For different concentrate solutions of several kinds of solute, the homogeneous nucleation temperature Th and the equilibrium melting point Tm were determined by using so-called emulsion method. The obtained Th and Tm for each solute dropped with concentration increasing, however, the relationship between both temperatures showed good linearity with different gradients depending on the kind of solute. That is, the relations could be expressed by an equation Th=a・Tm for each solute, of which the gradients a are considered to represent the degree of supercooling ability. The correlation between the a values for each solute and the chemical structure or hydrate characters was examined. As a result, the dynamic hydration number of solute was found to have a good correlation with the a value representing supercooling ability.

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We are cryopreserving and banking the human umbilical cord blood (UCB) for the clinical application for the hematopoietic stem cell transplantation. UCB is the alternative stem cell source instead of the bone marrow or peripheral blood progenitor cells for the treatment of hematologic malignancies, inherited metaboloc disorders, and congenital immunodeficiencies. We have already cryopreserved more than l,500units of UCB, and more than 38 recipients have already transplanted. We think cryopreservation of UCB is useful not only for the hematopoietic stem cell transplantation but also for the forth coming cell-mediated-immunotherapy using UCB.

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The molecular mobility of lyophilized formulations containing various polymer excipients was determined by solid state pulsed ^1H-NMR and high resolution ^<13>C-NMR, and discussed in relation to protein stability in the formulations. The critical mobility temperature, T_<mc> of these formulations, at which a Lorentzian relaxation process due to liquid-like polymer protons appeared, varied among the polymer excipients, and increased with decreasing water content and increasing polymer molecular weight. The correlation time, τc, of carbonyl carbon of bovine serum γ-globulin in formulations containing dextran decreased substantially at temperatures above T_<mc> in a similar way as the τc of dextran methin carbon. This suggests that the molecular mobility of protein is enhanced at temperatures above T_<mc> by the increased mobility of dextran molecules. Protein aggregation during the storage of these formulations increased substantially at temperatures above T_<mc>, indicating that storage stability of lyophilized protein formulations is closelv related to their molecular mobility.

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In the space station, many kinds of biological experiments will be performed. In order to support the experiments, it is important to have the knowledge of preservation conditions such as temperature for biological materials including microorganisms and animal cells. In this paper, we show results of our preservation tests of three Escherichia coli (E. coli) strains (H/r30R, HsSOR, NG30), of which irradiation sensitivities are different, and three animal cell lines (L5178Y, M10, C3H10T1/2). Three months preservation tests showed that -72℃ is good temperature because high survival fractions and low mutation frequencies were observed in the E. coli strains. X-ray irradiation (0 -75 Gy) at -72℃ did not affect but carbon ion beam affected survival fractions and mutation frequencies of the E. coli strains. The effects by carbon ion beam at -72℃ were much lesser than that at 4℃. For the animal cells, survival fractions, mutation frequencies and transformation efficiencies after preservation at -80℃ were similar to those in liquid nitrogen. L5178Y and M10 cells at -72℃ were more resistant to X-ray irradiation (0.5 Gy) than at room temperature. Taken together, -72℃〜-80℃ could be an ideal temperature for 3 months preservation of microorganisms and animal cells in the soace environments.

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This study has been conducted to predict heat transfer process and injury of cell during freezing of biological tissue. The physicochemical model has been developed, and the freezing of biological tissue was simulated in relating with the following micro-behavior; the partial freezing outside the cell, water permeation through cell membrane, ice formation inside cell at nucleation stage, and others relevant to the freezing injuries. By connecting the experimental and analytical method, viability of cell during freezing process was quantitatively discussed in conjunction with macro-heat transfer.

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The Human Genome Project is considered to have an enormous impact to the future study in biology as well as medicine. The researches are entering into the new phase of this project, the emphases of which are large-scale sequencing of the human genome, systemetic polymorphism analysis, and systematic gene expression analysis. Recent progresses of this project are reviewed in this article.

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Recent drastic advance in cryobiology/cryotechnology enables to enhance the commercial and research use of mammalian embryos. In this study, we conducted experiments to establish the efficient cryopreservation method for bovine oocytes and the embryos derived from in vitro fertilization. By using vitrification method, post-thaw survival rate achieved to 97% for IVF blastocysts and also high survival (72%)was obtained for oocytes. Moreover, hundreds of healthy calves have been delivered after transfer of the embryos cryopreserved at oocyte or blastocyst stages, respectively. These results demonstrate that the vitrification method in the present study can be a practical use of bovine oocytes and embryos.

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With increasing numbers of germplasms requiring conservation, the demands are on the development of long-term conservation of clonal materials. Cryopreservation is the only current method that could provide the ideal condition for base collection of vegetatively propagated plant germplasms. There are growing interests and needs for cryopreservation. In recent years, detailed conditions of cryogenic procedures such as vitrification, encapsulation-vitrification and encapsulation-dehydration were well investigated and successful protocols for wider range of plant species have been developed. Cryopreservation is recognized as a practical and efficient tool for long-term storage of vegetatively propagated not only for the cold-hardy and temperate but also for tropical plant germplasms.

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Model marine organisms have contributed to many fields of pure and applied marine sciences. Since diversity of marine organisms comes to a crisis in company with the development of an ocean late years, protection of marine organisms is a urgent subject. The present paper deals with a short review of the present status on pedigree-preservation of marine organism resources featuring marine plants.

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Live animals and plants are used as food for many types of commercially important aquatic organisms, and although research continues, inert feeds have not fully replaced live foods. In particular, microalgae are of great importance to the commercial culture of bivalves, crustaceans, zooplankton, and to a lesser degree, finfish. Primary producers such as algae form the base of the pyramid, and as such constitute the largest link in the food chain. Zooplankton, specifically rotifers, are indispensable in the intensive culture of marine larval finfish and additionally serve as food for a number of other taxa. Therefore, the establishment of simple and reliable long-term preservation of these microalgae and zooplankton is indispensable to make the efficient larval rearing methods of marine finfish and invertebrates. Cryopreservation is one of the ideal methods, however, it is not entirely accomplished. Therefore, batch style culture and semi-continuous culture have been popularly used in the preservation of food organisms. In this paper, I will introduce the practical preservation methods which have been adopted in many hatcheries in Japan.

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