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| 2. |
- Qu, Chang, et al.
(författare)
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Functional significance of asymmetrical retention of parental alleles in a hybrid pine species complex
- 2024
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Ingår i: Journal of Systematics and Evolution. - : John Wiley & Sons. - 1674-4918 .- 1759-6831. ; 62:1, s. 135-148
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid genomes usually harbor asymmetrical parental contributions. However, it is challenging to infer the functional significance of asymmetrical retention of parental alleles in hybrid populations of conifer trees. Here we investigated the diversity in the glutathione S-transferase (GST) gene family in a hybrid pine Pinus densata and its parents (Pinus tabuliformis and Pinus yunnanensis). Plant GSTs play major roles in protecting plants against biotic and abiotic stresses. In this study, 19 orthologous groups of GST genes were identified and cloned from these three species. We examined their expression in different tissues, and then purified the corresponding proteins to characterize their enzymatic activities and specificities toward different substrates. We found that among the 19 GST orthologous groups, divergence in gene expression and in enzymatic activities toward different substrates was prevalent. P. densata preferentially retained P. yunnanensis-like GSTs for 17 out of the 19 gene loci. We determined the first GST crystal structure from conifer species at a resolution of 2.19 Å. Based on this structure, we performed site-directed mutagenesis to replace amino acid residuals in different wild-types of GSTs to understand their functional impacts. Reciprocal replacement of amino acid residuals in native GSTs of P. densata and P. tabuliformis demonstrated significant changes in enzyme functions and identified key sites controlling GSTs activities. This study illustrates an approach to evaluating the functional significance of sequence variations in conifer genomes. Our study also sheds light on plausible mechanisms for controlling the selective retention of parental alleles in the P. densata genome.
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| 3. |
- Ding, Zhen-Yu, et al.
(författare)
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Upregulation of the antiapoptotic factor Livin contributes to cisplatin resistance in colon cancer cells
- 2013
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Ingår i: Tumor Biology. - : Karger / Springer Verlag (Germany). - 1010-4283 .- 1423-0380. ; 34:2, s. 683-693
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Tidskriftsartikel (refereegranskat)abstract
- The antiapoptotic factor Livin has been considered critical for tumor progression and poor prognosis for variant types of tumors. However, there are only limited reports regarding its expression and biological functions in colon cancer. Here, we examined Livin expression in four colon cancer cell lines (HCT116, RKO, KM12C, and SW620) in the presence or absence of cisplatin that was used as a model reagent. We found the different response to cisplatin was related to endogenous Livin expression level. From among a panel of apoptosis-related factors (p53, Bcl-2, Bcl-XL, BAX, and survivin), the expression of Livin was upregulated after cisplatin treatment in a dose-dependent manner. Both immunocytochemistry and nuclear cytoplasmic fractionation indicated Livin remained in the cytoplasm after treatment with cisplatin. In an attempt to explore the mechanism, we found the elevated expression of Livin was not due to the decreased degradation by proteosome but was enhanced at the mRNA level. Besides, cisplatin treatment activated the mammalian target of rapamycin (mTOR) pathway as shown by increased phosphorylation of Akt1, mTOR, S6K, and 4E-BP1, together with the elevated Livin. The PI3K inhibitor LY294002 inhibited both the phosphorylation of mTOR and upregulation of Livin. The stable overexpression of Livin inhibited the activation of caspase-3 and led to resistance to cisplatin, while the knockdown of Livin by siRNA rendered colon cancer cells more sensitive to cisplatin. Our study, along with others, highlighted the potential of Livin for cancer therapy in colon cancer.
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| 4. |
- Han, Xin-Bao, et al.
(författare)
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Ultrasmall Abundant Metal-Based Clusters as Oxygen-Evolving Catalysts
- 2019
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 141:1, s. 232-239
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Tidskriftsartikel (refereegranskat)abstract
- The oxygen evolution reaction is a crucial step in water electrolysis to develop clean and renewable energy. Although noble metal-based catalysts have demonstrated high activity for the oxygen evolution reaction, their application is limited by their high cost and low availability. Here we report the use of a molecule-to-cluster strategy for preparing ultrasmall trimetallic clusters by using the polyoxometalate molecule as a precursor. Ultrafine (0.8 nm) transition-metal clusters with controllable chemical composition are obtained. The transition-metal clusters enable highly efficient oxygen evolution through water electrolysis in alkaline media, manifested by an overpotential of 192 mV at 10 mA cm–2, a low Tafel slope of 36 mV dec–1, and long-term stability for 30 h of electrolysis. We note, however, that besides the excellent performance as an oxygen evolution catalyst, our molecule-to-cluster strategy provides a means to achieve well-defined transition-metal clusters in the subnanometer regime, which potentially can have an impact on several other applications.
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| 5. |
- Ji, Xuemei, et al.
(författare)
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Identification of susceptibility pathways for the role of chromosome 15q25.1 in modifying lung cancer risk
- 2018
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 9, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) identified the chromosome 15q25.1 locus as a leading susceptibility region for lung cancer. However, the pathogenic pathways, through which susceptibility SNPs within chromosome 15q25.1 affects lung cancer risk, have not been explored. We analyzed three cohorts with GWAS data consisting 42,901 individuals and lung expression quantitative trait loci (eQTL) data on 409 individuals to identify and validate the underlying pathways and to investigate the combined effect of genes from the identified susceptibility pathways. The KEGG neuroactive ligand receptor interaction pathway, two Reactome pathways, and 22 Gene Ontology terms were identified and replicated to be significantly associated with lung cancer risk, with P values less than 0.05 and FDR less than 0.1. Functional annotation of eQTL analysis results showed that the neuroactive ligand receptor interaction pathway and gated channel activity were involved in lung cancer risk. These pathways provide important insights for the etiology of lung cancer.
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| 6. |
- Liu, Wei, et al.
(författare)
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Impact of silver nanoparticles on human cells : effect of particle size
- 2010
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Ingår i: Nanotoxicology. - New York : Informa Healthcare. - 1743-5390 .- 1743-5404. ; 4:3, s. 319-330
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Tidskriftsartikel (refereegranskat)abstract
- This work investigated the cytotoxicities of three silver nanoparticles (SNPs) SNP-5, SNP-20 and SNP-50 with different sizes ( approximately 5 nm, approximately 20 nm and approximately 50 nm) using four human cell models (A549, SGC-7901, HepG2 and MCF-7). Endpoints included cell morphology, cell viability, cellular membrane integrity, oxidative stress and cell cycle progression. Observable deleterious effects on the cell morphologies and membrane integrity were induced by SNP-5 and SNP-20. SNPs elevated the ROS levels in cells and arrested the cells at S phase. Apoptosis occurred for 4-9% of the exposed cells. All these cellular responses as well as EC50 values were found to be size-dependent for the tested SNPs. Ultrastructural observations confirmed the presence of SNPs inside cells. Elemental analysis of silver in cells by ICP-MS showed that smaller nanoparticles enter cells more easily than larger ones, which may be the cause of higher toxic effects. The findings may assist in the design of SNP applications and provide insights into their toxicity.
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| 7. |
- Tao, Yong, et al.
(författare)
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Hollow fiber supported ionic liquid membrane microextraction for determination of sulfonamides in environmental water samples by high-performance liquid chromatography
- 2009
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Ingår i: Journal of Chromatography A. - : Elsevier. - 0021-9673 .- 1873-3778. ; 1216:35, s. 6259-6266
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Tidskriftsartikel (refereegranskat)abstract
- By using ionic liquid as membrane liquid and tri-n-octylphosphine oxide (TOPO) as additive, hollow fiber supported liquid phase microextraction (HF-LPME) was developed for the determination of five sulfonamides in environmental water samples by high-performance liquid chromatography with ultraviolet detection The extraction solvent and the parameters affecting the extraction enrichment factor such as the type and amount of carrier, pH and volume ratio of donor phase and acceptor phase, extraction time, salt-out effect and matrix effect were optimized. Under the optimal extraction conditions (organic liquid membrane phase: [C8MIM][PF6] with 14% TOPO (w/v); donor phase: 4mL, pH 4.5 KH2PO4 with 2M Na2SO4; acceptor phase: 25microL, pH 13 NaOH; extraction time: 8 h), low detection limits (0.1-0.4microg/L, RSDor=0.999) were obtained for all the analytes. The presence of humic acid (0-25mg/L dissolved organic carbon) and bovine serum albumin (0-100 μg/mL) had no significant effect on the extraction efficiency. Good spike recoveries over the range of 82.2-103.2% were obtained when applying the proposed method on five real environmental water samples. These results indicated that this present method was very sensitive and reliable with good repeatabilities and excellent clean-up in water samples. The proposed method confirmed hollow fiber supported ionic liquid membrane based LPME to be robust to monitoring trace levels of sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine and sulfamethoxazole in aqueous samples.
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