Cytoplasmic localization of the interferon-inducible protein that is encoded by the AIM2 (absent in melanoma) gene from the 200-gene family

While interferons (IFNs) (alpha, beta and gamma), a family of cytokines, have the ability to exert the growth-inhibitory effect on target cells, the molecular mechanism(s) by which IFNs inhibit cell growth remains to be identified. Because IFN-inducible 'effector' proteins mediate the biological activities of IFNs, characterization of IFN-inducible proteins is critical to identify their functional role in IFN action. One family (the 200-family) of IFN-inducible proteins is encoded by structurally related murine (Ifi202a, Ifi202b, Ifi203, Ifi204 and D3) and human (IFI16, MNDA and AIM2) genes. The proteins encoded by genes in the family share a unique repeat of 200-amino acids and are primarily nuclear. The AIM2 gene is a newly identified gene that is not expressed in a human melanoma cell line. Here we report that AIM2 is estimated to be a 39 kDa protein and, unlike other proteins in the family, is localized primarily in the cytoplasm. Interestingly, overexpression of AIM2 in transfected cells retards proliferation and, under reduced serum conditions, increases the susceptibility to cell death. Moreover, AIM2 can heterodimerize with p202 in vitro. Together, these observations provide support to the idea that AIM2 may be an important mediator of IFN action.     

Novel putative photoreceptor and regulatory genes Required for the positive phototactic movement of the unicellular motile cyanobacterium Synechocystis sp. PCC 6803

Synechocystis: sp. PCC 6803 is a unicellular motile cyanobacterium, which shows positive or negative phototaxis on agar plates under lateral illumination. By gene disruption in a substrain showing of positive phototaxis, it was demonstrated that mutants defective in sll0038, sll0039, sll0041, sll0042 or sll0043 lost positive phototaxis but showed negative phototaxis away from the light source. Mutants of sll0040, which is located within the cluster of these genes, retained the capacity of positive phototaxis but to a lesser extent than the parent cells. These genes are homologous to che genes, which are involved in flagellar switching for bacterial chemotaxis. Interestingly, sll0041 (designated pisJ1) is predicted to have a chromophore-binding motif of phytochrome-like proteins and a signaling motif of chemoreceptors for bacterial chemotaxis. It is strongly suggested that the positive phototactic response was mediated by a phytochrome-like photoreceptor and CheA/CheY-type signal transduction system.     

Propagation of potato tubers in a nutrient mist bioreactor

The newly designed nutrient mist bioreactor provided an environment supporting multiple-layer culture. In vitro tubers of potato (Solanum tuberosum L.) were induced and cultured in this bioreactor by using two culture methods. The percentage of the inocula eventually forming tubers in a two-step method was 98% with only 54% being formed in a one-step method. The two-step method improved the efficiency of tuber induction, expedited and synchronized the tuberization. © Rapid Science Ltd. 1998     

天敌对麦长管蚜和麦二叉蚜种群数量影响程度的分析

通过对１９９３～１９９６年两种麦蚜种群数量及其天敌数量的系统调查,并采用灰色关联分析法,研究各种天敌对两种麦蚜种群数量的影响程度,得出对麦长管蚜种群数量影响最大的是龟纹瓢虫、蚜茧蜂和食蚜蝇;对麦二叉蚜种群数量影响最大的是草间小黑蛛,其次是龟纹瓢虫．     

精制白喉毒素脱毒工艺的改进

为了改进精制白喉毒素脱毒工艺中存在的时间长和损失大等问题,我们考虑进行脱毒过程中加入Ｌ－赖氨酸协同脱毒的试验,并以原工艺进行比较,结果使原工艺存在的问题均得到较好的解决。     

抗HIV-1 gp160独特型阳性抗体的序列分析及表达

为了确定从噬菌体抗体文库中筛选出的抗体的属性和方便目的基因的表达及其产物的纯化,对两株具有“１Ｆ７”独特型的抗ＨＩＶ－１ｇｐ１６０抗体基因进行了序列分析并构建了可溶性表达载体．发现３Ｂ株含有完整的Ｆａｂ段,１Ｄ株只有重链Ｆｄ段．序列测定表明两株克隆的Ｆｄ段基因完全相同,其可变区ＶＨ属于ＶＨⅠ亚群,而３Ｂ株的“轻链”序列与已知的人的κ和λ轻链无同源性．用从另外的Ｆａｂ抗体文库中筛选出来的３株抗乙肝表面抗原抗体的轻链与３Ｂ的重链重组,并选择一个ＨＩＶ－１ｇｐ１６０特异性较好的重组抗体株,命名为３Ｂｓ．构建了１Ｄ株与３Ｂｓ株的可溶性表达载体,免疫印迹实验证实了具有“１Ｆ７”独特型的抗ｇｐ１６０独特型阳性抗体的表达．     

噬菌体抗体文库的构建及人源抗HIV-1 gp 160抗体的筛选

构建人源噬菌体抗体文库如下：ＨＩＶ感染者脾细胞中提取ｍＲＮＡ,经反转录再以人ＩｇＧ重链Ｆｄ两端及轻链“通用”引物分别扩增Ｆａｂ基因片段,依次插入到噬菌粒载体ｐＣｏｍｂ３中,电转化大肠杆菌ＸＬ１－Ｂｌｕｅ,经辅助噬菌体救助,重组噬菌体得以溶源裂解,Ｆａｂ表达于噬菌体包膜蛋白Ⅲ的Ｎ端．此噬菌体抗体库的容量为５×１０５．筛选抗ＨＩＶ－１同时又具有能被抗独特型抗体“ＩＦ７”所识别的独特型的阳性抗体：以重组包膜糖蛋白ｇｐ１６０及ｇｐ４１多肽对噬菌体抗体文库进行三次淘选,使抗ｇｐ１６０的特异性抗体得到１００倍的富集．然后通过直接ＥＬＩＳＡ和竞争性ＥＬＩＳＡ实验筛选出两株结合性较好的特异性抗ｇｐ１６０抗体－３Ｂ株与１Ｄ株．直接ＥＬＩＳＡ实验表明这两株克隆均能被“１Ｆ７”所识别,为抗独特型多肽的筛选奠定了基础．     

枳壳外植体离体再生及农杆菌介导的遗传转化

以枳壳实生苗的上胚轴及茎段为材料,在附加有ＢＡ和ＭＴ培养基上进行培养,上胚轴出芽率普遍高于茎段,ＢＡ为１ｍｇ／Ｌ时,出芽率最高,ＢＡ浓度升高,出芽率随之下降。外植体在培养基上的接种方式,对出芽有一定影响,上胚轴切段 形态学下端垂直插入,出芽率高。     

Design and synthesis of 4-[3,5-dioxo-11-oxa-4,9-diazatricyclo[5.3.1.02,6]undec-4-yl]-2-trifluoromethyl-benzonitriles as androgen receptor antagonists

A novel series of 4-[3,5-dioxo-11-oxa-4,9-diazatricyclo[5.3.1.0^2,6]undec-4-yl]-2-trifluoromethyl-benzonitriles has been synthesized. The ability of these compounds to act as antagonists of the androgen receptor was investigated and several were found to have potent activity in vitro and in vivo.     

Contact Toxicity and Repellency of the Essential Oil from Mentha haplocalyx Briq. against Lasioderma serricorne

The chemical composition of the essential oil obtained by hydrodistillation from the aerial parts of Mentha haplocalyx was investigated by GC‐FID and GC/MS analyses. In sum, 23 components, representing 92.88% of the total oil composition, were identified, and the main compounds were found to be menthol (59.71%), menthyl acetate (7.83%), limonene (6.98%), and menthone (4.44%). By bioassay‐guided fractionation (contact toxicity), three compounds were obtained from the essential oil and identified as menthol, menthyl acetate, and limonene. The essential oil and the three isolated compounds exhibited potent contact toxicity against Lasioderma serricorne adults, with LD₅₀ values of 16.5, 7.91, 5.96, and 13.7 μg/adult, respectively. Moreover, the oil and its isolated compounds also exhibited strong repellency against L. serricorne adults. At the lower concentrations tested and at 2 h after exposure, menthol showed even significantly stronger repellency than the positive control DEET. The study revealed that the bioactivity properties of the essential oil can be attributed to the synergistic effects of its diverse major and minor components, which indicates that the M. haplocalyx oil and its isolated compounds have potential for the development as natural insecticides and/or repellents to control insects in stored grains and traditional Chinese medicinal materials.