Changes in blood leukocytes,bone marrow and lymphoid organs in sheep infected with Haemonchus contortus

Haemonchus contortus infection, which causes a blood loss anaemia in sheep, depleted leukocytes and produced leukopenia and a mild lymphopenia. Thymus atrophy, a decreased size of spleen and enlargement of adrenal glands occurred concomitantly in infected sheep which suggested that they were caused by the stress of infection. The overwhelming change in bone marrow of infected sheep was a 4-fold increase in erythroid series cells.Primary immunization with rat erythrocytes produced similar haemagglutinating antibody responses in infected sheep and in sheep allowed to recover from infection after treatment with thiabendazole. This suggests that extant infection with H. contortus was not associated with a secondary immunodeficiency. Blastogenic responses of blood lymphocytes from infected sheep to larval antigen correlated with faecal egg counts but not with haematocrit or leukocyte values. These results suggest that the unresponsiveness of lymphocytes to worm antigen which occur during infection with H. contortus is more closely related to contact with the parasite than to the pathological effects of infection.     

提高农杆菌基因转化率方法的研究

通过甘蓝型油菜带柄子叶转化过程中转化受体是否进行预培处理、转化前菌液的对数浓度确定以及合适的再生筛选体系的摸索,研究了提高农杆菌基因转化效率的方法。试验结果表明：转化受体经过MD培养基3d的预培处理,用处于对数生长期OD600为0．6～0．8的菌液稀释至所需浸染浓度,浸染所需时间共培后,转入降低卡那霉素浓度的初筛分化培养基中,再经过后期较高浓度的卡那霉素继代筛选培养,大大提高了转化后卡那霉素抗性绿苗的得率。此研究不仅优化了油菜的转化体系和提高了油菜的转化效率,而且为农杆菌转化其它不同物种的受体材料提供了可指导的借鉴。     

紫杉醇替代资源研究进展

紫杉醇是近30年来从植物中筛选出的首选抗癌药物,已被美国的FDA批准治疗晚期卵巢癌和转移性乳腺癌。由于资源奇缺已出现严重供给危机。本文综述了近3年来紫杉醇替代资源研究的新进展,主要包括组织培养、遗传转化、化学合成和紫杉霉等方面的新成就。     

Cloning and expression of a Xenopus gene that prevents mitotic catastrophe in fission yeast

In fission yeast the Weel kinase and the functionally redundant Mikl kinase provide a regulatory mechanism to ensure that mitosis is initiated only after the completion of DNA synthesis. Yeast in which both Weel and Mik1 kinases are defective exhibit a mitotic catastrophe phenotype, presumably due to premature entry into mitosis. Because of the functional conservation of cell cycle control elements, the expression of a vertebrate weel or mikl homolog would be expected to rescue such lethal mutations in yeast. A Xenopus total ovary cDNA library was constructed in a fission yeast expression vector and used to transform a yeast temperature-dependent mitotic catastrophe mutant defective in both weel and mikl. Here we report the identification of a Xenopus cDNA clone that can rescue several different yeast mitotic catastrophe mutants defective in Weel kinase function. The expression of this clone in a weel/mikl-deficient mutant causes an elongated cell phenotype under non-permissive growth conditions. The 2.0 kb cDNA clone contains an open reading frame of 1263 nucleotides, encoding a predicted 47 kDa protein. Bacterially expressed recombinant protein was used to raise a polyclonal antibody, which specifically recognizes a 47 kDa protein from Xenopus oocyte nuclei, suggesting the gene encodes a nuclear protein in Xenopus. The ability of this cDNA to complement mitotic catastrophe mutations is independent of Weel kinase activity.     

Efficient genetic transformation and CRISPR/Cas9‐mediated genome editing in Lemna aequinoctialis

The fast growth, ease of metabolic labelling and potential for feedstock and biofuels production make duckweeds not only an attractive model system for understanding plant biology, but also a potential future crop. However, current duckweed research is constrained by the lack of efficient genetic manipulation tools. Here, we report a case study on genome editing in a duckweed species, Lemna aequinoctialis, using a fast and efficient transformation and CRISPR/Cas9 tool. By optimizing currently available transformation protocols, we reduced the duration time of Agrobacterium‐mediated transformation to 5–6 weeks with a success rate of over 94%. Based on the optimized transformation protocol, we generated 15 (14.3% success rate) biallelic LaPDS mutants that showed albino phenotype using a CRISPR/Cas9 system. Investigations on CRISPR/Cas9‐mediated mutation spectrum among mutated L. aequinoctialis showed that most of mutations were short insertions and deletions. This study presents the first example of CRISPR/Cas9‐mediated genome editing in duckweeds, which will open new research avenues in using duckweeds for both basic and applied research.     

Intracellular levels of calmodulin are increased in transformed cells

By using Hoechst 33342,rabbit anti calmodulin antibody,FITC-labeled goat anti rabbit IgG and SR101(sulfo rhodamine 101)simultaneously to stain individual normal and transformed cells,the microspectrophotometric analysis demonstrated that 3 markers which represented the nucleus,calmodulin and total protein respectively,could be recognized in individualj cells without interference,The phase of the cell cycle was determined by DNA content(Hoechst 33342),We found that in transformed cells(NIH3T3) tsRSV-LA90,cultured at 33℃ and transformed C3H10T1/2 Cells),the ration of calmodulin to total protein (based on the phases of cell cycle)was higher than that in normal cells (NIH3T3 tsRSV-LA90 cells,cultured at 39℃ and C3H10T1/2 cells)in every cell cycle phase,This ration increased obviously only from G1 to S phase in either normal or transformed cells.The results showed that calmodulinreally increased during the transformation,and its increase was specific.In the meantime when cells proceeded from G1 to S.the intraceollular calmodulin content also increased specifically.     

桉树胚状体再生与遗传转化的研究进展

文章综述了桉树胚状体发生过程中基因型、外植体材料、培养基、光照、植物生长调节剂种类与配比以及其他添加物对外植体胚性愈伤组织诱导以及胚状体发生的影响,探讨了影响桉树遗传转化体系建立的因素,并对近年来桉树胚状体再生和转基因研究进展进行了介绍。     

comE基因缺陷影响肺炎链球菌体内诱导基因的表达

【目的】筛选受comE调控的肺炎链球菌(Streptococcus pneumoniae,S.pn)体内诱导基因。【方法】通过插入失活构建基因comE缺陷的S.pn菌株,与野生菌株分别腹腔注射BALB/c小鼠,经过体内诱导后取小鼠血,分离细菌提取RNA,用RT-PCR法检测13个体内诱导基因mRNA水平差异。【结果】将RT-PCR结果通过Quantity-one灰度分析,进行配对t检验,显示8个体内诱导基因在缺陷菌株和野生菌株中mRNA表达水平具有统计学差异(P0.05),其中spd-0300、spd-0414、spd-0622、spd-1663、spd-1719、spd-0235、spd-0873受转化上调,spd-1672受转化下调。【结论】筛选出受转化调控的体内诱导基因spd-0300、spd-0414、spd-0622、spd-1663、spd-1719、spd-0235、spd-0873、spd-1672,它们可能参与生长调节、温度感应、糖脂代谢等环节,表明细菌转化可通过调节某些体内诱导基因的表达来增强细菌的毒力。