| 1. |
- Duan, Ming-Rui, et al.
(författare)
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DNA binding mechanism revealed by high resolution crystal structure of Arabidopsis thaliana WRKY1 protein
- 2007
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 35:4, s. 54-1145
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Tidskriftsartikel (refereegranskat)abstract
- WRKY proteins, defined by the conserved WRKYGQK sequence, are comprised of a large superfamily of transcription factors identified specifically from the plant kingdom. This superfamily plays important roles in plant disease resistance, abiotic stress, senescence as well as in some developmental processes. In this study, the Arabidopsis WRKY1 was shown to be involved in the salicylic acid signaling pathway and partially dependent on NPR1; a C-terminal domain of WRKY1, AtWRKY1-C, was constructed for structural studies. Previous investigations showed that DNA binding of the WRKY proteins was localized at the WRKY domains and these domains may define novel zinc-binding motifs. The crystal structure of the AtWRKY1-C determined at 1.6 A resolution has revealed that this domain is composed of a globular structure with five beta strands, forming an antiparallel beta-sheet. A novel zinc-binding site is situated at one end of the beta-sheet, between strands beta4 and beta5. Based on this high-resolution crystal structure and site-directed mutagenesis, we have defined and confirmed that the DNA-binding residues of AtWRKY1-C are located at beta2 and beta3 strands. These results provided us with structural information to understand the mechanism of transcriptional control and signal transduction events of the WRKY proteins.
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| 2. |
- Huang, Daming, et al.
(författare)
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A Modified Charge-Pumping Method for the Characterization of Interface-Trap Generation in MOSFETs
- 2009
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Ingår i: IEEE Transactions on Electron Devices. - 0018-9383 .- 1557-9646. ; 56:2, s. 267-274
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Tidskriftsartikel (refereegranskat)abstract
- A novel recovery-free interface-trap measurement method is presented in detail. This method is the modification of the conventional charge pumping (CP) by extending the pulse low level to the stress-bias and minimizing the pulse high-level duty cycle to suppress the recovery effect. The method is applied to study the negative-bias temperature instability in p-MOSFETs. As compared with the conventional CP, a much larger interface-trap generation under stress is observed by the new method. A power law time dependence (similar to t(n)) of interface-trap generation is observed. The index n. is less than that derived from conventional CP and increases with temperature, demonstrating a dispersive process involved in the trap generation dynamics.
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| 3. |
- Li, Xuemei, et al.
(författare)
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Perfluorooctanesulfonate and related fluorochemicals in the Amur tiger (Panthera tigris altaica) from China
- 2008
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 42:19, s. 7078-7083
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Tidskriftsartikel (refereegranskat)abstract
- Perfluorinated compounds (PFCs) are used in a variety of industrial applications. We tested the hypothesis that, in Amur tigers (Panthera tigris altaica), captivity in industrialized areas increases PFC levels, potentially presenting a health risk to these animals. Serum samples were collected from 100 tigers from industrialized or nonindustrialized regions in China with nonpoint sources of PFCs. Mean concentrations of PFCs in these samples ranged from 1.57 ± 0.83 ng/mL in nonindustrial Hailin to 4.31 ± 2.90 ng/mL in industrial Beijing. PFC concentrations were significantly higher in tigers from the industrial city of Harbin than those from Hailin (p < 0.05). Perfluorooctanesulfonate (PFOS) was the most abundant PFC in all tigers and increased with age, regardless of industrial/nonindustrial background (p < 0.01). However, PFOS concentrations were 2-4 orders of magnitude less than the current no-observed-effect level. In addition, overall PFC levels in Amur tigers were low compared with various species living in other countries, consistent with the relatively short history of PFC use in China. These results are consistent with the hypothesis that captivity in industrialized areas increases PFC levels in Amurtigers. They also suggestthat PFC accumulation will persist, and even increase, with continued use of PFCs in China.
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| 4. |
- Li, Xin, et al.
(författare)
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Study on enhancement of fluorescence with gold nanorods
- 2008
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Ingår i: Asia Optical Fiber Communication and Optoelectronic Exposition and Conference 2008. - : Optical Society of America. - 9781557528636
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Konferensbidrag (refereegranskat)abstract
- Enhancement of fluorescence of streptavidin conjugated with gold nanorods (GNRs) was observed. The impact of GNRs with different surface plasmon resonance bands and different concentrations to the efficiency of the fluorescence enhancement was studied.
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| 5. |
- Zhang, Zhi-Yong, et al.
(författare)
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Nup88 expression in normal mucosa, adenoma, primary adenocarcinoma and lymph node metastasis in the colorectum
- 2007
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Ingår i: Tumor Biology. - : Springer Science and Business Media LLC. - 1010-4283 .- 1423-0380. ; 28:2, s. 93-99
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: It was the aim of this study to investigate Nup88 expression in normal colorectal mucosa, adenoma, adenocarcinoma and lymph node metastasis, as well as the relationship between Nup88 expression and clinicopathological features. Methods: Nup88 expression was examined by immunohistochemistry in 84 normal mucosa samples, 32 adenomas, 181 primary adenocarcinomas, and 18 lymph node metastases from colorectal tumour patients. Results: Nup88 expression was observed in normal epithelial and tumour cells. The frequency of strong Nup88 expression was increased from normal mucosa or adenoma to primary tumour and lymph node metastasis (p < 0.0001). There was no significant difference in the expression between normal mucosa and adenoma (p = 0.41). The frequency of strong Nup88 expression was higher in ulcerated tumours (40%) than in polypoid/large fungating tumours (23%, p = 0.048). The frequency of strong Nup88 expression was significantly different among tumours with good (21%), moderate (42%) and poor differentiation (48%, p = 0.01). Nup88 expression was not related to the patients' gender, age, tumour location, size, histological type, invasive depth, lymph node status and Dukes stage (p > 0.05). Conclusion: Our results suggest that Nup88 may play a role during the development, aggressiveness and differentiation of colorectal tumours. Copyright © 2007 S. Karger AG.
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| 6. |
- Ambring, Anneli, 1964, et al.
(författare)
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Mediterranean-inspired diet lowers the ratio of serum phospholipid n-6 to n-3 fatty acids, the number of leukocytes and platelets, and vascular endothelial growth factor in healthy subjects.
- 2006
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Ingår i: The American journal of clinical nutrition. - 0002-9165. ; 83:3, s. 575-81
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Reduced cardiovascular mortality and morbidity have been shown in persons adhering to Mediterranean-inspired diets (MIDs). Although the underlying mechanisms of this association are poorly understood, the importance of increasing dietary amounts of polyunsaturated fatty acids of the n-3 series has been emphasized. OBJECTIVE: We investigated whether a MID provided to healthy subjects would affect 1) the inflammatory process and endothelial indexes such as vasoregulation and vascular endothelial growth factor (VEGF) and 2) serum phospholipid fatty acid composition. DESIGN: A total of 22 subjects (10 women) received a MID or an ordinary Swedish diet (OSD) for 4 wk in a crossover fashion. Concentrations of lipids and fatty acids, high-sensitivity C-reactive protein, and interleukin 6, both before and after lipopolysaccharide stimulation; the number of leukocytes and platelets; and VEGF and monocyte chemoattractant protein 1 were analyzed. RESULTS: The plasma ratio of n-6 to n-3 fatty acids was substantially lower after the MID than after the OSD (x +/- SEM: 4.72 +/- 0.19 and 2.60 +/- 0.17, respectively; P < 0.0001). Neither C-reactive protein nor interleukin 6 concentrations changed significantly after the MID compared with the OSD. The total number of leukocytes and platelets was 10% (P < 0.05) and 15% (P < 0.001) lower, respectively, after the MID than after the OSD. Serum VEGF concentrations were lower after the MID than after the OSD (237 +/- 30 and 206 +/- 25 pg/mL, respectively; P = 0.0014). CONCLUSIONS: A MID reduces the number of platelets and leukocytes and VEGF concentrations in healthy subjects. This may be linked to higher serum concentrations of n-3 fatty acids, which promote a favorable composition of phospholipids.
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| 7. |
- Andersson, Irene, 1978, et al.
(författare)
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Endothelial dysfunction in growth hormone transgenic mice
- 2006
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Ingår i: Clinical Science. - 0143-5221 .- 1470-8736. ; 110:2, s. 217-25
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Tidskriftsartikel (refereegranskat)abstract
- Acromegaly [overproduction of GH (growth hormone)] is associated with cardiovascular disease. Transgenic mice overexpressing bGH (bovine GH) develop hypertension and hypercholesterolaemia and could be a model for cardiovascular disease in acromegaly. The aims of the present study were to investigate the effects of excess GH on vascular function and to test whether oxidative stress affects endothelial function in bGH transgenic mice. We studied the ACh (acetylcholine)-induced relaxation response in aortic and carotid rings of young (9-11 weeks) and aged (22-24 weeks) female bGH transgenic mice and littermate control mice, without and with the addition of a free radical scavenger {MnTBAP [Mn(III)tetrakis(4-benzoic acid)porphyrin chloride]}. We also measured mRNA levels of eNOS (endothelial nitric oxide synthase) and EC-SOD (extracellular superoxide dismutase). Intracellular superoxide anion production in the vascular wall was estimated using a dihydroethidium probe. Carotid arteries from bGH transgenic mice had an impaired ACh-induced relaxation response (young, 46 +/- 7% compared with 69 +/- 8%; aged, 52 +/- 5% compared with 80 +/- 3%; P < 0.05), whereas endothelial function in aorta was intact in young but impaired in aged bGH transgenic mice. Endothelial dysfunction was corrected by addition of MnTBAP in carotid arteries from young mice and in aortas from aged mice; however, MnTBAP did not correct endothelial dysfunction in carotid arteries from aged bGH transgenic mice. There was no difference in intracellular superoxide anion production between bGH transgenic mice and control mice, whereas mRNA expression of EC-SOD and eNOS was increased in aortas from young bGH transgenic mice compared with control mice (P < 0.05). We interpret these data to suggest that bGH overexpression is associated with a time- and vessel-specific deterioration in endothelial function, initially caused by increased oxidative stress and later by other alterations in vascular function.
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| 8. |
- Andersson, Irene, 1978, et al.
(författare)
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Increased atherosclerotic lesion area in apoE deficient mice overexpressing bovine growth hormone
- 2006
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Ingår i: Atherosclerosis. - : Elsevier BV. - 0021-9150. ; 188:2, s. 331-40
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Tidskriftsartikel (refereegranskat)abstract
- Human growth hormone (GH) excess is linked to increased cardiovascular morbidity and mortality. However, little is known about the effect of GH excess on atherosclerosis. We developed a new mouse model to assess the hypothesis that GH overexpression accelerates atherosclerotic lesion formation. apoE(-/-) mice were crossed with bovine GH (bGH) transgenic mice to yield apoE(-/-) mice overexpressing bGH (apoE(-/-)/bGH). The mice were fed either standard or Western diet. At 22 weeks, atherosclerotic lesion area of thoracic aorta was larger in apoE(-/-)/bGH mice compared with littermate apoE(-/-) mice fed either diet (standard: +161+/-50%, Western: +430+/-134%). Aortic sinus lesions were more severe in apoE(-/-)/bGH mice fed standard diet compared with littermate apoE(-/-) mice. apoE(-/-)/bGH mice had lower (VLDL+LDL)/HDL ratios compared with littermate apoE(-/-) mice, while systolic blood pressure was higher in apoE(-/-)/bGH mice, irrespective of diet. The levels of serum amyloid A and hepatic CRP mRNA were higher in apoE(-/-)/bGH mice than in littermate apoE(-/-) mice. In conclusion, this study shows that excess GH augments the development of atherosclerosis in apoE(-/-) mice. The mechanisms could be direct effects of GH on cellular processes in the vessel wall or the result of concomitant processes such as hypertension or a general inflammatory state.
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| 9. |
- Bernberg, Evelina, 1981, et al.
(författare)
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Effects of social isolation and environmental enrichment on atherosclerosis in ApoE-/- mice
- 2008
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Ingår i: Stress. - 1607-8888 .- 1025-3890. ; 11:5, s. 381-9
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Tidskriftsartikel (refereegranskat)abstract
- Social support and a stimulating environment have been suggested to reduce stress reactions and cardiovascular risk. The aim of this study was to assess the role of environmental enrichment and social interaction for development of atherosclerosis in atherosclerosis prone mice. Male ApoE-/- mice were divided into four groups and followed during 20 weeks: (i) enriched environment (E, n=12), (ii) deprived environment (ED, n=12), (iii) enriched environment with exercise (E-Ex, n=12) and (iv) socially deprived by individual housing (SD, n=10). Plasma lipid and cytokine concentrations were measured. Atherosclerosis was quantified in cross-sections of innominate artery and en face in thoracic aorta. Plaque area was significantly increased in SD mice in the innominate artery (P<0.05 vs. all other groups), but not in the thoracic aorta. Plasma lipids were increased in SD mice (P<0.001 vs. all for total cholesterol, P<0.05 vs. E and P<0.01 vs. ED for triglycerides). Plasma concentration of granulocyte-colony stimulating factor (G-CSF) was decreased in SD mice compared to E mice (P<0.05). Thus, social isolation increased atherosclerosis and plasma lipids in ApoE-/- mice. Reduction in plasma G-CSF levels may hamper endothelial regeneration in the atherosclerotic process. While environmental enrichment did not affect atherosclerosis, social isolation accelerated atherosclerosis.
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| 10. |
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