| 1. |
- Du, Qian, et al.
(författare)
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Porcine circovirus type 2 infection promotes the SUMOylation of nucleophosmin-1 to facilitate the viral circular single-stranded DNA replication
- 2024
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 20:2
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Tidskriftsartikel (refereegranskat)abstract
- The mechanism of genome DNA replication in circular single-stranded DNA viruses is currently a mystery, except for the fact that it undergoes rolling-circle replication. Herein, we identified SUMOylated porcine nucleophosmin-1 (pNPM1), which is previously reported to be an interacting protein of the viral capsid protein, as a key regulator that promotes the genome DNA replication of porcine single-stranded DNA circovirus. Upon porcine circovirus type 2 (PCV2) infection, SUMO2/3 were recruited and conjugated with the K263 site of pNPM1's C-terminal domain to SUMOylate pNPM1, subsequently, the SUMOylated pNPM1 were translocated in nucleoli to promote the replication of PCV2 genome DNA. The mutation of the K263 site reduced the SUMOylation levels of pNPM1 and the nucleolar localization of pNPM1, resulting in a decrease in the level of PCV2 DNA replication. Meanwhile, the mutation of the K263 site prevented the interaction of pNPM1 with PCV2 DNA, but not the interaction of pNPM1 with PCV2 Cap. Mechanistically, PCV2 infection increased the expression levels of Ubc9, the only E2 enzyme involved in SUMOylation, through the Cap-mediated activation of ERK signaling. The upregulation of Ubc9 promoted the interaction between pNPM1 and TRIM24, a potential E3 ligase for SUMOylation, thereby facilitating the SUMOylation of pNPM1. The inhibition of ERK activation could significantly reduce the SUMOylation levels and the nucleolar localization of pNPM1, as well as the PCV2 DNA replication levels. These results provide new insights into the mechanism of circular single-stranded DNA virus replication and highlight NPM1 as a potential target for inhibiting PCV2 replication. Different types of DNA viruses employ different mechanisms to replicate their genome DNA. Porcine circovirus type 2 (PCV2) is the most representative circular single-stranded DNA virus that harms the pig industry all over the world. In this study, we found that the PCV2 Cap interacting protein pNPM1 also interacts with PCV2 DNA in a SUMOylated form to promote PCV2 DNA replication. The SUMOylation of pNPM1 at the conserved K263 site is critical for the interaction of pNPM1 with PCV2 DNA and the replication of PCV2 DNA. Furthermore, we found that PCV2 infection promotes the SUMO2/3 mediated SUMOylation of pNPM1, while does not significantly alter the expression level of pNPM1. PCV2 Cap is the major component that promotes pNPM1 SUMOylation by activating ERK/Ubc9/TRIM24 signalings. These results contribute to a better understanding of the replication mechanism of circular single-stranded DNA viruses, particularly PCV2.
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| 2. |
- Liu, Xiang, et al.
(författare)
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N-Acetyl peak in MR spectra of intracranial metastatic mucinous adenocarcinomas.
- 2010
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Ingår i: Magnetic resonance imaging. - : Elsevier BV. - 1873-5894 .- 0730-725X. ; 28:9, s. 1390-4
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Tidskriftsartikel (refereegranskat)abstract
- Absence of N-acetylaspartate (NAA) is one important diagnostic criterion of MR spectroscopy (MRS) that may suggest that an intracranial mass lesion is a metastasis. We report two cases of histopathology-confirmed intracranial metastatic mucinous adenocarcinoma, which predominantly showed a large metabolite peak at 2.0 ppm, mimicking an NAA peak of normal brain tissue. This finding could be of help in the interpretation of MRS in cases of intracranial enhancing mass lesions, metastases or gliomas.
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| 3. |
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| 4. |
- Niu, Guoxiang, et al.
(författare)
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Effects of nitrogen and water addition on soil carbon, nitrogen, phosphorus, sulfur, and their stoichiometry along soil profile in a semi-arid steppe
- 2023
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Ingår i: Journal of Soils and Sediments. - 1439-0108. ; 23:9, s. 3298-3309
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Although past studies have found well-constrained soil carbon (C)/nutrient ratios, the effects of increased nitrogen (N) and water inputs on these ratios across soil depths have rarely been assessed in semi-arid grasslands. Methods: In this study, we evaluated the contents of total C, N, phosphorus (P), sulfur (S), and their stoichiometric ratios in a 0–80 cm soil profile following 13 years of successive N (at rates of 5 and 15 g m−2 yearr−1) and water addition (180 mm per growing season) in a semi-arid grassland of the Mongolian Plateau. Results: In the 0–10 cm soil layer, long-term N addition tended to increase total C and N contents but decreased soil total P and S contents compared to the control. The effects of N addition, as observed in 0–10 cm soil, however, were not consistent with that in the deep 10–80 cm soil layers. Water addition increased the total C, N, and P contents across the entire soil profile but increased total S content only in 0–40 cm soil. Moreover, the combined addition of N and water generally had stronger effects on the four elements across the whole soil profile. For the stoichiometry of the four elements, a low rate of N addition (5 g m−2 year−1) increased soil C:N ratios and decreased soil P:S ratios in the 0–80 cm soils, but a high rate of N addition (15 g m−2 year−1) produced the opposite effect. Both N addition rates resulted in an increase in the soil C:P, C:S, N:P, and N:S ratios. Similarly, in plots that received water, water addition alone decreased the soil C:N ratios, while N addition caused higher fluctuations in these six elemental ratios. However, there was no consistent pattern of change in any one ratio, independent of the addition of water, when taking into account N addition rates and soil depths. Conclusion: Our findings showed that the effects of N addition on soil total C, N, P, and S contents and their stoichiometric ratios were highly influenced by the rate of N addition and the depth of soil, and that these effects could be modulated by increasing precipitation. These results need to be carefully considered while managing the ecological environment in semi-arid steppes.
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| 5. |
- Sundal, Christina, et al.
(författare)
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Different Stages of White Matter Changes in the Original HDLS Family Revealed by Advanced MRI Techniques.
- 2014
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Ingår i: Journal of neuroimaging : official journal of the American Society of Neuroimaging. - : Wiley. - 1552-6569. ; 24:5, s. 444-452
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The temporal evolution of white matter (WM) changes on MR examinations in hereditary diffuse leukoencephalopathy with spheroids (HDLS) is largely unknown. Our purpose was to investigate the evolution of these WM changes with diffusion weighted/tensor imaging (DWI/DTI) and MR Spectroscopy (MRS). METHODS: A newly diagnosed patient with HDLS from the original Swedish family was followed prospectively with 5 MRI as well as DWI/DTI and MRS examinations during 16 months. RESULTS: The DTI eigenvalues demonstrated changes that suggested early myelin and axonal disturbances in the normal appearing WM (NAWM). DWI/DTI showed a rim of decreased diffusion progressively expanding through the WM from the initial frontal periventricular zones, and indicated complete destruction of axons and myelin in the area behind the front. MRS findings were suggestive of axonal destruction in the NAWM. CONCLUSION: We describe HDLS changes in three temporal stages of development corresponding to lesions outside, in the vicinity of, and behind a characteristic rim centrifugally progressing from the ventricular horns. The axonal disturbances indicated by MRS changes in the NAWM support a primary axonal degeneration, as proposed in the original HDLS report, rather than axonal degeneration secondary to demyelination. These findings could help in differential diagnosis of HDLS.
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| 6. |
- Wang, Zhongwei, et al.
(författare)
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Design of performance-based frequency regulation market and its implementations in real-time operation
- 2017
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Ingår i: International Journal of Electrical Power & Energy Systems. - : Elsevier. - 0142-0615 .- 1879-3517. ; 87, s. 187-197
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Tidskriftsartikel (refereegranskat)abstract
- The importance of the performance of frequency regulation has already been acknowledged by regulators and Independent System Operators (ISOs). A performance-based frequency regulation market model considering both regulation capacity and regulation mileage constraints is proposed in this paper. In the proposed market, high-performance regulation resources have higher priorities to be selected in the market. Market clearing prices are derived with Lagrange relaxation. The analysis of the components of market clearing prices accurately indicates the correlation between regulation capacity and regulation mileage. To accommodate the proposed regulation market design, AGC allocation algorithm is adjusted based on the market clearing results. The clearing procedure of the market model is demonstrated on an illustrative case. The proposed market design is tested and verified with market simulations and system dynamic simulations. Simulation results are discussed and compared to show the effectiveness of the proposed market design.
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