| 1. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 2. |
- Hua, Dong, et al.
(författare)
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Small interfering RNA-directed targeting of toll-like receptor 4 inhibits human prostate cancer cell invasion, survival, and tumorigenicity
- 2009
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Ingår i: Molecular Immunology. - : Elsevier BV. - 0161-5890 .- 1872-9142. ; 46:15, s. 2876-2884
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Tidskriftsartikel (refereegranskat)abstract
- A major cause of tumor treatment failure is cancer cell metastasis. Toll-like receptor 4 (TLR4)-mediated signaling has been implicated in tumor cell invasion, survival, and metastasis in a variety of cancers. In this study, we investigated the biological roles of TLR4 in prostate metastatic cell invasion and survival, and the potential of gene silencing of TLR4 using small interfering RNA (siRNA) for treatment of cancer. In cultured human prostate cancer cell lines, TLR4 were higher PC3 and DU145 as compared with the poorly metastatic LNCaP indicating that up-regulation of TLR4 was positively correlated with metastasis of tumor cell. In the highly metastatic cancer cell PC3, gene silencing of TLR4 using siRNA significantly inhibited TLR4 mRNA expression and protein level. Knockdown of TLR4 in PC3 cells resulted in a dramatic reduction of tumor cell migration and invasion as indicated by a Matrigel invasion assay. Furthermore, TLR4 siRNA suppressed cell viability and ultimately caused the induction of apoptotic cell death. The effects were associated with abrogating TLR4-mediated signaling to downstream target molecules such as myeloid differentiation factor 88 (MyD88), adaptor-inducing IFN-beta (TRIF), and interferon regulatory factor-1 (IRF-1). In a mouse prostate cancer model, administration with the plasmid construct expressing siRNA for TLR4 obviously inhibited established tumor growth and survival. These studies revealed evidence of a multifaceted signaling network operating downstream of TLR4-mediated tumor cell invasion, proliferation, and survival. Thus, RNA interference-directed targeting of TLR4 may raise the potential of its application for cancer therapy.
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| 3. |
- Li, Zhenyu, et al.
(författare)
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How Graphene is Cut upon Oxidation?
- 2009
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 131:18, s. 6320-6321
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Tidskriftsartikel (refereegranskat)abstract
- Our first principles calculations reveal that an oxidative cut of graphene is realized by forming epoxy and then carbonyl pairs. Direct formation of a carbonyl pair to tear graphene up from an edge position is not favorable in energy. This atomic picture is valuable for developing effective means of graphene manipulation. The proposed epoxy pairs may be related to some long puzzling experimental observations on graphene oxide.
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| 4. |
- Richards, Stephen, et al.
(författare)
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The genome of the model beetle and pest Tribolium castaneum.
- 2008
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Ingår i: Nature. - 1476-4687. ; 452:7190, s. 949-55
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Tidskriftsartikel (refereegranskat)abstract
- Tribolium castaneum is a representative of earth’s most numerous eukaryotic order, a powerful model organism for the study of generalized insect development, and also an important pest of stored agricultural products. We describe its genome sequence here. This omnivorous beetle has evolved an ability to interact with a diverse chemical environment as evidenced by large expansions in odorant and gustatory receptors, as well as p450 and other detoxification enzymes. Developmental patterns in Tribolium are more representative of other arthropods than those found in Drosophila, a fact represented in gene content and function. For one, Tribolium has retained more ancestral genes involved in cell-cell communication than Drosophila, and some are expressed in the growth zone crucial for axial elongation in short germ development. Systemic RNAi in T. castaneum appears to use mechanisms distinct from those found in C. elegans, but nevertheless offers similar power for the elucidation of gene function and identification of targets for selective insect control.
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| 5. |
- Tian, Jian-jun, et al.
(författare)
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Influence of heat treatment on fracture and magnetic properties of radially oriented Sm 2 Co 17 permanent magnets
- 2007
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Ingår i: Transactions of Nonferrous Metals Society of China. - 1003-6326 .- 2210-3384. ; 17:3, s. 491-495
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Tidskriftsartikel (refereegranskat)abstract
- The quenching, fracture and aging treatment of radially oriented Sm2Co17 ring magnets were investigated. The results indicate that the ring magnets have obvious anisotropy of thermal expansion, which easily leads to the splits of the magnets during quenching. The fracture is brittle cleavage fracture. The difference (δa) of the expansion coefficient reaches the maximum value at 800–850 °C. So, various quenching processes at different steps are adopted in order to reduce the splits. When the magnets are aged. 1:5 phase precipitates from the 2:17 matrix phase and forms a cellular microstructure with 2:17 phase. BHmax and 3Hc reach the maximum value 226 kJ/m3 and 2170 kA/m after being aged at 850 °C for 4 h and 8 h, respectively. The aging treatment at 850 °C has little influence on remanence(Br), which can always keep a high value (≥1.0 T). Through appropriate heat treatment, the ring magnets have uniform cellular microstructure and excellent magnetic properties: Br1.0T, 3Hc≥2 100 kA/m, BHmax≥220 kJ/m3.
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| 6. |
- Zhang, Wei, et al.
(författare)
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Synthesis and characterization of some new mononuclear ruthenium complexes containing 4-(un) substituted dipyridylpyrazole ligands
- 2008
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Ingår i: Polyhedron. - : Elsevier BV. - 0277-5387 .- 1873-3719. ; 27:4, s. 1168-1176
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Tidskriftsartikel (refereegranskat)abstract
- A mononuclear ruthenium complex [Ru(bpy)(2)(bpp)](PF6) (1) and its halogenated and nitro derivatives [Ru(bpy)(2)(Xbpp)](PF6) (bpy = 2,2'-bipyridine; bpp = 3,5-bis(2-pyridyl)pyrazole; X = Cl, 2; X = Br, 3; X = I, 4; X = NO2, 5) have been synthesized and characterized by H-1 NMR, C-13 NMR, HRMS, elemental analysis. Complexes 2-5 have been further confirmed by X-ray diffraction. Their UV-Vis and emission spectroscopies, electrochemical measurements and acid-base properties are described. The results presented here reveal that the introduction of Cl, Br, I and NO2 groups to the coordinated bpp(-) ligand makes the absorption and emission maxima of the parent complex 1 blue-shifted, the oxidation potential of the Ru-II/Ru-III couple increased and the pK(a) value decreased obviously. In addition, significant quenching of the emission by these groups is also observed.
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| 7. |
- Zhang, Zhifei, et al.
(författare)
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Architecture and function of the lophophore in the problematic brachiopod Heliomedusa orienta (Early Cambrian, South China)
- 2009
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Ingår i: Geobios. - : Elsevier BV. - 0016-6995 .- 1777-5728. ; 42:5, s. 649-661
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Tidskriftsartikel (refereegranskat)abstract
- The detailed structure of the lophophore is a key diagnostic character in the definition of higher brachiopod taxa. The problematic Heliomedusa orienta Sun and Hou, from the Lower Cambrian Chengjiang Lagerstatte of Yunnan, southwestern China, has a well-preserved lophophore, which is unlike that of any known extant or extinct brachiopods. Based on a comparative study of lophophore disposition in H. orienta and the extant discinid Pelagodiscus atlanticus, the in- and excurrent pattern and shell orientation of H. orienta are described and discussed. Reconstructions of lophophore shape and function are based on numerous specimens and comparison with P. atlanticus. The lophophore is composed of a pair of lophophoral arms that freely arch posteriorly rather than coiling anteriorly as commonly seen in fossil and recent lingulids. The lophophore is attached to the dorsal lobe of the mantle; it has neither calcareous nor chitinous supporting structures, and is disposed symmetrically on either side of the valve midline. The mouth can be inferred to be located at the base of the two brachial tubes, slightly posterior to the anterodorsal projection of the body wall. The lophophoral arms bear laterofrontal tentacles with a double row of cilia along their lateral edge, as in extant lingulid brachiopods. The main brachial axes are also ciliated, which presumably facilitated transport of mucous-bound nutrient particles to the mouth. The unique organization of the lophophore in Heliomedusa is not like any known fossil and living brachiopods. This clearly demonstrates that H. orienta is not a member of any crown group. It is here considered as a member of the brachiopod stem group, which challenges recent interpretations of a close discinid affinity. (C) 2009 Elsevier Masson SAS. All rights reserved.
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