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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 23, 281-282 (2002) EDITORIAL - CRYOPRESERVATION AND GLOBAL WARMING! Hugh W. Pritchard, Royal Botanic Gardens Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN, UK
CryoLetters 23, 283-290 (2002) CRYOPRESERVATION OF Quercus suber AND Quercus ilex EMBRYONIC AXES: IN VITRO CULTURE, DESICCATION AND COOLING FACTORS M. Elena González-Benito*, Roberto-Moreno Prieto, Esther Herradón and Carmen Martín Departamento de Biología Vegetal, Escuela Universitaria de Ingeniería Técnica Agrícola, Universidad Politécnica de Madrid, Ciudad Universitaria, 28040 Madrid, Spain. email: gonzalez@agricolas.upm.es Abstract This study examines different factors included in the cryopreservation protocols for Quercus ilex and Q. suber embryonic axes. In vitro incubation temperature played an important role in the appropriate development of Q. ilex axes, as 15ºC was superior to 25ºC. Q. suber axes proved to be more sensitive to desiccation and cooling. Poor survival (35%) was observed when axes were included into cryovials and then in liquid nitrogen, and none when immersed in sub-cooled liquid nitrogen (-210ºC). Q. ilex axes showed poorly organised development in vitro (c. 50% of non-cooled axes showed shoot development). However, c. 80% survival was observed after cryopreservation (either in liquid nitrogen or sub-cooled liquid nitrogen at 0.34 g water / g dry weight), of which c. 15% showed shoot development. Keywords: desiccation, embryonic axes, liquid nitrogen, plantlet development, Quercus, germination temperature
CryoLetters 23, 291-298 (2002) A CRYOPRESERVATION PROTOCOL FOR EMBRYOS OF THE ENDANGERED SPECIES Zizania texana Christina Walters1*, Darren H. Touchell1, Paula Power2, James Wesley-Smith3 and Michael F. Antolin4 1USDA-ARS National Center for Genetic Resources, 1111 S. Mason Street, Fort Collins, Colorado, USA Abstract Seeds of the endangered species Zizania texana are recalcitrant, making it difficult to preserve the remaining genetic diversity of this species in genebanks. Excised embryos can be cryopreserved using solution-based cryoprotection protocols. Survival following cryoexposure increased from less than 5% to about 75% by preculturing embryos in high concentrations of sugars, bathing them in cryoprotectant solutions, and partially drying them to water contents of about 0.6 g H2O/g dry mass. Keywords: cryopreservation, desiccation tolerance, embryo, recalcitrant, vitrification, wildrice, Zizania
CryoLetters 23, 299-308 (2002) Cryopreservation of chayote (Sechium edule Jacq. SW.) zygotic embryos and shoot-tips from in vitro plantlets Ana Abdelnour-Esquivel1* and Florent Engelmann2, 3 1Centro de Investigación en Biotecnología, Instituto Tecnológico de Costa Rica (ITCR) (aabdelnour@itcr.ac.cr) Abstract This paper presents the development of cryopreservation protocols for zygotic embryos and apices of chayote (Sechium edule Jacq. Sw.), a tropical plant species with recalcitrant seeds. Zygotic embryos of two cultivars, Ccocro negro (CN) and Claudio (Cl) could withstand cryopreservation, with survival percentages of 10 and 30 %, after desiccation to 23 and 19 % moisture content (fresh weight basis), respectively. Apices sampled on in vitro plantlets of cultivars Cl, 13 and JM were successfully cryopreserved using a vitrification technique. Optimal conditions included the culture of mother-plants for 22 days on medium containing 0.3 M sucrose, culture of excised apices on the same medium for 1 day, loading of apices for 20 min with 2M glycerol + 0.4M glycerol, treatment with a series of diluted PVS2 solution (60 % PVS2 followed by 80 % PVS2 solution for 15 min (cultivar Cocoro Blanco [CB]) or 30 min (cultivars CN and Cl) at each concentration), rapid freezing and thawing, washing of shoot-tips with a 1.2 M sucrose solution, followed by recovery on media with progressively decreasing sucrose concentrations until the standard concentration of 0.1 M was reached. The highest survival percentages achieved ranged between 17 and 38 %, depending on the cultivar. Keywords: chayote; Sechium edule; cryopreservation; zygotic embryos; shoot tips; vitrification; desiccation.
CryoLetters 23, 309-316 (2002) Cryopreservation of Citrus aurantifolia seeds and embryonic axes using a desiccation protocol Eun Gi Cho1, 3*, Normah M. Noor2, Haeng Hoon Kim3, V. Ramanatha Rao1 and Florent Engelmann4, 5 1International Plant Genetic Resources Institute (IPGRI), Regional Office for Asia, Pacific and Oceania, P.O. Box 236, UPM Post Office, 43400 Serdang, Selangor Darul Ehsan, Malaysia. Abstract The desiccation and freezing tolerance of seeds, with and without testas, and embryonic axes of Citrus aurantifolia were investigated. Seeds were desiccated with silica gel, under the laminar air flow cabinet or by placing them on a laboratory bench. Whatever the desiccation method employed, survival before and after cryopreservation was higher for seeds without testas. When freezing intact seeds, the highest survival percentage (41.3 %) was achieved after desiccation to 7.3 % moisture content (fresh weight basis) on the laboratory bench. Survival of seeds cryopreserved without testas could reach up to 85 % after desiccation under the laminar air flow cabinet or on the laboratory bench, corresponding to moisture contents of 7.1 and 4.5 %, respectively. After desiccation with silica gel, survival reached a maximum of 60.0 %, for a seed moisture content of 3.3 %. Survival of control embryonic axes was high (80-100 %) whatever the sucrose concentration in the preculture medium and the duration of the desiccation period. After cryopreservation, no survival was noted with embryonic axes, which had not been precultured nor desiccated. Survival of non-desiccated embryonic axes after cryopreservation increased progressively in line with increasing sucrose concentrations in the preculture medium, from 7.5 % with 0.1 M sucrose to 77.5 % with 0.7 M sucrose. Survival of desiccated and cryopreserved embryos was always high, whatever the preculture treatment and desiccation period, ranging from 55.8 % to 92.5 %. Keywords: Citrus aurantifolia; seed; embryonic axis; desiccation; cryopreservation.
CryoLetters 23, 317-324 (2002) CRYOPRESERVATION OF Citrus madurensis Embryonic axes BY VITRIFICATION: importance of loading and treatment with vitrification solution Eun Gi Cho1, 3*, Y.L. Hor 2, Haeng Hoon Kim3 , V. Ramanatha Rao1 and Florent Engelmann4, 5 1International Plant Genetic Resources Institute (IPGRI), Regional Office for Asia, Pacific and Oceania, P.O. Box 236, UPM Post Office, 43400 Serdang, Selangor Darul Ehsan, Malaysia. Abstract This paper investigates the importance of loading and treatment with a vitrification solution on the survival of Citrus madurensis embryonic axes cryopreserved using a vitrification protocol. Among the seven different loading solutions tested, the solution containing 2 M glycerol + 0.4 M sucrose was the most efficient. Of the six vitrification solutions tested, the PVS2 vitrification solution, applied for 20 min at 25 °C or for 60 min at 0 °C, ensured the highest survival. A three-step vitrification protocol, involving the treatment of embryonic axes at 0 °C with half strength PVS2 solution for 20 min then with full strength PVS2 for an additional 40 min was more efficient than a two-step protocol that involved treatment of axes directly with full strength PVS2 solution for 60 min. After rapid immersion in liquid nitrogen, rapid rewarming, unloading in a 1.2 M sucrose solution for 20 min, culture on solid medium with 0.3 M sucrose for 1 day and growth recovery for 4 weeks on standard medium, survival of C. madurensis embryonic axes reached 85 % following the three-step process, compared with 70 % for the two-step process. Keywords: Citrus madurensis; embryonic axes; cryopreservation; preculture; loading; vitrification solution.
CryoLetters 23, 325-332 (2002) CRYOPRESERVATION OF Citrus madurensis EMBRYONIC AXES BY ENCAPSUlATION-DEHYDRATION Eun Gi Cho1, 3*, Y.L. Hor 2, Haeng Hoon Kim3 , V. Ramanatha Rao1 and Florent Engelmann4, 5 1International Plant Genetic Resources Institute (IPGRI), Regional Office for Asia, Pacific and Oceania, P.O. Box 236, UPM Post Office, 43400 Serdang, Selangor Darul Ehsan, Malaysia. Abstract In this paper, we demonstrate that C. madurensis embryonic axes can withstand cryopreservation using the encapsulation-dehydration technique. Up to 57.5 % survival was achieved using a standard encapsulation-dehydration protocol, which included pregrowth of encapsulated axes for 16 h in medium containing 0.8 M sucrose + 1 M glycerol, desiccation of beads to around 30 % moisture content (fresh weight basis) followed by rapid freezing. A slightly higher survival percentage (65 %) was obtained using a modified encapsulation-dehydration protocol, which included pretreatment of axes with 2 M glycerol + 0.6 M sucrose for 1 h, concomitantly with their encapsulation in 3 % calcium alginate beads, followed by desiccation of the beads to around 30 % moisture content. Keywords: Citrus madurensis; embryonic axes; cryopreservation; encapsulation-dehydration; pretreatment.
CryoLetters 23, 333-344-308 (2002) Cryopreservation of human ovarian tissue by direct plunging into liquid nitrogen: negative effect of disaccharides in vitrification solution V. Isachenko*, E. Isachenko, G. Rahimi, A. Krivokharchenko1, JL Alabart2, and F. Nawroth Department of Obstetrics and Gynaecology, University of Cologne, Kerpener Str. 34, 50931 Cologne, Germany; Abstract Given that it has been possible to successfully cryopreserve human ovarian tissue by direct plunging into liquid nitrogen, this study was designed to establish the future direction to be taken in this line of research. Bovine oviductal epithelial fragments (as a tissue model) and large biopsy fragments (~2.0 mm3) of human ovarian tissue were used for cryopreservation. Two protocols were tested: with permeable cryoprotectants (dimethyl sulphoxide, propylene glycol, glycerol) + egg yolk + sucrose or trehalose + a synthetic blocker of ice nucleation, Supercool X-1000; and using only permeable cryoprotectants (glycerol and ethylene glycol) + egg yolk + Supercool X-1000. The cryopreserved tissue specimens were subsequently thawed and the cryoprotectants removed by dilution in graded sucrose solutions. Both the dynamic growth and hormonal activity of the ovarian tissue pieces, vitrified using only permeable cryoprotectants, were greater than after vitrification in a mixture of permeable cryoprotectants and sucrose. Unlike the case for other reproductive tissue (spermatozoa, oocytes, embryos), these findings suggest that the cryopreservation of ovarian tissue by direct plunging into liquid nitrogen must be achieved by vitrification using only permeable cryoprotectants and agents that prevention ice formation. Keywords: human ovarian tissue without follicles, vitrification, development, estradiol-17β, progesterone
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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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