| 1. |
- Chang, Yue, et al.
(författare)
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Cd-Metallothioneins in Three Additional Tetrahymena Species : Intragenic Repeat Patterns and Induction by Metal Ions
- 2014
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Ingår i: Journal of Eukaryotic Microbiology. - : Wiley. - 1066-5234 .- 1550-7408. ; 61:4, s. 333-342
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Tidskriftsartikel (refereegranskat)abstract
- Ciliate metallothioneins (MTs) possess many unique features compared to the "classic" MTs in other organisms, but they have only been studied in a small number of species. In this study, we investigated cDNAs encoding subfamily 7a metallothioneins (CdMTs) in three Tetrahymena species (T. hegewischi, T. malaccensis, and T. mobilis). Four CdMT genes (ThegMT1, ThegMT2, TmalMT1, and TmobMT1) were cloned and characterized. They share high sequence similarity to previously identified subfamily 7a MT members. Tetrahymena CdMTs exhibit a remarkably regular intragenic repeat homology. The CdMT sequences were divided into two main types of modules, which had been previously described, and which we name "A" and "B". ThegMT2 was identified as the first MT isoform solely composed of module "B". A phylogenetic analysis of individual modules of every characterized Tetrahymena CdMT rigorously documents the conclusion that modules are important units of CdMT evolution, which have undergone frequent and rapid gain/loss and shuffling. The transcriptional activity of the four newly identified genes was measured under different heavy metal exposure (Cd, Cu, Zn, Pb) using real-time quantitative PCR. The results showed that these genes were differentially induced after short (1 h) or long (24 h) metal exposure. The evolutionary diversity of Tetrahymena CdMTs is further discussed with regard to their induction by metal ions.
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| 2. |
- Kang, Ying, et al.
(författare)
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Weak Bonds Joint Effects Catalyze the Cleavage of Strong C−C Bond of Lignin‐Inspired Compounds and Lignin in Air by Ionic Liquids
- 2020
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Ingår i: ChemSusChem. - : John Wiley & Sons. - 1864-5631 .- 1864-564X. ; 13:22, s. 5945-5953
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Tidskriftsartikel (refereegranskat)abstract
- Oxidation of lignin to value‐added aromatics through selective C−C bond cleavage via metal‐free and mild strategies is promising but challenging. It was discovered that the cations of ionic liquids (ILs) could effectively catalyze this kind of strong bond cleavage by forming multiple weak hydrogen bonds, enabling the reaction conducted in air at temperature lower than 373 K without metal‐containing catalysts. The cation [CPMim]+ (1‐propylronitrile‐3‐methylimidazolium) afforded the highest efficiency in C−C bond cleavage, in which high yields (>90 %) of oxidative products were achieved. [CPMim]+ could form three ipsilateral hydrogen bonds with the oxygen atom of C=O and ether bonds at both sides of the C−C bond. The weak bonds joint effects could promote adjacent C−H bond cleave to form free radicals and thereby catalyze the fragmentation of the strong C−C. This work opens up an eco‐friendly and energy‐efficient route for direct valorization of lignin by enhancing IL properties via tuning the cation.
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| 3. |
- Zhang, Xueyi, et al.
(författare)
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Synthesis of Self-Pillared Zeolite Nanosheets by Repetitive Branching
- 2012
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 336:6089, s. 1684-1687
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Tidskriftsartikel (refereegranskat)abstract
- Hierarchical zeolites are a class of microporous catalysts and adsorbents that also contain mesopores, which allow for fas transport of bulky molecules and thereby enable improved performance in petrochemical and biomass processing. We used repetitive branching during one-step hydrothermal crystal growth to synthesize a new hierarchical zeolite made of orthogonally connected microporous nanosheets. The nanosheets are 2 nanometers thick and contain a network of 0.5-nanometer micropores. The house-of-cards arrangement of the nanosheets creates a permanent network of 2- to 7-nanometer mesopores, which, along with the high external surface area and reduced micropore diffusion length, account for higher reaction rates for bulky molecules relative to those of other mesoporous and conventional MFI zeolites.
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