Initial detection of the quorum sensing autoinducer activity in the rumen of goats in vivo and in vitro

Quorum sensing(QS) is a type of microbe-microbe communication system that is widespread among the microbial world, particularly among microorganisms that are symbiotic with plants and animals. Thereby, the cell-cell signalling is likely to occur in an anaerobic rumen environment, which is a complex microbial ecosystem. In this study, using six ruminally fistulated Liuyang black goats as experimental animals, we aimed to detect the activity of quorum sensing autoinducers(AI) both in vivo and in vitro and to clone the lux S gene that encoded autoinducer-2(AI-2) synthase of microbial samples that were collected from the rumen of goats. Neutral detergent fiber(NDF) and soluble starch were the two types of substrates that were used for in vitro fermentation. The fermented fluid samples were collected at 0, 2, 4, 6, 8, 12, 24, 36, and 48 h of incubation. The acyl-homoserine lactones(AHLs) activity was determined using gas chromatography-mass spectrometer(GC-MS) analysis. However, none of the rumen fluid extracts that were collected from the goat rumen showed the same or similar fragmentation pattern to AHLs standards. Meanwhile, the AI-2 activity, assayed using a Vibrio harveyi BB170 bioassay, was negative in all samples that were collected from the goat rumen and from in vitro fermentation fluids. Our results indicated that the activities of AHLs and AI-2 were not detected in the ruminal contents from six goats and in ruminal fluids obtained from in vitro fermentation at different sampling time-points. However, the homologues of lux S in Prevotella ruminicola were cloned from in vivo and in vitro ruminal fluids. We concluded that AHLs and AI-2 could not be detected in in vivo and in vitro ruminal fluids of goats using the current detection techniques under current dietary conditions. However, the microbes that inhabited the goat rumen had the potential ability to secrete AI-2 signaling molecules and to communicate with each other via AI-2-mediated QS because of the presence of lux S.     

An opiate binding site in the rat brain is highly selective for 4,5-epoxymorphinans

In vitro binding studies have demonstrated the existence of multiple opiate receptor types. An additional site in the rat brain (termed the lambda site) is distinct from the established types by its selectivity for 4,5-epoxymorphinans (such as naloxone and morphine). While the lambda site displays a high affinity for naloxone in vivo and in vitro in fresh brain membrane homogenates, these sites rapidly convert in vitro to a state of low affinity. The regional distribution of the lambda site in the brain is strikingly different from that of the classic opiate receptor types.     

小鼠受精卵在体内外发育成桑椹胚的对比研究

用１０单位孕马血清和１０单位人绒毛膜促性腺素使小白鼠超数排卵,自然交配后分两组,一组取受精卵,统计受精卵个数,并在ＣＺＢ培养基微滴内培养７８ｈ,统计发育成又桑椹胚的个数。另一组,让受精卵在体内自然发育７２ｈ,收集桑椹胚,统计其个数。比较研究受精卵在体内外发育到桑椹胚的能力。实验结果表明,每只鼠的平均冲出受精卵数为２８．２枚;受精诳在体外培养时桑椹胚的发育率为８８％;因此在体外培养时从每只鼠平均可得     

Leukotactic factor produced by sensitized lymphocytes

Lymph node lymphocytes obtained from guinea pigs exhibiting delayed hypersensitivity are stimulated in vitro by specific antigen to produce a soluble factor that is chemotactic in vitro for mononuclear macrophages. The material is nondialyzable, relatively heat stable, and elutes from Sephadex G-100 in the fraction containing molecules smaller than immunoglobulins.     

Reversal of knob formation on Plasmodium falciparum-infected erythrocytes

The human malarial parasite Plasmodium falciparum can produce surface protrusions (knobs) on infected erythrocytes; however, long-term culturing of the parasite results in the appearance of knobless cells. In this study it was found that a knob-producing clone lost the ability to produce knobs in vitro. Furthermore, a clone not producing knobs derived from the knob-producing clone regained the capacity to produce knobby cells in vitro. Certain parasite proteins were associated with the knobby phenotype but not with the knobless type. These results indicate that the parasites change in vitro in a spontaneous and reversible manner independent of immunological selection.     

山羊卵泡卵母细胞的采集与体外成熟研究

为了建立针对山羊卵母细胞的理想体外成熟培养体系,研究了山羊卵泡卵母细胞的采集方法和采集获得的可用卵母细胞的体外成熟培养条件,结果表明:切割法能够获得较多的可用卵母细胞,且明显增加了用于体外成熟的卵母细胞数;卵母细胞在37.0℃下培养的成熟率显著低于在38.5℃、39.0℃下培养的成熟率(P＜0.05);卵母细胞培养18 h和培养20h的成熟率极显著低于培养24 h和培养26 h的成熟率(P＜0.01);此外,卵母细胞体外成熟培养时,培养液中的胎牛血清添加量以10%～15%为宜.     

氧分压对猪卵母细胞成熟尧受精及早期胚胎发育的影响

研究利用两种氧分压（5%和20%）培养卵母细胞并进行IVF试验,同时使用两种氧分压培养孤雌（PA）胚胎、体外受精（IVF）胚胎和克隆(NT) 胚胎,以探寻猪的最佳体外培养环境。结果显示：低氧分压不利于猪卵母细胞的体外成熟,其成熟率极显著低于高氧培养的,但对低氧培养的卵母细胞进行IVF时,其卵裂率和囊胚率均极显著高于高氧培养的卵母细胞;IVF进行精卵孵育时,低氧环境下,其胚胎卵裂率和囊胚率均显著高于高氧环境下的;PA胚胎、IVF胚胎和NT胚胎用两种氧分压培养,低氧条件下IVF胚胎的发育能力高于高氧培养的,而PA胚胎和NT胚胎差异不显著。试验结果表明,低氧培养虽不利于卵母细胞的成熟,但有利于其以后的胚胎发育,且低氧环境下IVF胚胎的发育能力高于高氧环境下的。     

百合不同离体授粉方法的杂交结实研究

为克服百合(Lilium ssp.)杂交受精前障碍,以5个杂种系品种和1个野生种为试材,采用离体柱头授粉、高体切割花柱授粉和离体子房授粉方法进行离体授粉杂交.结果显示,对于近缘杂交,离体柱头授粉的子房膨大率和结实率分别为30%和15%,高体切割花柱授粉的为15%和5%,离体子房授粉的为25%和5%;不同杂种系间杂交组合3种授粉方法的子房膨大率和结实率分别为17%和13%、3%和3%、10%和3%.百合杂交组合类型对高体授粉杂交结实率有明显影响;近缘杂交或系内杂交组合的子房膨大率和结实率高于远缘杂交(系间杂交)组合.在3种离体授粉方法中以高体柱头授粉的效果最好,其余2种方法的效果基本相同.采用胚培救方法获得了部分杂交组合的幼苗,经ISSR分子标记鉴定了杂种的真实性,表明通过离体授粉方法可以获得百合远缘杂交的真实杂种.     

枇杷叶黄酮的提取及对小鼠的抗氧化作用

旨在研究枇杷叶黄酮的体内外抗氧化作用。用微波提取方法提取黄酮,使用丙二醛(MDA)测定试剂盒测定枇杷叶黄酮对体内外MDA质量浓度影响;用分光光度法测定枇杷叶黄酮对H₂O₂诱导小鼠红细胞溶血,羟自由基测定试剂盒测定体内外血清中羟自由基,并计算DPPH自由基清除率。结果表明,枇杷叶黄酮质量浓度为0.05~4.00 g/L时具有较强的体外抗氧化能力,并能减少小鼠肝线粒体及肝匀浆MDA的生成,可抑制H₂O₂诱导的小鼠红细胞溶血;腹腔注射枇杷叶黄酮对小鼠体内肝组织MDA生成的抑制作用显著。枇杷叶黄酮具有较强的体内外抗氧化作用。     

波尔山羊活体采卵与卵母细胞体外受精技术

对10只不孕不育波尔母山羊采用超数排卵、活体采卵、卵母细胞体外成熟培养以及体外受精等技术方法,探讨其是否能正常繁育后代。试验中6只供体经超数排卵处理,在发情前利用特制的采卵装置进行活体采卵,共采集到30枚形态学正常的卵母细胞。经过体外成熟培养,有21枚成熟卵母细胞进行了体外受精处理和培养,获得16枚2 细胞胚胎,移植到4只同期发情的当地山羊受体输卵管内,经妊娠检验,有两只受体受孕,其中1只受体产出正常羔羊2只。该技术经进一步改进完善后可望作为不孕不育波尔山羊繁殖后代的辅助生育技术。     

Human leukemic cells: in vitro growth of colonies containing the Philadelphia (Ph) chromosome

Human leukemic cells with a marker (Philadelphia; Ph(1)) chromosome gave rise to granulocytic and mononuclear cell colonies when grown in vitro. All metaphases from a single colony were either Ph(1) positive or Ph(1) negative. No colonies contained a mixed cell population. This suggests that leukemic and normal cells exist simultaneously and that in vitro colonies are clonal in origin.     

Prediction of chemical carcinogenicity in rodents from in vitro genetic toxicity assays

Four widely used in vitro assays for genetic toxicity were evaluated for their ability to predict the carcinogenicity of selected chemicals in rodents. These assays were mutagenesis in Salmonella and mouse lymphoma cells and chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells. Seventy-three chemicals recently tested in 2-year carcinogenicity studies conducted by the National Cancer Institute and the National Toxicology Program were used in this evaluation. Test results from the four in vitro assays did not show significant differences in individual concordance with the rodent carcinogenicity results; the concordance of each assay was approximately 60 percent. Within the limits of this study there was no evidence of complementarity among the four assays, and no battery of tests constructed from these assays improved substantially on the overall performance of the Salmonella assay. The in vitro assays which represented a range of three cell types and four end points did show substantial agreement among themselves, indicating that chemicals positive in one in vitro assay tended to be positive in the other in vitro assays.     

瘦素对水牛卵母细胞体外成熟和体外受精胚胎发育的影响

[目的]探讨瘦素在水牛体外胚胎生产体系中的作用机理,提高体外胚胎生产效率,为利用分离精子加速水牛品种改良及良种群的扩繁奠定基础.[方法]分别在水牛卵母细胞成熟培养液和胚胎培养液中添加瘦素,研究其对水牛卵母细胞体外成熟率和体外受精胚胎发育率的影响.[结果]在水牛卵母细胞体外成熟液阶段,添加瘦素不仅能促成熟,还能提高其胚胎发育潜能;在体外受精后的胚胎培养阶段,添加瘦素也能显著提高囊胚发育率,二者的最佳瘦素浓度均为10 ng/mL.在最佳瘦素浓度(10 ng/mL)下,常规精子体外受精后的囊胚发育率从19.7%(空白对照组)提高到27.0%,分离精子体外受精后的囊胚发育率从12.3%(空白对照组)提高到17.4%.[结论]瘦素能促进水牛卵母细胞体外成熟及体外受精胚胎发育,并以添加10 ng/mL瘦素的促进效果最明显.     

苹果组培苗和温室盆栽苗对火疫病的感病性研究

不同品种的苹果对梨火疫病（Erwinia amylovora）菌的敏感性不同，用盆栽苗与体外组培苗所得的结果一致，感病快的品种体内所含的病菌数高于感病慢的品种；外植体的生理状态对病害的发生有影响。     

高原农作物豌豆抗氧化和脂质过氧化研究

1材料与方法 1．1材料供试豌豆产于西宁互助,海拔3600m;供试小鼠体重18-22g,雌雄对半,由青海动物养殖场提供。     

Growth in vitro of cells from hyperplastic nodules of liver induced by 2-fluorenylacetamide or aflatoxin B1

Cell suspensions obtained from hyperplastic nodules induced in rat liver by either of the two hepatic carcinogens, 2-fluorenylacetamide or aflatoxin B(1), show growth when cultured in vitro. No growth of cells from liver adjacent to the hyperplastic nodules or from liver of control rats has been obtained so far under comparable conditions. Hepatocarcinoma cells induced by 2-fluorenylacetamide grow readily in vitro but behave differently. These findings suggest that some nonmalignant cells capable of growth in vitro arise during liver carcinogenesis prior to the appearance of unequivocal cancer. Cultures of such cells may offer new avenues for the study of liver carcinogenesis.     

常绿阔叶杂交杜鹃组培体系的建立

常绿阔叶杂交杜鹃具有较高的观赏价值和园林利用价值，因而建立组培快繁体系具有重要意义。对8个材料的组培快繁研究结果表明，茎段外植体均能诱导萌发，平均诱导率达到75．2％，平均增殖系数达到5～6倍；以WPM为继代培养基的组培苗枝条粗壮、叶色深绿，优于Anderson、Read培养基；继代培养过程中的ZT浓度以0．5～1．0mg／L，pn值以4．8～5．2较为适宜；通过瓶外扦插生根方法获得了大量组培苗，其平均生根率达到76％左右，从而建立了常绿阔叶杂交杜鹃组培快繁体系。     

LH Plays a Role to Enhance the Nuclear and Cytoplasm Synchronization During In vitro Maturation of Ovine Oocytes

This study is aimed to investigate the effect of luteinizing hormone (LH) on maturation and fertilization in vitro of ovine oocytes.The ovine oocytes were cultured in vitro in medium with or without LH,and then checked by confocal laser scanning microscope to observe the distribution of cortical granules stained with FITC-LCA during different maturation periods.Similarly,some in vitro matured oocytes were also fertilized in vitro for analysis of their developmental potentiality further.After being cultured in vitro for 4 h,there were significant differences about the rate of germinal vesicle break down (GVBD) between the treatment (with LH) and the control groups (without any hormones) (36.76% vs 18%,P<0.05).Further,there were also significant differences of the cleavage and blastocyst rates between these two groups (67.15% vs 42.37%,21.9% vs 12.71%,P<0.05,respectively).The distribution of cortical granules appeared to spread from the edges to the central site of sheep oocytes following their delaying durations of maturation in vitro.It can be concluded that LH may play a role to delay the occurence of GVBD,prolong the maturation duration of cytoplasm,and enhance the nuclear and cytoplasm synchronization of ovine oocytes matured in vitro and finally improve their in vitro developmental potentiality.     

程序化冷冻对小鼠胚胎发育的影响

取小鼠原核(220枚)、2～4细胞胚胎(227枚)、桑椹胚(127枚),将其分为3组,每一时期胚胎分成两半,一半取出后立即冷冻复苏并体外培养至囊胚,另一半体外培养至囊胚后冷冻复苏,子宫冲取囊胚(78枚)冷冻复苏为对照组;各组囊胚均移植至于宫,比较程序化冷冻对小鼠早期胚胎存活率的影响.结果表明:原核、2～4细胞胚胎、桑椹胚体外培养至囊胚后冷冻复苏率分别为56.4%、72.2%、81.6%,移植产仔率分别为38.1%、41.6%、56.8%,原核、2～4细胞组复苏率和产仔率极显著或显著低于对照组,桑椹胚组与对照组差异不显著,显示体外培养对早期胚胎冷冻存活有影响;原核、2～4细胞胚胎、桑椹胚冷冻后体外培养至囊胚,胚胎移植后产仔率分别为25.3%、28.2%、42.1%,与对应胚胎时期体外培养至囊胚冷冻复苏后移植产仔率相比,原核、2～4细胞组均存在显著差异,而桑椹胚组差异不显著,显示原核、2～4细胞的早期胚胎体外培养至囊胚后冷冻可提高冷冻存活率.