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ABSTRACT ARCHIVE |
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CryoLetters is a bimonthly, international journal for low temperature science and technology |
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CryoLetters 26 (5), 277-278 (2005) EDITORIAL:
CryoLetters 26 (5), 279-288 (2005) THE INFLUENCE OF 1-10 kD FRACTION FROM BRAINS OF THE HIBERNATING GROUND SQUIRREL AND THE YAKUT HORSE ON PROLIFERATION AND PROTEIN SYNTHESIZING SYSTEM OF EHRLICH ASCITIC CARCINOMA CELLS A.K. Gulevsky*, V.I. Grischenko, O.S. Tereschenko and I.J. Shchenyavcky Institute for Problems of Cryobiology and Cryomedicine of the National Akademy of Sciences of Ukraine, 23 Pereyaslavskaya. Street, 61015 Kharkov-15, Ukraine. Abstract The experimental data presented in the work testify to the cytostatic activity of 1-10 kD polypeptide fractions from brains of the hibernating ground squirrel and the Yakut horse towards Ehrlich ascitic carcinoma (EAC) cells. The experiments on the investigation of the inhibiting influence of 1-10 kD fractions from tissues of the hibernating and cold-adapted animals on protein-synthesizing system of EAC cells allow us to conclude that the cytostatic effect of the fractions is effected at the genetic level in the tumor cells. Keywords: cold-adapted animals, polypeptide fractions, cytostatic activity.
CryoLetters 26 (5), 289-296 (2005) THERMAL ANALYSIS OF TERTIARY BUTYL ALCOHOL/SUCROSE/WATER TERNARY SYSTEM Jian-Guo Zuo, Tse-Chao Hua*, Bao-Lin Liu and Guo-Yan Zhou Institute of Cryomedicine and Food Freezing, Shanghai University of Science and Technology, No.516 Jun-Gong Road, Shanghai 200093, China. Abstract The purpose of this work is to investigate the freezing properties of tertiary butyl alcohol (TBA)/sucrose/water ternary system. Differential scanning calorimetry (DSC) is employed to determine the glass transition temperature of the maximally freeze-concentrated solution Tg’ and the crystallization (or devitrification) temperature Tr. DSC measurements show that the presence of sucrose hinders the crystallization of TBA during cooling. The residual TBA in the glassy state will cause a decrease in Tg’ and will crystallize during heating. An increase in the cooling rate causes a decrease in Tg’. For 10% TBA/10% sucrose/water ternary system, the critical heating rate is approximately 250ºC/min. Annealing treatment at temperatures below Tg’ causes the crystallization of TBA, which indicates that TBA molecules still have appreciable mobility even at temperatures below Tg’. When the ratio of TBA to sucrose is less than 0.2, TBA cannot crystallize during cooling. Keywords: freeze-drying, tertiary butyl alcohol (TBA), sucrose, glass transition, differential scanning calorimetry (DSC), annealing
CryoLetters 26 (5), 297-304 (2005) RUMINATIONS ON HEAT AND MASS TRANSFER IN FREEZE DRYING: A PERSONAL REFLECTION Terence Rowe Castro Urdiales, Balmaseda, Spain. Contact: PMatejt@nibsc.ac.uk Abstract Examples are given to clarify the difference between heat and temperature, the sequence involving the passage of heat to and within a sample undergoing freeze-drying at reduced pressure is scrutinised and the beneficial and counterproductive effects of “modifying the vacuum” are examined together with the mechanism involved. The commentator also glances at possibly undesirable contamination of the product and the system as well as questioning the various forms of measurement of vacuum and temperature and their significance in validation procedures. An assertion is made that if the process is correctly conducted. The sublimation phase will be a square law function of the product depth and not a linear one. A proposal is made that heat input should be based on a variable energy profile (with appropriate safeguards) rather than on the basis of shelf temperature.
CryoLetters 26 (5), 305-312 (2005) Effect of Cooling and Exposure to Ethylene Glycol on In Vitro Maturation and Embryo Development of Rhesus Oocytes Catherine A. VandeVoort 1, 2, * and S. P. Leibo 3, 4 1California Regional Primate Research Center; Abstract The meiotic spindle of metaphase II-stage oocytes is damaged when mature oocytes are cooled to temperatures close to 0°C, as occurs during cryopreservation by equilibrium cooling. Since a spindle has not yet formed within a germinal vesicle-stage oocyte, it has been suggested that immature oocytes may be more resistant than metaphase II oocytes to cryopreservation by equilibrium cooling. To test this proposition, we examined the effects on rhesus macaque oocytes of chilling and exposure to ethylene glycol (EG) on their maturation and embryo development. A total of 202 cumulusintact oocytes was collected from adult female rhesus monkeys that had been given follicle stimulating hormone for controlled ovarian hyperstimulation. Within two hours of their having been aspirated and prior to germinal vesicle breakdown, oocytes were either cooled to 0°C for 10 minutes or were exposed for 15 minutes at 35°C to 1.5 M EG to be tested as a possible cryoprotectant. After being exposed, oocytes were cultured in maturation medium, fertilized in vitro with rhesus spermatozoa, and cultured. The maturation rate and subsequent development into blastocysts of those oocytes that had been exposed to EG or cooled to 0°C did not differ significantly from untreated control oocytes. Additional germinal vesicle oocytes were exposed to 1.5 M EG at 35°C for 3 minutes and then supercooled to 7°C or frozen at 7°C or frozen at 0.5ºC to 35°C. Rates of maturation and embryo development of oocytes cooled to or frozen at 7ºC were significantly lower than rates for control oocytes; none of those frozen to 35ºC even underwent maturation. These results suggest that germinal vesiclestage oocytes may be less susceptible to injury resulting from chilling or exposure to ethylene glycol, but are still damaged by freezing. Keywords: Rhesus macaque, cryopreservation, oocytes, cooling, ethylene glycol.
CryoLetters 26 (5), 313-322 (2005) Plant regrowth from potato shoot tips Cryopreserved by a combined vitrification-droplet method A. Halmagyi*, C. Deliu and A. Coste Institute of Biological Research, 48 Republicii str. RO-400015, Cluj-Napoca, Romania. Abstract Shoot tips obtained from in vitro potato plants (three cultivars) were successfully cryopreserved by the combined vitrification-droplet method and subsequently regenerated shoots. The effect of apex size, sucrose concentration, preculture duration and cold hardening treatments on viability of cryopreserved shoot tips was studied. The excised shoot tips were incubated, precultured and dehydrated with concentrated PVS2 cryoprotective solution at room temperature, prior to a direct plunge in liquid nitrogen. After rapid rewarming in Murashige-Skoog (MS) liquid medium, shoot tips were plated on semisolid MS medium (3.5 g/l agar) supplemented with 0.4 mg l-1 gibberellic acid, 0.5 mg l-1 zeatin, 0.2 mg l-1 indole-3-acetic acid and 30 g l-1 sucrose for regrowth. Cryopreserved shoot tips resumed growth within 20 days and regenerated shoots within 30 days. The highest regrowth levels of apices after cryopreservation were 55% recovery for cv. Désirée, 51% for cv. Ostara and 46% for cv. Santé. Keywords: vitrification, shoot tips, axillary buds, preculture, dehydration.
CryoLetters 26 (5), 323-332 (2005) CRYOPRESERVATION OF APPLE USING NON-DESICCATED SECTIONS FROM WINTER-COLLECTED SCIONS Leigh E. Towill and Remi Bonnart USDA-ARS National Center for Genetic Resources Preservation, Fort Collins, CO 80521 Abstract Winter vegetative buds of Malus species are cryopreserved at USDA-ARS NCGRP to backup genetic resources maintained by field collections. The method uses desiccation of nodal sections prior to cooling but is time and labor intensive, and can damage materials if excessive. Here we tested cooling sections without prior desiccation to improve the efficiency of handling. Sections were slowly cooled to -30°C or -35°C and transferred to the vapor phase over liquid nitrogen (LNV). Viability was assessed using a sprouting test or grafting test. Some accessions showed higher viability when cooled at 5°C/day compared to 1°C/h and when transferred to LNV at -35°C compared to -30°C. Ten of 20 species had accessions that were successfully cryopreserved using a criterion of 50% or greater sprouting. Desiccation prior to cooling was not necessary for cryopreservation of winter-collected scions from these Malus species. Keywords: conservation, germplasm, Malus species, two-step cooling, grafting.
CryoLetters 26 (5), 333-340 (2005) ULTRASTRUCTURAL IMPLICATIONS OF PRETREATMENT FOR SUCCESSFUL CRYOPRESERVATION OF Oncidium PROTOCORM-LIKE BODY Nae-Hwey Miao, Yasuko Kaneko and Yasutake Sugawara Department of Regulation-Biology, Faculty of Science, Saitama University, Saitama, 338-8570, Japan Abstract By applying pre-treatment with high concentrations of sucrose and glycerol prior to desiccation and subsequent freezing in liquid nitrogen, successful cryopreservation with high recovery rate was achieved in Oncidium PLB(protocorm-like body). Cellular and subcellular changes after each step in various cryopreservation regimes were examined to elucidate the mechanism of the beneficial effect of the pretreatment which confers resistance to desiccation and freezing. Key words: Cryopreservation, Desiccation and freezing injury, Electron microscopic observation, Oncidium hamana “elfin”, Protocorm-like body (PLB). |
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For Abstracts published from meetings, such as SLTB meetings, go to the
relevant Volume Year of the journal (above). For Full text Free Access Content (from 2000 onwards) go to CryoLetters at Ingenta and look for the blue symbol. |
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