牛活体采卵体外受精不分裂MⅡ期卵母细胞的研究

牛活体采卵体外成熟后,常规进行体外受精,平均卵裂率为73.1%。在卵裂率稳定的前提下,随机挑选96枚没有卵裂的MⅡ期卵母细胞进行Hoechst33342染色分析,以期找出卵子没有分裂的原因,为进一步提高卵裂率提供科学资料。结果发现精子没有进入卵母细胞的占59.4%,精子进入卵母细胞但雌雄原核未融合的占19.8%,多精受精引起发育阻滞的占13.5%。结果表明,在保证卵母细胞成熟的前提下,引起牛体外受精失败的主要原因是精子没有进入卵母细胞。     

LPS致肝细胞损伤模型的建立研究

[目的]探索LPS体外致人ChangLiver细胞损伤模型的建立方法和意义。[方法]分别用20．40、60、80、1130μg／ml浓度的LPS作用ChangLiVer细胞24h,采用MTF法检测LPS对ChangLivet细胞存活率的影响,分别测定ChangLiver细胞上清中谷草转氨酶（AST）、谷丙转氨酶（ALT）、碱性磷酸酶（ALP）、γ-谷氨酰转肽酶（γ-GT）、乳酸脱氢酶（IJDH）的活性,并通过Hoechst33258荧光染色观察用药24h后ChangLiver细胞形态的变化。[结果]80和100u晷／ml浓度的LPS作用后ChangLiver细胞存活率显著性降低,胞外AST、ALT、ALP、γ-GT、LDH酶活性升高,细胞数目减少,细胞形态发生改变,呈现细胞核固缩等细胞凋亡现象。（结论l用80μg/ml的LPS与ChangLiver细胞共培养24h,可以建立理想的体外肝细胞损伤模型。     

牛去核卵母细胞能够被孤雌激活并发育到桑椹胚

为了探讨实验牛去核卵母细胞能否被激活,及其激活后的发育能力,本研究利用化学激活法对牛去核卵母细胞进行孤雌激活,然后在体外颗粒细胞饲养层上进行培养,同时在不同的时间采用免疫荧光技术对α-微管蛋白(α-tubulin)进行染色,以观察去核卵母细胞与正常卵母细胞中微管分布动态变化的差别.结果表明去核卵母细胞经激活后在体外培养能够发育到桑椹胚,去核卵母细胞内α-tubulin的分布在分裂初期没有分区现象,对照组未去核卵母细胞内的α-tubulin抗体出现了分区现象.     

绿色荧光蛋白在鸡胚成纤维细胞中的表达

应用阳离子脂质体介导法,将含绿色荧光蛋白(GFP)基因的质粒pEGFP-C1转染到培养至第二代的鸡胚成纤维细胞(CEF)中,同时使用活体DNA染料Hoechst3334(2H342)对CEF细胞核荧光染色,通过荧光倒置显微镜和RT-PCR方法检测GFP的表达产物。在荧光倒置显微镜下可见CEF的胞质和核均呈现绿色荧光,且细胞核的绿色荧光强度强于细胞质,在H342作用下,细胞核呈现蓝色荧光;转染细胞中转录产物经RT-PCR扩增后,在凝胶上可见与GFP基因片段分子量大小一致的条带。可见,GFP基因可以被转染至CEF中,并在CEF中表达。     

家猪染色体的Q—分带研究

本文采用QFH显带法,对杜洛克、巴克夏和关中黑猪的Q-分带带型作了较为详细的研究。结果表明,不经BUdR预处理而直接用Hoechst 33258进行分,猪的每一条染色体均能显示出重现性良好的特征性荧光带——QFH带;QFH带与QFQ带带型基本一致,且以QFH带纹较精细。同时,就QFH带对着丝粒异染色质的鉴定作了初步探讨。     

用荧光染料（Hoechst 33342）和激光处理精子对牛卵母细胞体外受精的影响

用流动细胞计数法分离牛的Ｘ，Ｙ精子，需要对精子进行活体荧光染色及激光照射处理。本研究进行２个实验，以探索荧光染料（Ｈｏｅｃｈｓｔ３３３４２）和激光对牛精子以及牛卵母细胞的体外受精和胚胎的体外培养的影响。实验１包括４个精子处理组：（１）０处理组（对照组）；（２）染色组，用９ｍｇ／Ｌ的Ｈｏｅｃｈｓｔ３３３４２对精子进行染色；（３）激光照射组，用强度为１５０ｍＷ的激光对精子进行照射；（４）染色及激光照射组，综合（２）和（３）的处理。实验２用不同浓度的Ｈｏｅｃｈｓｔ３３３４２处理精子，以研究染料浓度与体外受精效果的关系。实验结果表明，Ｈｏｅｃｈｓｔ３３３４２作用于精子之后，能显著降低牛卵母细胞体外受精后的分裂率、囊胚率、一级囊胚率、囊胚孵化率及胚胎发育速度，而且降低的幅度随着染料浓度的升高而增加（卵裂率除外）。精子经激光照射后对体外受精的效果没有显著影响。     

HMC毒素诱导玉米同核C、N细胞质细胞凋亡的荧光显微观察

[目的]研究玉米小斑病菌C小种毒素(HMC-toxin)诱导同核异质体玉米的离体根冠细胞发生凋亡的差异性及凋亡规律.[方法]采用吖啶橙(AO)与溴化乙啶(EB)荧光复染以及Hoechst 33258荧光染色的方法检测.[结果]HMC毒素诱导根冠细胞发生凋亡,出现凋亡小体与染色体边集形态特征.在3种毒素浓度、3种处理时间下,Mo17-C的根冠细胞死亡率均高于Mo17-N.采用AO与EB复染方法,在150μg·mL<'-1>HMC毒素处理7 h时,M017-C细胞凋亡率达最高值,为68.7%,而Mo17-N仅为29%;经Hoechst 33258染色后,在150μg.mL<'-1>HMC毒素处理下,Mo17-C也于7 h时达最大凋亡率,为57.3%,而Mo17-N为27.7%.[结论]在毒素"伤害"细胞致死过程中,C细胞质的细胞死亡率远高于N细胞质;在"诱导"细胞凋亡程序中,C细胞质的细胞凋亡率也远高于N细胞质的.凋亡率随诱导浓度和诱导时间的增加而增加.AO、EB复染与Hoechst 33258染色相比,两者细胞凋亡率接近,准确度均高,图像清晰,且费用相当,但前者可以区分早期和晚期凋亡细胞而后者不能区分.     

The Effect of Different Vitrification and Staining Protocols on the Visibility of the Nuclear Maturation Stage of Equine Oocytes

In this study, we compared two staining protocols assessing the nuclear chromatin stage of equine oocytes after vitrification using permeable and nonpermeable cryoprotectants. Slaughterhouse-derived oocytes (n = 155) were obtained from a total of 32 mares and in vitro matured in M199 medium for 42 hours at 38.5°C in 5% CO_2. In the first experiment, two concentrations of Hoechst 33342 (HO) were tested (10 μg/mL; P1 and 2.5 μg/mL; P2) combined with 50 μg/mL of propidium iodide as staining protocols to evaluate the visibility of matured oocytes (n = 44). In the second experiment, 111 oocytes were evaluated using the staining protocol P2, before (C, control) and after vitrification following a two-step conventional protocol with (15% dimethyl sulfoxide, 15% ethylene glycol, and 0.5 M sucrose; V1) or without (1 M sucrose; V2) using permeable cryoprotectants. Our results showed that P2 provided a higher percentage of oocytes with outstanding visibility of the nuclear chromatin stage (52.17%; P < .05) in comparison with P1 (19.04%). In the second experiment, no cryoprotectant-free vitrified oocytes reached the metaphase II maturation stage. This result was significantly lower (P < .05) than conventional vitrification (15.38%) and both lower in comparison with the nonvitrified control group (42.11%). In conclusion, permeable cryoprotectant-free vitrification of equine oocytes obtained poor results and therefore cannot be considered an alternative to vitrification using permeable cryoprotectants. In addition, a staining protocol with a low concentration of HO is recommended to evaluate the nuclear chromatin stage of equine oocytes after in vitro maturation.     

Evaluation of a side population of canine lymphoma cells using Hoechst 33342 dye

Cancer stem cell (CSC) research has increased exponentially to gain further insight into the mechanisms underlying both carcinogenesis and chemotherapy resistance. The present study was performed to explore the potential value of a side population (SP) assay for identifying and characterizing putative CSCs among canine lymphoma cells. Canine lymphoma cells from cell lines and clinical samples were subjected to the SP assay consisting of Hoechst 33342 staining and subsequent flow cytometric analysis. The SP assay revealed various amounts of a SP fraction among the canine lymphoma cells. The percentages of SP were not affected by inhibitors of membrane transporters, verapamil hydrochloride, or fumitremorgin C. Most of the canine lymphoma cells expressed high levels of Bmi-1 and membrane transporter proteins such as ABCG2 and phosphorylated (p)-glycoprotein. This investigation lays the groundwork for further studies of the biological behaviors and molecular characteristics of CSCs in cases of canine lymphoma.     

Determination of DNA content of whole fish

ABSTRACT:   The DNA content of whole fish from 31 different North Atlantic fish species was determined. Sample preparation was performed on board the fishery research vessel 'Walter Herwig III' directly after catch and sorting. Up to three homogenates were prepared of each 10 specimens per species by mincing the whole fish. The homogenates were heated to destroy nuclease activity, and then stored at frozen temperature until being analyzed in the laboratory. Measurement of DNA content was carried out using the DNA specific fluorescent dye Hoechst 33258 (Serva Biochemica, Heidelberg, Germany). Matrix effects as light scattering and quenching could be estimated by use of standard addition of calf thymus DNA. DNA contents were referred to dry weight of sample material, and ranged from 570 µg to 3500 µg/g dry weight of homogenate. The coefficient of variation did not exceed 25% of mean for one species; coefficient of variation for all investigated species did not exceed 30% of mean, which was 1020 µg/g dry weight.