Carbonate apatite versus ß-tricalcium phosphate for rat vertical bone augmentation: A comparison of bioresorbable bone substitutes using polytetrafluoroethylene tubes.

This study radiologically and histologically compared two bioresorbable bone substitutes with different compositions carbonate apatite (Cytrans® Granules; CGs) and ß-tricalcium phosphate (ß-TCP) for vertical bone augmentation on a rat skull using a polytetrafluoroethylene (PTFE) tubes. This PTFE tube was placed at the center of the skull, fixed with Super Bond, and augmented with CGs or ß-TCP granules. Specimens with surrounding tissue were harvested at 4, 8, and 12 weeks postoperatively, and radiological and histological evaluations were performed. The bone volume to total volume ratio (BV/TV) of the ß-TCP-implanted group was markedly higher than that of the CG-implanted group at 4 and 12 weeks postoperatively. Compared to CGs, ß-TCP exhibited the ability to form blood vessels into the graft material for a short period after transplantation, as well as an elevated production of collagen into ß-TCP granules during the bone formation process.

Filter paper degrading ability of a Trichoderma strain with multinucleate conidia.

The multinucleate conidia were produced from the green mature conidia of Trichoderma reesei Rut C-30 strain by colchicine treatment. The strain with higher Filter paper degrading ability was selected among those conidia using a double layer selection medium. The selected strain, JS-2 was able to collapse the filter paper within 15 min but the original strain took 25 min to collapse it completely. Moreover, the amount of reducing sugar in the L-type glass tube of the strain, JS-2 was greater than that of the original strain. The Avicel, CMC-Na, and Salicin hydrolyzing activity of the strain, JS-2, increased 2.1 times, 1.2 times, and 3.6 times higher than that of the original strain.

Polykaryon formation using a swollen conidium of Trichoderma reesei.

The cellulolytic fungus, Trichoderma has oval and mononucleate conidia. When these conidia are incubated in a liquid medium, they begin to swell and their shape becomes spherical followed by an increase in inner space. In such swollen conidia, it is possible to produce a larger autopolyploid nucleus using a mitotic arrester compared with the case of the original conidia. In this study, polykaryon formation was attempted using these swollen conidia. Dried mature green conidia of Trichoderma reesei QM6a (IFO 31326) were incubated in Mandel's medium in order to swell. The swollen conidia were treated with a mitotic arrester, colchicine, for autopolyploidization. After autopolyploidization, polykaryon formation was carried out using the swollen conidia. After the treatment, multiple smaller nuclei whose diameter was almost the same as that of the original strain were generated from an autopolyploid nucleus in a swollen conidium. A cellulase hyperproducer without decrease in growth rate could be selected using such swollen conidia.

Active nuclear shuffling system using a swollen conidium of Trichoderma reesei.

Cellulase hyperproducers of Trichoderma reesei can be constructed using autopolyploidization and haploidization techniques. To increase the efficiency of this method, the active nuclear shuffling system in a swollen conidium was effective. A dried mature green conidium of a model strain, T. reesei QM6a (IFO 31326), was swollen to make room for a larger autopolyploid nucleus. After colchicine treatment, a larger autopolyploid nucleus was produced in such a swollen conidium. Benomyl treatment of swollen conidia generated multiple smaller nuclei from one larger autopolyploid nucleus. Those smaller nuclei were transported through conidia to mycelia after germination. This system could contribute to increasing the efficiency of genetic shuffling.

Transgenic expression of FGF8 and FGF10 induces transdifferentiation of pancreatic islet cells into hepatocytes and exocrine cells.

FGF signaling is essential for normal development of pancreatic islets. To examine the effects of overexpressed FGF8 and FGF10 on pancreatic development, we generated FGF8- and FGF10-transgenic mice (Tg mice) under the control of the glucagon promoter. In FGF8-Tg mice, hepatocyte-like cells were observed in the periphery of pancreatic islets, but areas of alpha and beta cells did not decrease, whereas in FGF10-Tg mice, pancreatic ductal and acinar cells were found in islets, concomitantly with disturbed beta-cell differentiation. These results suggest that FGF8 and FGF10 play important roles in development of hepatocytes and exocrine cells, respectively, and explain the absence of FGF8 expression in normal islets and pancreatic hypoplasia in FGF10-deficient mice.