 |
|||
|
ABSTRACT ARCHIVE |
|||
|
|||
|
|
 |
|
|
|
CryoLetters is a bimonthly, international journal for low temperature science and technology |
|
|
|
CryoLetters 32 (5), 367-376 (2011) cryopreservation of winter-Dormant apple buds: C. Vogiatzi1, B. W.W Grout1*, A.Wetten2 and B. T. Toldam-Andersen1 1Department of Agriculture and Ecology, University of Copenhagen, Højbakkegård Allé 13, DK-2630 Taastrup, Denmark Abstract The established protocol for the cryopreservation of winter-dormant Malus buds requires that stem explants, containing a single, dormant bud are desiccated at -4°C, for up to 14 days, to reduce their water content to 25-30% of fresh weight. Using three apple cultivars, with known differences in response to cryopreservation, the pattern of evaporative water loss has been characterised, including early freezing events in the bud and cortical tissues that allow further desiccation by water migration to extracellular ice. There were no significant differences between cultivars in this respect or in the proportions of tissue water lost during the desiccation process. Differential Scanning Calorimetry (to -90°C) of intact buds indicated that bud tissues of the cultivar with the poorest response to cryopreservation had the highest residual water content at the end of the desiccation process and froze at the highest temperature Keywords: Malus, cryopreservation, dormant bud, dehydration
CryoLetters 32 (5), 377-388 (2011) In vitro conservation of passiflora suberosa L.: SLOW growth and cryopreservation R.O. Garcia 1, 2, G. Pacheco1, M.G. Vianna1 and E. Mansur1* 1Instituto de Biologia Roberto Alcantara Gomes, Núcleo de Biotecnologia Vegetal, Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524 PHLC sala 505,
Maracanã, Rio de Janeiro 20550-013, Brazil. Abstract Passiflora suberosa is a tropical species used as an ornamental, in popular medicine and in improvement programs. The goal of this study was the development of in vitro conservation strategies for this species, including medium-term storage through slow growth, and long-term storage through cryopreservation using vitrification-based techniques. Plants were maintained under slow growth conditions on ½ MSM or ¼ MSM medium for 12 months without decrease in regrowth ability. The efficiency of vitrification and encapsulation-vitrification protocols was compared in order to determine the optimal conditions for successful cryopreservation. Several parameters were evaluated, including pregrowth on medium with high sucrose concentrations, type of vitrification solution (PVS2 and PVS3), exposure time to vitrification solutions, and recovery conditions. The highest recovery was obtained with the encapsulation-vitrification protocol after a pretreatment with 0.3 M sucrose and post-cryopreservation incubation in the dark for 30 days on MSM medium supplemented with 0.44 μM BA. Keywords: passion fruit, medium-term conservation, long-term conservation, vitrification, encapsulation-vitrification.
CryoLetters 32 (5), 389-401 (2011) rgds-fuctionalized alginates improve the survival rate of encapsulated embryonic stem cells during cryopreservation S Sambu, X Xu, HA Schiffter, ZF Cui and H Ye* Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, OX3 7DQTel: +44 1865 617689, Fax: +44 01865 617701 Abstract Cryopreservation of stem cells, especially embryonic stem cells, is problematic because of low post-thaw cell survival rates and spontaneous differentiation following recovery. In this investigation, mouse embryonic stem cells (mESCs) were encapsulated in arginine-glycine-aspartic acid-serine (RGDS)-coupled calcium alginates (1.2 wt%), allowed to attach to the substratum and then cryopreserved in 10% vol. dimethyl sulfoxide (DMSO) solution at a slow cooling rate of 1˚C/min. RGDS coupling to alginate was confirmed by Transmission Fourier Transform Infra-Red spectroscopy (T-FTIR) and quantified by using ninhydrin-Ultraviolet/Visible light (ninhydrin-UV/VIS) assay. Flow cytometry data showed that mESCs cryopreserved in RGDS-alginate beads had a higher expression of stem cell markers compared with cells cryopreserved in suspension or cells cryopreserved in unmodified alginates. Cell viability after thawing was assessed using trypan blue exclusion assay and monitored using Alamar blue assay for 6 hours. It was shown that post-thaw cell survival rate was significantly higher for cells encapsulated in RGDS-modified alginate (93±2%, mean and standard error) than those in suspension (52±2%) or in unmodified alginates (62±3%). These results showed that cells encapsulated and attached to a substratum have better survival rate and stem cell marker expression 24 hours after cryopreservation than those in suspension. Encapsulation in RGDS-alginate was optimized for peptide concentration, cryoprotective agent loading time and cooling rate. The best result was obtained when using 12.5 mg peptide /g alginate, 30 minutes loading time and 1C/min cooling rate. Keywords: RGDS, cryopreservation, alginate, mESCs, encapsulation
CryoLetters 32 (5), 402-409 (2011) CRYOPRESERVATION OF ADULT BOVINE TESTICULAR TISSUE FOR SPERMATOGONIA ENRICHMENT Jianying Wu2, 1, Tiejun Hu3, Bin Guo1, Zhanpeng Yue1, Zhengtao Yang1, and Xueming Zhang1* 1Jilin Province Key Laboratory of Animal Embryo Engineering, and the Center for Animal Embryo Engineering of Jilin Province, College of Animal Sciences and Veterinary Medicine,
Jilin University, 5333 Xi’an Road, Changchun 130062, Jilin Province, China. ABSTRACT To develop a procedure for cryopreservation of adult bovine testis tissue, the effects of dimethyl sulphoxide (DMSO), propylene glycol (PG), ethylene glycol (EG), and their concentrations (v/v), as well as different thawing temperatures, on the cell viability of bovine testis tissue after freezing/thawing were examined. The highest testicular cell viabilities came from the media containing DMSO (85.3 ± 1.2%), PG (82 ± 1.0%) and EG (83.4 ± 1.0%) at 10% concentration respectively. Using 10% DMSO gave significantly higher spermatogonia percentage (61.1 ± 1.2%, P < 0.001) than processing with 10% PG (54.3 ± 0.6%) or 10% EG (55 ± 1.8%) after differential plating. Thawing in water bath of 37 or 97-100°C also provided significantly higher viabilities (85.1 ± 1.0, 85 ± 1.0%, P < 0.01, respectively) and spermatogonia percentages (56.6 ± 2.0, 56.6 ± 2.6%, P < 0.01, respectively) than that thawing at 4°C (23.4 ± 0.8% for total viability, 8.97 ± 1.0% for spermatogonia percentage). Collectively, 10% DMSO and thawing in 37-100°C water baths were appropriate for the cryopreservation of bovine testicular tissue and subsequent spermatogonia enrichment. Keywords: bovine; cellular viability; cryopresevation; cryoprotectant; testis tissue
CryoLetters 32 (5), 410-414 (2011) effects of cryoprotectant agents and equilibration methods on developmental Competence of porcine oocytes Masayasu Taniguchi, Rie Arikawa, Yukine Kaedei, Fuminori Tanihara, Zhao Namula, Vien Luu Viet, Yoko Sato, and Takeshige Otoi* Laboratory of Animal Reproduction, Department of Veterinary Medicine, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan. Abstract Chemical toxicity of cryoprotectants to in vitro developmental competence of porcine oocytes was examined. In vitro-matured oocytes were exposed to 40% ethylene glycol (EG), glycerol (GLY), or 1,2-propanediol (PD), fertilized with spermatozoa, and cultured for 8 d. Compared to treatment with other cryoprotectants, exposure to EG resulted in the development of significantly more blastocysts, but the rate was significantly lower than that of non-exposed control oocytes. In vitro-matured oocytes were also equilibrated in 40% EG by 3 multi-step methods, after which their developmental competence was evaluated. The rate of blastocyst development was higher in the 4-step method than in the 2- and 3-step methods of equilibrium. These results indicate that cryoprotectants and equilibration methods affect the developmental competence of porcine oocytes and that EG may be a superior cryoprotectant for vitrification of these cells. Keywords: Cryoprotectant, equilibration, porcine, oocyte, toxicity, vitrification
CryoLetters 32 (5), 415-424 (2011) MEDIATED TREHALOSE UN-LOADING FOR REDUCED ERYTHROCYTE OSMOTIC FRAGILITY AND PHOSPHATIDYLSERINE TRANSLOCATION Andrew L. Lynch1* and Nigel K.H. Slater1 1Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge, CB2 3RA, United Kingdom Abstract Recently, high concentrations of intracellular trehalose (>200mM) were employed to enhance the cryoprotection and desiccation protection of human erythrocytes. However, significant challenges must be overcome if this advancement is to be translated into clinical practice. It is here demonstrated that 247 ± 5 mM intracellular trehalose caused the lysis of 60 ± 2% of erythrocytes upon resuspension in PBS of physiological osmolality (300 mOsm) and caused surviving cells to swell up to 140 ± 2% of isotonic cell volume. Trehalose loaded cells also exhibited 24 ± 1% incidence of phosphatidylserine translocation upon resuspension in 300 mOsm PBS, likely due to loading induced cell swelling. Un-loading of trehalose from erythrocytes using the membrane-permeabilizing biopolymer PP-50 was investigated as a technique to mitigate these damaging effects. After erythrocyte un-loading from 247 ± 5 mM to 39 ± 2 mM intracellular trehalose, cell lysis at 300 mOsm PBS was reduced from 60 ± 2% to 17 ± 3%. Un-loading also reduced cellular incidence of PS translocation in resuspended cells from 24 ± 1% to 13 ± 1%. Keywords: erythrocyte, trehalose, biopolymer, phosphatidylserine, osmotic fragility
CryoLetters 32 (5), 425-435 (2011) effect of various freezing solutions on cryopreservation of mesenchymal stem cells from different animal species Yang Liu1,2,3, Xia Xu1,4, Xuehu Ma3, Jing Liu2 and Zhanfeng Cui1,* 1Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK. Abstract The objective of this study is to compare the effects of different well defined freezing solutions with a reduced concentration of dimethylsulfoxide (DMSO) combined with polyethylene glycol (PEG) and/or trehalose on cryopreservation of mesenchymal stem cells (MSCs) from mice, rats and calves. Post-thaw cell viability, proliferation capacity and differentiation potential of MSCs from different species were assessed after cryopreservation with the conventional slow freezing method. Although the post-thaw viabilities and metabolic activities varied among the different species, satisfactory results were obtained with 5% (v/v) DMSO, 2% (w/v) PEG, 3% (w/v) trehalose and 2% (w/v) bovine serum albumin (BSA) as the freezing solution. Our results showed that mouse MSCs were more robust to cryopreservation compared with rat and bovine MSCs. Keywords: cryopreservation, mesenchymal stem cells, well defined freezing solutions
CryoLetters 32 (5), 436-446 (2011) Cryoprotective effect of an insect antifreeze protein MpAFP698 and its mutants from the desert beetle Microdera punctipennis Min Jiang, Ji. Ma* and Liming Qiu Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, China Abstract An insect antifreeze protein, MpAFP698, from the desert beetle Microdera punctipennis, shares 77% similarity with TmTHP (YL-3) from Tenebrio molitor. The predicted tertiary structure for MpAFP698 was modeled as a regular -helix with TCT motifs arrayed to form the putative ice-binding surface. This model was validated via site-directed mutagenesis. The results suggest that the desert beetle in central Asia has evolved antifreeze proteins similar to those from North America continent. In an additional study, the recombinant MpAFP698 and its mutants were expressed in Escherichia coli strain BL21 (DE3). The thermal hysteresis activity of MpAFP698 was 1.73°C at 1.0 mg/ml. MpAFP698 was also tested by in vitro antifreeze activity assay to evaluate its cryoprotective effect at -20°C. MpAFP698 displays high cryoprotective effect on bacteria cells at freezing temperatures. Keywords: antifreeze protein, Microdera punctipennis, site-directed mutagenesis, thermal hysteresis |
|
|
|
|
|
|
|
|
|
|||||||||||||||||||||||
|
Abstracts |
|||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||
|
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. |
|||||||||||||||||||||||||||
