【目的】果蝇是完全变态昆虫,蛹期经历了幼虫组织解离和成虫组织重塑的过程。本研究旨在利用细胞谱系追踪方法 G-TRACE(Gal4 technique for real-time and clonal expression)这一新的遗传学技术,检测果蝇幼虫后肠肠细胞在蛹期发育过程...【目的】果蝇是完全变态昆虫,蛹期经历了幼虫组织解离和成虫组织重塑的过程。本研究旨在利用细胞谱系追踪方法 G-TRACE(Gal4 technique for real-time and clonal expression)这一新的遗传学技术,检测果蝇幼虫后肠肠细胞在蛹期发育过程中是否发生细胞迁移。【方法】采用黑腹果蝇Drosophila melanogaster engrailed-Gal4(en-Gal4)品系和G-TRACE品系杂交,并引入tub-gal80ts控制Gal4的开启时间,分别在果蝇幼虫期和蛹期进行细胞谱系追踪。幼虫期追踪:亲代产卵后将卵置于30℃培养,3龄中期转入18℃培养,成虫羽化1 d内进行检测。蛹期追踪:亲代产卵后将卵置于18℃培养,在蛹期不同发育阶段转入30℃培养,待虫体羽化后检测成虫肠道。【结果】当在果蝇幼虫期启动细胞谱系追踪,在蛹期停止追踪,发现中肠靠近中后肠边界处以及马氏管存在绿色肠细胞。而当在果蝇幼虫期关闭细胞谱系追踪,在蛹期开始追踪,则发现虫体中肠各部位及马氏管分布着绿色肠细胞。en基因在果蝇蛹期肠道中表达。【结论】结果表明,在果蝇蛹形成过程中,后肠的部分肠细胞迁移至中肠和马氏管,参与中肠和马氏管的重塑。本研究对于探索昆虫在变态发育过程中成虫器官的重塑机制具有重要的意义。展开更多
β2肾上腺素受体(β2adrenergic receptor,β2AR)是G蛋白耦联受体(G protein coupled receptors,GPCRs)超家族中的一员,也是研究治疗哮喘的关键药物受体靶标.采用进化踪迹(evolutionary trace,ET)方法分析肾上腺素受体家族跨膜区片段序...β2肾上腺素受体(β2adrenergic receptor,β2AR)是G蛋白耦联受体(G protein coupled receptors,GPCRs)超家族中的一员,也是研究治疗哮喘的关键药物受体靶标.采用进化踪迹(evolutionary trace,ET)方法分析肾上腺素受体家族跨膜区片段序列,识别出了44个保守的残基,然后将β2肾上腺素受体以及受体D130N活性突变体、D79N失活突变体进行分子动力学模拟,试图找出与受体不同功能状态相关的结构动力学特征.发现受体DRY motif中的D130远离R131而转向K149残基这一结构特征与受体活性高度关联,此外,从残基相互作用的变化推断出了受体helix 2,4 and 6伴随着受体活化而发生的运动.这些研究结果对进一步探索β2肾上腺素受体突变体的激活机制以及所诱发疾病的分子机理提供了依据.展开更多
A subgroup E of a finite group G is called hypercyclically embedded in G if every chief factor of G below E is cyclic.Let A be a subgroup of a group G.Then we call any chief factor H/AG of G a G-boundary factor of A.F...A subgroup E of a finite group G is called hypercyclically embedded in G if every chief factor of G below E is cyclic.Let A be a subgroup of a group G.Then we call any chief factor H/AG of G a G-boundary factor of A.For any G-boundary factor H/AG of A,we call the subgroup(A∩H)/AG of G/AG a G-trace of A.On the basis of these notions,we give some new characterizations of hypercyclically embedded subgroups.展开更多
Let G be a finite group, and let A be a proper subgroup of G. Then any chief factor H/AG of G is called a G-boundary factor of A. For any G- boundary factor H/AG of A, the subgroup （A ∩ H）/AG of G/AG is called a G-...Let G be a finite group, and let A be a proper subgroup of G. Then any chief factor H/AG of G is called a G-boundary factor of A. For any G- boundary factor H/AG of A, the subgroup （A ∩ H）/AG of G/AG is called a G-trace of A. In this paper, we prove that G is p-soluble if and only if every maximal chain of G of length 2 contains a proper subgroup M of G such that either some G-trace of M is subnormal or every G-boundary factor of M is a p′- group. This result give a positive answer to a recent open problem of Guo and Skiba. We also give some new characterizations of p-hypercyclically embedded subgroups.展开更多
文摘β2肾上腺素受体(β2adrenergic receptor,β2AR)是G蛋白耦联受体(G protein coupled receptors,GPCRs)超家族中的一员,也是研究治疗哮喘的关键药物受体靶标.采用进化踪迹(evolutionary trace,ET)方法分析肾上腺素受体家族跨膜区片段序列,识别出了44个保守的残基,然后将β2肾上腺素受体以及受体D130N活性突变体、D79N失活突变体进行分子动力学模拟,试图找出与受体不同功能状态相关的结构动力学特征.发现受体DRY motif中的D130远离R131而转向K149残基这一结构特征与受体活性高度关联,此外,从残基相互作用的变化推断出了受体helix 2,4 and 6伴随着受体活化而发生的运动.这些研究结果对进一步探索β2肾上腺素受体突变体的激活机制以及所诱发疾病的分子机理提供了依据.
基金Research of the first author is supported by aNNSFgrant ofChina(Grant#11371335)WuWen-Tsun Key Laboratory of Mathematics,USTC,Chinese Academy of Sciences.Research of the second author supported by Chinese Academy of Sciences Visiting Professorship for Senior International Scientists(Grant No.2010T2J12).
文摘A subgroup E of a finite group G is called hypercyclically embedded in G if every chief factor of G below E is cyclic.Let A be a subgroup of a group G.Then we call any chief factor H/AG of G a G-boundary factor of A.For any G-boundary factor H/AG of A,we call the subgroup(A∩H)/AG of G/AG a G-trace of A.On the basis of these notions,we give some new characterizations of hypercyclically embedded subgroups.
基金Acknowledgements The authors were grateful to the referees for their careful reading and helpful suggestions. This work was supported by the National Natural Science Foundation of China （Grant Nos. 11371335, 11471055） and Wu Wen-Tsun Key Laboratory of Mathematics of Chinese Academy of Sciences.
文摘Let G be a finite group, and let A be a proper subgroup of G. Then any chief factor H/AG of G is called a G-boundary factor of A. For any G- boundary factor H/AG of A, the subgroup （A ∩ H）/AG of G/AG is called a G-trace of A. In this paper, we prove that G is p-soluble if and only if every maximal chain of G of length 2 contains a proper subgroup M of G such that either some G-trace of M is subnormal or every G-boundary factor of M is a p′- group. This result give a positive answer to a recent open problem of Guo and Skiba. We also give some new characterizations of p-hypercyclically embedded subgroups.
