoinduced phase separation, has been developed with photochromic dextran synthesized by substituting 0.3 mol % of the hydroxyl groups with the photochromic chromophore, 6-nitrospiropyran (NSp). For an aqueous solution containing this photochromic dextran and poly(ethylene glycol), it was observed that the solution, which had been uniform in the dark, quickly separated into two phases through blue light irradiation within 1 min and returned to the former uniform state spontaneously after heating at 50 degrees C for 1 h. Photoisomerization of NSp was confirmed to shift the phase separation temperature of this aqueous two-phase system by up to 30 degrees C.

Benzopyrans↗

PubMed2006

Phenylpropanoid metabolite supports cell aggregate formation in strawberry cell suspension culture.

Plant cells in suspension culture tend to aggregate and form large clumps. In suspension culture, large cell aggregates are frequently subjected to hydrodynamic shear stress; however, a certain degree of cell aggregation is often required for cell growth and metabolite production. Thus, controlling cell-aggregate size is desired to establish high productivity of useful products using plant cell suspension culture. In this study, we focused on the relationship between cell-aggregate formation and secondary metabolism. We found that anthocyanin concentration showed a good correlation with cell-aggregate size in the cultured strawberry cell line FAR (Fragaria ananassa R), which produces anthocyanin and other phenylpropanoid metabolites constitutively without illumination. This result suggests that there is a relationship between cell-aggregate formation and the accumulation of phenylpropanoid metabolites. To investigate the direct effect of phenylpropanoid metabolism on cell-aggregate formation, the time course of cell-aggregate size was monitored when phenylpropanoid metabolism was suppressed by a metabolic inhibitor, L-alpha-aminooxy-beta-phenylpropionic acid (AOPP), a specific inhibitor of phenylalanine ammonia lyase which is the starting and key enzyme of the phenylpropanoid pathway. In the absence of AOPP, the average diameter of cell aggregates increased on day 8 of culture. This increase in cell-aggregate size was completely suppressed by the addition of 0.1 mM AOPP, without any reduction in cell growth rate or soluble protein content. These results indicate that cell-aggregate formation is directly supported by a secondary metabolite produced from the phenylpropanoid pathway, suggesting that cell-aggregate size can be controlled by AOPP without inhibition of primary metabolism.

Anthocyanins↗

PubMed2005

Separation of cultured strawberry cells producing anthocyanins in aqueous two-phase system.

A rapid and simple selection method of high-yield cells has been desired to establish highly productive cell lines for useful secondary metabolites. For this purpose, a new attempt was made to partition cultured plant cells in a poly(ethylene glycol)-dextran aqueous two-phase system (ATPS). The applicability of the ATPS in partitioning cultured strawberry cells (designated FAW) was investigated. The result of single-step partitioning in the ATPS supplemented with 0.4 mmol/kg lithium sulfate showed that FAW cells cultivated for 7 d under light-irradiation were separated into two cell populations with significantly different anthocyanin content. Additionally, the analysis technique of microscopic cell images showed that cells accumulating a high level of anthocyanin were partitioned completely into the bottom phase in a partitioning experiment of FAW cells cultivated for 10 d under light-irradiation in the ATPS supplemented with 1.8 mmol/kg potassium phosphate buffer. These results indicated that cell partitioning in ATPS increased the intracellular anthocyanin content and that the cultured strawberry cell population was heterogeneous in terms of cell surface properties. This is the first report of partitioning based on the heterogeneity of the cell surface properties correlated with the intracellular secondary metabolism in cultured plant cells. Our results also suggested that the ATPS was appropriate as a large-scale method for selecting useful cell lines among the cultured plant cells.

Anthocyanins↗