Isolation of chicken embryonic stem cell and preparation of chicken chimeric model

Chicken embryonic stem cells (ESCs) were separated from blastoderms at stage-X and cultured in vitro. Alkaline phosphatase activity and stage-specific embryonic antigen-1 staining was conducted to detect ESCs. Then, chicken ESCs were transfected with linearized plasmid pEGFP-N1 in order to produce chimeric chicken. Firstly, the optimal electrotransfection condition was compared; the results showed the highest transfection efficiency was obtained when the field strength and pulse duration was 280 V and 75 μs, respectively. Secondly, the hatchability of shedding methods, drilling a window at the blunt end of egg and drilling a window at the lateral shell of egg was compared, the results showed that the hatchability was the highest for drilling a window at the lateral shell of egg. Thirdly, the hatchability of microinjection (ESCs was microinjected into chick embryo cavity) was compared too, the results showed there were significant difference between the injection group transfected with ESCs and that of other two groups. In addition, five chimeric chickens were obtained in this study and EGFP gene was expressed in some organs, but only two chimeric chicken expressed EGFP gene in the gonad, indicating that the chimeric chicken could be obtained through chick embryo cavity injection by drilling a window at the lateral shell of egg.     

化学调控剂对水稻不育系育性恢复效应的研究

１９９２年３月至１１月,我们在海南和长沙两地,先后使用３８种化学调控剂,对水稻两用不育系,三系不育系及普通核不育系进行了喷施和注射试验,筛选出７种较为有效的调控剂,代号为ＣＲ１—ＣＲ７,其中ＣＲ５和ＣＲ７表现较为突出。这些调控剂对两用不育系和三系不育系均表现出一定程度的恢复效应,且ＣＲ１和ＣＲ２还能在可育条件下提高培矮６４Ｓ的结实率,但所有调控剂对普通核不育系均无恢复作用。     

Optimization of novel monobactams with activity against carbapenem-resistant Enterobacteriaceae – Identification of LYS228

Metallo-β-lactamases (MBLs), such as New Delhi metallo-β-lactamase (NDM-1) have spread world-wide and present a serious threat. Expression of MBLs confers resistance in Gram-negative bacteria to all classes of β-lactam antibiotics, with the exception of monobactams, which are intrinsically stable to MBLs. However, existing first generation monobactam drugs like aztreonam have limited clinical utility against MBL-expressing strains because they are impacted by serine β-lactamases (SBLs), which are often co-expressed in clinical isolates. Here, we optimized novel monobactams for stability against SBLs, which led to the identification of LYS228 (compound 31). LYS228 is potent in the presence of all classes of β-lactamases and shows potent activity against carbapenem-resistant isolates of Enterobacteriaceae (CRE).     

Persistent tetrodotoxin-resistant Na+ currents are activated by prostaglandin E2 via cyclic AMP-dependent pathway in C-type nodose neurons of adult rats

It has been documented that nodose neurons express TTX-sensitive (TTX-S) and TTX-resistant (TTX-R) Na(+) channels. However, wheteher nodose neurons functionally express persistent TTX-R Na(+) currents has not been reported. The present study first demonstrated persistent TTX-R Na(+) channel activities in 7/19 C-type nodose neurons in the presence of PGE(2) using whole-cell patch. Voltage-dependent property showed that persistent TTX-R Na(+) currents were activated at near -60mV and channels were maintained open. The average peak was approximately 300-500pA. The mid-point of activation exhibited a greater shift to a more hyperpolarized potential in the neurons co-expressing TTX-R and persistent TTX-R Na(+) currents than those expressing TTX-R only. This effect of PGE(2) was also mimicked by Forskolin. The fact that persistent TTX-R Na(+) currents were only activated by PGE(2) suggested that the modulatory effects of PGE(2) on persistent TTX-R Na(+) currents are crucial in PGE(2)-mediated neuronal excitability, and may have a great impact on specifically physiological significance.     

Gene conjugation of molecular adjuvant C3d3 to hCGbeta increased the anti-hCGbeta Th2 and humoral immune response in DNA immunization

Human chorionic gonadotropin (hCG) has been used as an anti-fertility vaccine and as a target for cancer immunotherapy. We have explored the use of three copies of C3d in DNA vaccine as molecular adjuvant to improve the immunogenicity of this hormone in previous work and found that the immune response induced by pcDNA3-hCGbeta-C3d3 has been enhanced 243-fold compared with pcDNA3-hCGbeta following DNA immunization in BALB/c mice. In the present study, a new functionally active DNA vaccine of hCGbeta-C3d3 chimera based on pCMV4 vector has been described. We compared the expression efficiency of pCMV4 and pcDNA3 eukaryotic vectors for hCGbeta and hCGbeta-C3d3 fusion protein and the immune response of mice immunized with pcDNA3-hCGbeta, pCMV4-hCGbeta, pcDNA3-hCGbeta-C3d3 and pCMV4-hCGbeta-C3d3, respectively, at 25, 50 and 100 pmol dose, and further analyzed the levels of Th1 and Th2 cytokines produced by spleen lymphocytes of the immunized mice upon hCG restimulation in vitro. It was found that pCMV4 vector achieved 1.3-1.5-fold higher protein expression and raised 1.1-1.2 (primary) and 1.2-1.3 (booster) logs higher titer of anti-hCGbeta IgG than pcDNA3. Mice vaccinated with 50 pmol of hCGbeta-C3d3-DNAs elicited the highest titer of hCGbeta-specific antibody among the serial doses and the immune response induced by pCMV4-hCGbeta-C3d3 were, respectively, 1.3, 1.3 and 1.2 logs higher than that of pcDNA3-hCGbeta-C3d3 and 2.2, 2.9 and 2.4 logs higher than that of pCMV4-hCGbeta at week 2 following the booster immunization. Moreover, we observed that the production of IL-4 and IL-10 increased in mice vaccinated with hCGbeta-C3d3-DNAs and the ratio of IL-4/IFN-(gamma) showed a Th2 bias of immune response in the mice immunized with hCGbeta-C3d3-DNAs. These findings indicated that gene fusion of C3d3 to hCGbeta, as a means of harnessing the adjuvant potential of the innate immune system, may improve the antigen-specific Th2 humoral immune response of the hCGbeta DNA vaccine and the pCMV4 vector is a more ideal eukaryotic vector for DNA vaccine than pcDNA3.     

‘勐海大叶茶’种子萌发特性

以大叶茶品种‘勐海大叶茶’ （Camellia sinensis var. assamica cv. Menghai Dayecha） 种子为材料,进行种子萌发特性的初步研究。研究发现,种皮对‘勐海大叶茶’种子的萌发存在一定的作用,含水量较高时,人为破除种皮有助于种子的萌发,随着含水量的降低,人为破除种皮反而降低了种子的萌发率。‘勐海大叶茶’种子的最适萌发温度为30℃,15℃以下时萌发率较低,容易发生低温伤害,变温处理对提高种子萌发率的效果不明显。基质对大叶茶种子萌发的影响不明显,四种不同种植基质条件下,种子的萌发率趋于相同水平,证明基质类型并非影响种子萌发的关键因子。     

融合基因umcel5N-CBM的构建、表达及融合酶性质分析

BM,并实现了融合基因在大肠杆菌BL21(DE3)pLysS中的表达.研究结果表明,融合酶Umcel5N-CBM与结晶纤维素(avicel)以及滤纸粉末的结合能力比原始酶Umcel5N提高了约一倍,但未显示出降解结晶纤维素的新活性,说明在结晶纤维素的降解过程中,纤维素酶的催化功能域起到关键作用.     

昆虫体内储存蛋白的研究进展

储存蛋白是昆虫体内普遍存在的一种特异性血淋巴蛋白 ,通常在幼虫的脂肪体内合成 ,释放进入血淋巴中。化蛹时 ,又被脂肪体选择性吸收 ,作为氨基酸的贮存库对成虫变态发育和雌性卵发育起着重要的作用。该文介绍了昆虫体内储存蛋白的特性、功能、及调节机制。