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951.
Artificial chromosome formation in maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) 总被引:1,自引:0,他引:1
Evgueni V. Ananiev Chengcang Wu Mark A. Chamberlin Sergei Svitashev Chris Schwartz William Gordon-Kamm Scott Tingey 《Chromosoma》2009,118(2):157-177
We report on the construction of maize minichromosomes using shuttle vectors harboring native centromeric segments, origins
of replication, selectable marker genes, and telomeric repeats. These vectors were introduced into scutellar cells of maize
immature embryos by microprojectile bombardment. Several independent transformation events were identified containing minichromosomes
in addition to the normal diploid complement of 20 maize chromosomes. Immunostaining indicated that the minichromosomes recruited
centromeric protein C, which is a specific component of the centromere/kinetochore complex. Minichromosomes were estimated
to be 15–30 Mb in size based on cytological measurements. Fluorescent in situ hybridization (FISH) showed that minichromosomes
contain the centromeric, telomeric, and exogenous unique marker sequences interspersed with maize retrotransposons. Minichromosomes
were detected for at least a year in actively dividing callus cultures, providing evidence for their stability through numerous
cell cycles. Plants were regenerated and minichromosomes were detected in root tips, providing confirmation of their normal
replication and transmission during mitosis and through organogenesis. Assembly of maize artificial chromosomes may provide
a tool to study centromere function and a foundation for developing new high capacity vectors for plant functional genomics
and breeding.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Evgueni V. Ananiev, deceased
Evgueni V. Ananiev and Chengcang Wu contributed equally to this work.
Novel materials described in this publication may be available for noncommercial research purposes on acceptance and signing
of a material transfer agreement. In some cases, such materials may contain or be derived from materials obtained from a third
party. In such cases, the distribution of material will be subject to the requisite permission from any third-party owners,
licensors, or controllers of all or parts of the material. Obtaining any permission will be the sole responsibility of the
requestor. 相似文献
952.
Guofeng Wu Jan de Leeuw Andrew K. Skidmore Herbert H. T. Prins Elly P. H. Best Yaolin Liu 《Hydrobiologia》2009,623(1):213-222
Almost 95% of the entire population of the Siberian crane (Grus leucogeranus) winter in Poyang Lake, China, where they forage on the tubers of the submerged aquatic macrophyte Vallisneria spiralis. The Three Gorges Dam on the Yangtze River may possibly affect this food source of the Siberian crane by affecting the light
intensity reaching the top of the V. spiralis canopy. In this study, the photosynthetically active radiation at the top of the V. spiralis canopy (PARtc) in Lake Dahuchi was modeled from 1998 to 2006, and the potential impacts of changes in water level and turbidity on the
underwater light climate of V. spiralis were analyzed. PARtc was calculated from incident irradiance while the losses due to reflection at the water surface, absorption, and scattering
within the water column were taken into consideration. The results indicated significant differences in PARtc between years. Six years of water level and Secchi disk depth records revealed a seasonal switching of the lake from a turbid
state at low water levels in autumn, winter, and spring to a clear state at high water levels during the monsoon in summer.
The highest PARtc occurred at intermediate water levels, which were reached when the Yangtze River forces Lake Dahuchi out of its turbid state
in early summer and the water becomes clear. The intended operation of the Three Gorges Dam, which will increase water levels
in May and June, may advance the moment when Lake Dahuchi switches from turbid to clear. We suggest that this might increase
production of V. spiralis and possibly improve the food habitat conditions for wintering Siberian crane in Poyang Lake.
相似文献
Guofeng WuEmail: |
953.
基于28S rDNA部分序列的石磺科系统发育研究 总被引:1,自引:0,他引:1
采用PCR技术对采集自中国大陆沿海5地8个群体石磺的28S rDNA部分序列进行扩增。将测序结果与Gen-Bank中的另外3条石磺科贝类的对应序列一起,以小鼠28S rDNA基因序列进行参照,截取D1、D2、D3区域,拼接后进行比对分析。在获得的689bp的序列中,有76个变异位点,28个简约信息位点,A+T平均含量为30.9%,C+G平均含量为69.0%。以分类关系较近的菊花螺科(Siphonaria alternate)为外群,用NJ、MP、ML和贝叶斯法构建分子系统树。4种方法得到的进化树拓扑结构很相似,得到的结果也与沈和定提出的中国大陆沿海石磺科贝类可划分为Peronia、Platevindex、Onchidium、Paraoncidium4个属的观点基本一致。同时,28S rDNA部分序列的系统分析还显示,4个属中Peronia属与Paraoncidium属亲缘关系较近,Platevindex属与Onchidium属关系比较近。 相似文献
954.
Microalgae have been a popular edible food, but there are no known reports on the antioxidative peptides derived from microalgae. The algae protein waste, which is normally discarded as animal feed, is a by-product during production of algae essence from microalgae, Chlorella vulgaris. Algae protein waste was hydrolyzed using pepsin, and a potent antioxidative peptide of VECYGPNRPQF was separated and isolated. The peptide could efficiently quench a variety of free radicals, including hydroxyl radical, superoxide radical, peroxyl radical, DPPH radical and ABTS radicals, and performed more efficiently than that observed for BHT, Trolox and peptides from marine protein sources in most cases. The purified peptide also has significant protective effects on DNA and prevents cellular damage caused by hydroxyl radicals. In addition, the peptide has gastrointestinal enzyme-resistance and no cytotoxicity observed in human lung fibroblasts cell lines (WI-38) in vitro. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce antioxidative peptides. 相似文献
955.
Antonella Pepe Liang Sun Ilaria Zanardi Xinyuan Wu Cristiano Ferlini Gabriele Fontana Ezio Bombardelli Iwao Ojima 《Bioorganic & medicinal chemistry letters》2009,19(12):3300-3304
Novel C-seco-taxoids were synthesized from 10-deacetylbaccatin III and their potencies evaluated against drug-sensitive and drug-resistant cancer cell lines. The drug-resistant cell lines include ovarian cancer cell lines resistant to cisplatin, topotecan, adriamycin and paclitaxel overexpressing class III β-tubulin, A2780TC1 and A2780TC3. The last two cell lines were selected through chronic exposure of A2780wt to paclitaxel and Pgp blocker cyclosporine. All novel C-seco-taxoids exhibited remarkable potency against A2780TC1 and A2780TC3 cell lines, and no cross resistance to cisplatin- and topotecan-resistant cell lines, A2780CIS and A2780TOP. Four of those C-seco-taxoids exhibit much higher activities than IDN5390 against paclitaxel-resistant cell lines, A2780ADR, A2780TC1 and A2780TC3. SB-CST-10202 possesses the best all-round high potencies across different drug-resistant cell lines. Molecular modeling studies, including molecular dynamics simulations, on the drug-protein complexes of class I and III β-tubulins were performed to identify possible cause of the remarkable potency of these C-seco-taxoids against paclitaxel-resistant cell lines overexpressing class III β-tubulin. 相似文献
956.
Marlys Hammond David G. Washburn Tram H. Hoang Sharada Manns James S. Frazee Hiroko Nakamura Jaclyn R. Patterson Walter Trizna Charlene Wu Leonard M. Azzarano Rakesh Nagilla Melanie Nord Rebecca Trejo Martha S. Head Baoguang Zhao Angela M. Smallwood Kendra Hightower Nicholas J. Laping Christine G. Schnackenberg Scott K. Thompson 《Bioorganic & medicinal chemistry letters》2009,19(15):4441-4445
The lead serum and glucocorticoid-related kinase 1 (SGK1) inhibitors 4-(5-phenyl-1H-pyrrolo[2,3-b]pyridin-3-yl)benzoic acid (1) and {4-[5-(2-naphthalenyl)-1H-pyrrolo[2,3-b]pyridin-3-yl]phenyl}acetic acid (2) suffer from low DNAUC values in rat, due in part to formation and excretion of glucuronic acid conjugates. These PK/glucuronidation issues were addressed either by incorporating a substituent on the 3-phenyl ring ortho to the key carboxylate functionality of 1 or by substituting on the group in between the carboxylate and phenyl ring of 2. Three of these analogs have been identified as having good SGK1 inhibition potency and have DNAUC values suitable for in vivo testing. 相似文献
957.
Iou-Jiun Kang Li-Wen Wang Sheng-Ju Hsu Chung-Chi Lee Yen-Chun Lee Yen-Shian Wu Andrew Yueh Jing-Chyi Wang Tsu-An Hsu Yu-Sheng Chao Jyh-Haur Chern 《Bioorganic & medicinal chemistry letters》2009,19(21):6063-6068
A novel class of arylthiourea HCV inhibitors bearing various functionalities, such as cyclic urea, cyclic thiourea, urea, and thiourea, on the alkyl linker were designed and synthesized. Herein we report the synthesis and structure–activity relationships (SARs) of this novel class of arylthiourea derivatives that showed potent inhibitory activities against HCV in the cell-based subgenomic HCV replicon assay. Among compounds tested, the new carbazole derivative 64, which has an eight-carbon linkage between the phenyl and carbazole rings and a tolyl group at the N-9 position of carbazole, was found to possess strong anti-HCV activity (EC50 = 0.031 μM), lower cytotoxicity (CC50 >50 μM), and higher selectivity index (SI >1612) compared to its derivatives. 相似文献
958.
在提供"生物微核技术监测水质的污染"研究性学习案例的基础上,通过展现该研究性学习的过程,介绍了该案例的设计、实践操作过程与实践成果,并对该研究性学习的实施过程进行了教学反思。 相似文献
959.
目的:探讨应激对机体脑体功能的损伤效应及其生物学机制,为应激损伤防护措施的制订提供科学依据。方法:采用束缚应激模型,观察模型动物认知功能、体能、海马LTP、血浆糖皮质激素、心电图、心肌组织结构等指标的变化。结果:应激动物学习记忆能力和运动耐力明显下降,血浆糖皮质激素水平显著升高,海马LTP诱发受到抑制,心电图异常改变,心功能紊乱,心肌组织结构出现病理损伤,心肌细胞凋亡率增加,心肌组织Hsp70表达水平随应激强度增加而逐渐降低。结论:应激诱导机体神经一内分泌功能紊乱,进而导致机体脑体功能损伤。 相似文献
960.
Weifeng Wang Jia Guo Dongyang Yu Paul J. Vorster WanJun Chen Yuntao Wu 《The Journal of biological chemistry》2012,287(42):35455-35469
Human memory and naive CD4 T cells can mainly be identified by the reciprocal expression of the CD45RO or CD45RA isoforms. In HIV-1 infection, blood CD45RO memory CD4 T cells are preferentially infected and serve as a major viral reservoir. The molecular mechanism dictating this differential susceptibility to HIV-1 remains largely obscure. Here, we report that the different susceptibility of memory and naive T cells to HIV is not determined by restriction factors such as Apobec3G or BST2. However, we observed a phenotypic distinction between human CD45RO and CD45RA resting CD4 T cells in their cortical actin density and actin dynamics. CD45RO CD4 T cells possess a higher cortical actin density and can be distinguished as CD45RO+Actinhigh. In contrast, CD45RA T cells are phenotypically CD45RA+Actinlow. In addition, the cortical actin in CD45RO memory CD4 T cells is more dynamic and can respond to low dosages of chemotactic induction by SDF-1, whereas that of naive cells cannot, despite a similar level of the chemokine receptor CXCR4 present on both cells. We further demonstrate that this difference in the cortical actin contributes to their differential susceptibility to HIV-1; resting memory but not naive T cells are highly responsive to HIV-mediated actin dynamics that promote higher levels of viral entry and early DNA synthesis in resting memory CD4 T cells. Furthermore, transient induction of actin dynamics in resting naive T cells rescues HIV latent infection following CD3/CD28 stimulation. These results suggest a key role of chemotactic actin activity in facilitating HIV-1 latent infection of these T cell subsets. 相似文献