降低黄芩再生苗玻璃化率及其生根的研究

为了降低黄芩组培苗的玻璃化率并提高其生根率,本研究以黄芩无菌苗茎段诱导的不定芽为实验材料,分别研究了6-苄基嘌呤(6-BA)、蔗糖、琼脂及多效唑(PP333)等组培条件对黄芩不定芽玻璃化的影响以及吲哚丁酸(IBA)对再生苗生根的影响。研究结果表明:低浓度的6-BA有利于降低不定芽的玻璃化率,当培养基中添加0.2 mg·L~(-1)6-BA时,不定芽的玻璃化率最低且增殖系数比对照增加1倍。随着培养基中蔗糖浓度的升高,不定芽的玻璃化率显著降低,其增殖系数也有所降低。培养基中蔗糖浓度为25 g·L~(-1)时,黄芩不定芽长势最好且玻璃化率为零,增殖系数也最高。培养基中添加7.5 g·L~(-1)的琼脂,不定芽的玻璃化率较低,增殖系数也较高。培养基中添加多效唑(PP333)有利于缓解黄芩再生不定芽玻璃化状态,随着PP333的浓度增加,玻璃化率也逐渐降低。0.2 mg·L~(-1)PP333对黄芩不定芽的壮苗起到了很好的作用,再生苗明显变得粗壮。0.1 mg·L~(-1)的IBA最有利于黄芩再生苗的生根,生根率为100%,平均生根数为7,移栽成活率达95%以上。     

酸枣叶片不定梢形成及玻璃化的影响因素

以酸枣无菌苗叶片为外植体,研究了培养条件对不定梢再生及不定梢玻璃化的影响.结果表明,叶片在加有细胞分裂素TDZ的诱导培养基(培养基Ⅰ)上连续培养,可诱导不定芽形成,但不能进一步发育成不定梢;而在诱导培养基Ⅰ上培养2周后转移到不加TDZ的培养基Ⅱ上,可获得不定芽伸长的不定梢.培养基Ⅱ的基本培养基组成影响不定芽(梢)的玻璃化症状:MS培养基产生玻璃化的不定芽(梢),而WPM培养基产生正常不定芽梢;光培养条件的变化对玻璃化症状的发生没有影响.不定芽(梢)玻璃化的发生可能与培养基中铵或硝酸铵的浓度有关,在不定芽伸长发育阶段,培养基中高浓度的铵导致了玻璃化苗的发生.     

甜瓜离体再生继代培养中玻璃化现象的研究

为提高甜瓜离体培养的再生率和转基因效率,以优质甜瓜品种‘伽师瓜’(‘卡拉库赛’)离体再生不定芽为外植体,通过连续多代继代培养,对引起玻璃化苗现象的几个主要因素进行了研究。结果表明,在甜瓜离体再生继代培养中,外植体继代次数是影响玻璃化发生的主要因素,同时培养基中的6-BA浓度偏高、琼脂浓度偏低以及蔗糖浓度偏低或偏高等可导致玻璃化苗的增加。培养基中较低的6-BA浓度(0~0.2 mg/L),琼脂浓度为6 g/L,蔗糖浓度为25 g/L以及添加活性炭等措施可有效地降低甜瓜玻璃化苗的发生。     

杂种甜椒的离体快速繁殖（简报）

甜椒F1子叶柄的不定芽诱导率比子叶尖的高;暗培养5d后转入光照下培养,促进不定芽的形成和缩短培养周期;6-BA5.0mg@L-1与IAA0.5mg@L-1组合的不定芽诱导率较高;培养基中添加水解酪蛋白和AgNO3后,不定芽诱导率降低;增殖培养基中添加15%椰汁明显改善试管苗的玻璃化和脱叶现象.     

不同因素对草莓玻璃化试管苗恢复的影响

旨在探索草莓玻璃化试管苗恢复措施。以‘丰香’草莓玻璃化试管苗为材料,采用正交设计的方法,在继代培养基中添加不同浓度组合的活性炭、聚乙烯醇和钙离子(氯化钙),研究不同组合对草莓玻璃化试管苗恢复的影响,同时比较恢复后的正常试管苗与原来的玻璃化苗及正常苗的生理生化指标。结果表明,正交设计的9种处理间草莓玻璃化苗的恢复率差异显著,恢复率最高的是处理9(1 g/L活性炭+2 g/L聚乙烯醇+166 mg/L钙离子),恢复率为89.07%,其次是处理4(0.5 g/L活性炭+166mg/L钙离子),81.05%、处理8(1 g/L活性炭+1 g/L聚乙烯醇),73.87%。方差分析表明,活性炭、聚乙烯醇、钙离子浓度对草莓玻璃化苗恢复的影响都极为显著,影响大小依次是钙离子>活性炭>聚乙烯醇。恢复苗的各项生理生化指标与玻璃化苗差异显著,与正常苗差异不显著。结合各处理对玻璃化苗的恢复率、生理生化指标及增殖系数,综合考虑认为使草莓玻璃化试管苗恢复的最佳处理为处理9。     

中国石竹离体快繁与试管苗玻璃化研究

研究了培养基组成成分对中国石竹品种Diana F1 White组培程序中种子萌发、诱芽增殖、试管苗玻璃化及生根等重要环节的影响。结果表明:(1)种子适宜的萌发培养基为1/2MS,在此培养基中种子萌发率为83.33%,播种后30d时无菌苗高度达6.99cm,叶片数达26.7。(2)在芽诱导阶段玻璃化苗发生率最高可达53.85%。将光照强度提高至2000lx后,采用培养基MS+6-BA3.0mg/L+NAA0.3mg/L+琼脂8.0g/L+蔗糖8.0g/L进行诱芽培养,玻璃化苗发生率降至3.33%,外植体出芽率达到90%,单个外植体出芽数达到7.2个。(3)适宜的生根培养基为1/2MS+1.0mg/LIBA+琼脂8g/L+蔗糖40g/L,培养30d时生根率为100%,平均根条数达到24.7条,平均根长度达到4.7cm。试管苗在消毒后的腐殖土中移栽,成活率达95%。该研究结果为DianaF1试管苗的快速繁殖提供科学依据。     

牡丹试管苗玻璃化的研究

以MS为基本培养基,研究品种、琼脂、6-BA、大量元素、蔗糖、光照等因素对牡丹试管苗玻璃化的影响。结果显示：不同品种的牡丹试管苗在组织培养的过程中,出现不同程度的玻璃化,增加培养基中琼脂浓度、降低细胞分裂素6-BA的浓度、降低大量元素的浓度和增加光照强度或采用自然光照均可以有效地降低试管苗玻璃化。     

江西铅山红芽芋胚性愈伤组织的玻璃化法超低温保存及植株再生

以江西铅山红芽芋胚性愈伤组织为材料,研究各种因素对其玻璃化法超低温保存的影响。结果表明:江西铅山红芽芋胚性愈伤组织玻璃化法超低温保存较佳的预培养条件为0.3mol·L-1蔗糖预培养3d,较佳的60%PVS2装载时间为20min,较佳的100%PVS2脱水条件为25℃脱水30min,较佳的化冻温度为40℃,较佳的洗涤液蔗糖浓度为1.2mol·L-1,较佳的冻后培养条件为暗培养7d再转到光周期中培养。红芽芋胚性愈伤组织包埋玻璃化超低温保存后的平均成活率约为70%。红芽芋胚性愈伤组织冻后再生苗没有发生形态学、生理学和细胞学的变异。     

几种因素对牙鲆胚胎玻璃化冷冻保存的影响

鱼类胚胎冷冻保存技术还远没有成熟, 为了寻找最佳的鱼类胚胎玻璃化冷冻保存条件, 我们以牙鲆(Paralichthys olivaceus) 胚胎为例, 研究了影响鱼类胚胎玻璃化冷冻保存的几个主要因子: 玻璃化液、麦管直径、胚胎阶段、平衡时间及平衡温度、洗脱浓度和洗脱时间。发现: (1) 含有多种抗冻剂的玻璃化液PMDD(2% PVP), 玻璃化稳定, 脱玻璃化率较低, 适宜进行玻璃化冷冻; (2) 尾芽期胚胎较其他时期耐受力强, 平衡40 min就足以使玻璃化液渗透完全, 时间延长, 成活率显著降低, 各个时期的胚胎对温度都比较敏感, 0°C与4°C下平衡的成活率显著高于15°C; (3) 洗脱浓度和洗脱时间对胚胎成活率影响不大; (4) 根据优化的条件, 对牙鲆两个时期的胚胎进行超低温冷冻保存实验, 共成活4次, 获得成活胚胎8粒, 其中7粒孵化出健康的鱼苗。本文为鱼类胚胎冷冻保存技术的建立提供基础资料, 并显示了牙鲆胚胎玻璃化冷冻保存是可行的。     

不同培养条件对薄荷试管苗玻璃化现象的影响

以江苏东台产薄荷(M entha haplocalyxB riq.)的茎尖为外植体,以MS为基本培养基,研究了培养基添加物和培养条件对薄荷试管苗玻璃化现象的影响。结果显示,导致薄荷玻璃化苗产生的主要因素是培养基中的6-BA、蔗糖和琼脂浓度以及培养温度和光照时间;当6-BA浓度为2 mg.L-1、蔗糖浓度为4%、琼脂浓度为0.70%、培养温度25℃、光照12 h.d-1(2 000 lx)时,薄荷试管苗的繁殖系数较高,玻璃化苗率较低。     

谷胱甘肽在小鼠卵母细胞玻璃化冷冻中的作用

目的：观察谷胱甘肽在小鼠玻璃化冷冻中的保护性作用。方法：通过卵母细胞是否玻璃化冷冻及是否添加GSH处理,将小鼠卵母细胞分为4组。检测卵母细胞内GSH浓度、ROS水平,以及通过彗星实验量化OTM值检测DNA碎片的生成。结果：在对照组、冷冻组、GSH处理组和GSH处理冷冻组细胞内GSH浓度分别为8．95±1．26、4．36±0．96、9．27±1．05和8．18±0．89;ROS水平分别为47．5±4．23、64．2±5．69、44．5±3．25and49．9±7．62。通过GSH处理,玻璃化冷冻卵母细胞出现彗尾百分比显著低于未处理组,差异具有统计学意义;通过GSH处理,玻璃化冷冻卵母细胞OTM值低于未处理组,差异无统计学意义。结论：玻璃化冷冻使小鼠卵母细胞产生一定的氧化应激损伤,表现为细胞内GSH浓度下降,ROS水平上升,DNA碎片增加,GSH处理可以在一定程度上改善。     

Optimization of triacetate cellulose hollow fiber vitrification (HFV) method for cryopreservation of in vitro matured bovine oocytes

The aim of the current work was to evaluate applicability of triacetate cellulose hollow fiber vitrification (HFV) method for cryopreservation of groups of in vitro matured bovine oocytes (12–17 oocytes per device). We also attempted to optimize HFV protocol by altering concentration of non-permeating cryoprotectant (sucrose) in vitrification solution and concentration of extracellular Ca²⁺ by using a calcium-free base medium for preparation of vitrification/rewarming solutions with ethylene glycol (EG) as a single permeating cryoprotectant. Neither of modifications of HFV protocol significantly affected survival or fertilization rates of the vitrified bovine oocytes. Embryo development rates in the vitrification groups were lower than those in the control (31.2% of blastocysts at Day 8 post IVF). Use of vitrification/rewarming solutions with lower Ca²⁺ concentration and EG did not significantly improve embryo development rates. An increase of sucrose concentration in vitrification solution from 0.5 to 1.0 M significantly improved blastocyst yield on Day 8 post IVF (21.1–23.4% vs 3.1–3.5%; p < 0.05). Obtained results indicated that sufficient dehydration of the oocytes and/or the solution surrounding them in hollow fiber before immersion into liquid nitrogen is an important factor for successful vitrification. Use of HFV method allowed simplification and standardization of vitrification/rewarming procedures. Triacetate cellulose hollow fibers can be used successfully for cryopeservation of groups of in vitro matured bovine oocytes.     

Sugars exert a major influence on the vitrification properties of ethylene glycol-based solutions and have low toxicity to embryos and oocytes

A systematic approach was taken to assess the vitrification properties of ethylene glycol-based solutions supplemented with carbohydrates. Solutions were prepared by weight (gravimetrically) using ethylene glycol as the cryoprotectant, 0.9% NaCl in water, and six different sugars: d-glucose, d(-)-fructose, d-sorbitol, sucrose, d(+)-trehalose, and raffinose. Sugars were added on a molal basis (0. 1, 0.5, and 1 m). Characteristics of the solutions were measured during warming by differential scanning calorimetry using a cooling rate of 100 degrees C/min and a warming rate of 10 degrees C/min. In the absence of carbohydrates a 59 wt% EG-saline solution formed a stable glass. When EG was replaced by an equimolal concentration of glucose, fructose, or sorbitol (monosaccharides) at 0.1, 0.5, or 1.0 m there was no change in the total solute concentration at which vitrification occurred, but the glass transition (Tg) occurred at a higher temperature than in EG-saline alone. When EG was replaced by an equimolal concentration of sucrose or trehalose (disaccharides) both the Tg and the lowest total solute concentration required for vitrification became progressively higher as the molecular weight, or the ratio of sugar to EG in the solutions, increased. At the highest tested disaccharide concentration (1 m) vitrification was achieved at a total solute concentration of 65 wt% (sucrose) and 67 wt% (trehalose). The polysaccharide raffinose significantly modified the vitrification properties of ethylene glycol solutions. When 0.5 or 0.1 m raffinose replaced EG on an equimolal basis the glass transition point was raised more than with either the monosaccharides or the disaccharides. Raffinose allowed vitrification at a total solute concentration of 67 wt% (0.5 m) and 63 wt% (0.1 m). The maturation of immature mouse oocytes, and the development of embryos in media containing 5-7 mM of any sugar was comparable to controls, indicating that they are not toxic. Exposure of freshly collected GV or MII oocytes to sugar concentrations between 0.5 and 1.0 M, for up to 10 min had no significant effect on the proportion which subsequently formed two cells. We conclude that added sugars do contribute to a solutions overall vitrification properties, and their properties should be taken into consideration when vitrification solutions are being designed or modified.     

Changes of soluble sugars and ATP content during DMSO droplet freezing and PVS3 droplet vitrification of potato shoot tips

The potato's great genetic diversity needs to be maintained for future agricultural applications and can be preserved at ultra-low temperatures. To decipher detailed physiological processes, the aim of the study was to analyze the regrowth in 28 gene bank accessions and to reveal metabolite changes in a subset of four accessions that showed pronounced differences after shoot tip cryopreservation using DMSO droplet freezing and PVS3 droplet vitrification. Regrowth varied in all 28 genotypes ranging from 5% (‘Kagiri’) to 100% (‘Karakter’) and was higher after PVS3 droplet vitrification (71 ± 19%) than after cryopreservation using DMSO (54 ± 17%). Sucrose, glucose, and fructose were analyzed and showed significant increases after pre-culture in combination with PVS3 or DMSO and liquid nitrogen treatment and were reduced during regeneration. In contrast, adenosine triphosphate (ATP) reached its minimum concentration after cryoprotection and liquid nitrogen treatment and recovered most quickly after PVS3 droplet vitrification. A shortening of the explant pre-culture period reduced dramatically the regrowth after PVS3 vitrification. However, correlations between the shoot tip regrowth and sugar concentration were absent and significant at a low extent with ATP (r = 0.4, P < 0.01). Interestingly, several sub-cultivations of the donor plants from the previous stock affected negatively the regrowth. In conclusion, the cryopreservation protocol, genotypes, pre-culture period and number of sub-cultures affect the regrowth ability of explants, which was best estimated by the ATP concentration after low-temperature treatment. Due to the superior performance of PVS3, the routine potato cryopreservation at the Gatersleben gene bank was changed to PVS3 droplet vitrification.     

Development of a modified vitrification strategy suitable for subsequent scale-up for hepatocyte preservation

This work explores the design of a vitrification solution (VS) for scaled-up cryopreservation of hepatocytes, by adapting VS_basic (40% (v/v) ethylene glycol 0.6 M sucrose, i.e. 7.17 M ethylene glycol 0.6 M sucrose), previously proven effective in vitrifying bioengineered constructs and stem cells. The initial section of the scale-up study involved the selection of non-penetrating additives to supplement VS_basic and increase the solution’s total solute concentration. This involved a systematic approach with a step-by-step elimination of non-penetrating cryoprotectants, based on their effect on cells after long/short term exposures to high/low concentrations of the additives alone or in combinations, on the attachment ability of hepatocytes after exposure. At a second stage, hepatocyte suspension was vitrified and functions were assessed after continuous culture up to 5 days.Results indicated Ficoll as the least toxic additive. Within 60 min, the exposure of hepatocytes to a solution composed of 9% Ficoll + 0.6 M sucrose (10⁻³ M Ficoll + 0.6 M sucrose) sustained attachment efficiency of 95%, similar to control. Furthermore, this additive did not cause any detriment to the attachment of these cells when supplementing the base vitrification solution VS_basic. The addition of 9% Ficoll, raised the total solute concentration to 74.06% (w/v) with a negligible 10⁻³ M increase in molarity of the solution. This suggests main factor in inducing detriment to cells was the molar contribution of the additive.Vitrification protocol for scale-up condition sustained hepatocyte suspension attachment efficiency and albumin production. We conclude that although established approach will permit scaling-up of vitrification of hepatocyte suspension, vitrification of hepatocytes which are attached prior to vitrification is more effective by comparison.     

Factors affecting the survival of one- and two-cell rabbit embryos cryopreserved by vitrification

The effects of equilibration time, glycerol (GLY), and 1,2-propanediol (PROH) concentration, and of vitrification and sucrose solution on the viability of 1- and 2-cell rabbit embryos were investigated. After collection, the embryos were equilibrated for 5 or 10 minutes in phosphate buffered saline (PBS) containing 10% GLY-20% PROH and were exposed for 30 seconds at 4 degrees C or were exposed and vitrified in one of two vitrification solutions 35% GLY-35% PROH or 20% GLY-50% PROH. The in vitro survival rates of 1-cell embryos equilibrated for both 5 and 10 minutes were lower (34.0 and 48.0%, respectively) than those of 2-cell embryos (78.8 and 68.5%, respectively; P<0.01). No differences were noted in the viability of embryos exposed to the 2 vitrification solutions. Following vitrification in a mixture of 35% GLY-35% PROH, the survival rates of 1- and 2-cell embryos were 18.3 and 13.7% and 19.6 and 10.4% for 5 and 10 minutes of equilibration, respectively. The survival rates of 1- and 2-cell embryos vitrified in a solution of 20% GLY-50% PROH were 25.7 and 35.4% and 26.2 and 21.3% for 5 and 10 minutes of equilibration, respectively. The survival rates of 1-and 2-cell embryos stored in 1M sucrose solution were 63.8 and 84.0%, respectively. In conclusion, the viability of vitrified 1- and 2-cell rabbit embryos was reduced as a consequence of their equilibration before vitrification, the exposure to vitrification solution and the dilution in a sucrose solution rather than of the vitrification process itself.     

Immature bovine oocyte cryopreservation: comparison of different associations with ethylene glycol, glycerol and dimethylsulfoxide

Research on different cryoprotectants and their associations is important for successful vitrification, since greater cryoprotectant concentration of vitrification solution may be toxic to oocytes. The aim of the present research was to compare the efficiency of immature bovine oocyte vitrification in different associations of ethylene glycol (EG), glycerol and dimethylsulfoxide (Me(2)SO). In the first experiment, oocytes were exposed to the cryoprotectant for either 30 or 60s in final solutions of EG+DMSO1 (20% EG+20% Me(2)SO) or EG+DMSO2 (25% EG+25% Me(2)SO) or EG+GLY (25% EG+25% glycerol). In the second experiment, the oocytes were vitrified in open pulled straws (OPS) using 30s exposure of final solutions of EG+DMSO1 or EG+DMSO2 or EG+GLY. Maturation rates of 30s exposure groups were not different from the control, but 60s cryoprotectant exposure was toxic, decreasing maturation rates. The vitrification with EG+DMSO2 resulted in enhanced maturation rate (29.2%) as compared with EG+DMSO1 (11.7%) and EG+GLY (4.3%) treatments. These data demonstrate that concentration and type of cryoprotectant have important effects on the developmental competence of vitrified oocytes.     

Bovine oocyte vitrification: effect of ethylene glycol concentrations and meiotic stages

Success in oocyte cryopreservation is limited and several factors as cryoprotectant type or concentration and stage of oocyte meiotic maturation are involved. The aim of the present study was to evaluate the effect of maturation stage and ethylene glycol (EG) concentration on survival of bovine oocytes after vitrification. In experiment 1, kinetics of oocyte in vitro maturation (IVM) was evaluated. Germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I (MI), and metaphase II (MII) oocytes were found predominantly at 0, 0–10, 10–14, and 18–24 h of IVM, respectively. In experiment 2, in vitro embryo development after in vitro fertilization (IVF) of oocytes exposed to equilibrium (ES) and vitrification solution VS-1 (EG 30%), or VS-2 (EG 40%) at 0, 12 or 18 h of IVM was evaluated. Only blastocyst rate from oocytes vitrified in SV-2 after 18 h of IVM was different from control oocytes. Hatched blastocyst rates from oocytes vitrified in VS-1 after 12 and 18 h, and SV-2 after 18 h of IVM were different from unvitrified oocytes. In experiment 3, embryo development was examined after IVF of oocytes vitrified using VS-1 or VS-2 at 0, 12 or 18 h of IVM. Rates of blastocyst development after vitrification of oocytes in VS-1 at each time interval were similar. However, after vitrification in VS-2, blastocyst rates were less at 18 h than 0 h. Both cleavage rates and blastocyst rates were significantly less in all vitrification groups when compared to control group and only control oocytes hatched. In conclusion, both EG concentration and stage of meiotic maturation affect the developmental potential of oocytes after vitrification.     

Production of channel catfish with sperm cryopreserved by rapid non-equilibrium cooling

This report describes the feasibility of using vitrification for fish sperm. Vitrification can be used to preserve samples in the field and offers an alternative to conventional cryopreservation, although it has not been systematically studied for sperm of aquatic species. The overall goal of the project was to develop streamlined protocols that could be integrated into a standardized approach for vitrification of aquatic species germplasm. The objectives of the present study in channel catfish (Ictalurus punctatus) were to: (1) evaluate the acute toxicity of 5%, 10%, 20% and 30% methanol, N,N-dimethyl acetamide, dimethyl sulfoxide, 1,2-propanediol, and methyl glycol; (2) evaluate a range of devices commonly used for cryopreservation and vitrification of mammalian sperm; (3) compare vitrification with and without cryoprotectants; (4) evaluate the post-thaw membrane integrity of sperm vitrified in different cryoprotectant solutions, and (5) evaluate the ability of vitrified sperm to fertilize eggs. Cryoprotectant concentrations of higher than 20% were found to be toxic to sperm. Methanol and methyl glycol were the least toxic at a concentration of 20% with an exposure time of less than 5 min. We evaluated a method reported for human sperm, using small volumes in loops (15 μl) or cut standard straws (20 μl) with and without cryoprotectants plunged into liquid nitrogen. Cryoprotectant-free vitrification using loops did not yield fertilization (assessed by neurulation), and the fertilization rates observed in two trials using the cut standard straws were low (∼2%). In general, fertilization values for vitrification experiments were low and the use of low concentrations of cryoprotectants yielded lower fertilization (<10%) than the use of vitrification solutions containing high cryoprotectant concentrations (as high as 25%). The highest neurulation obtained was from a mixture of three cryoprotectants (20% methanol + 10% methyl glycol + 10% propanediol) with a single-step addition. This was reflected in the flow cytometry data from which the highest membrane integrity using loops was for 20% methanol + 10% methyl glycol + 10% propanediol (∼50%). We report the first successful sperm vitrification in fish and production of offspring from vitrified sperm in channel catfish. Although the fertilization values were low, at present this technique could nevertheless be used to reconstitute lines (especially in small aquarium fishes), but it would require improvement and scaling up before being useful as a production method for large-bodied fishes such as catfish.