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941.
942.
Suya Zhao Yuanyuan Zhao Hanxiao Liang 《International journal of phytoremediation》2019,21(13):1296-1304
AbstractUptake and in-plant transport of formaldehyde by six plants with or without soil microorganisms were investigated. The capabilities of fresh and boiled leaf extracts to dissipate added formaldehyde were also measured to evaluate formaldehyde metabolism in plant tissues. Results show that when the initial formaldehyde level in air was 0.56?±?0.04?mg·m?3, the removal rate in the plant-only systems varied from 1.91 to 31.8?μg·h?1·g?1 FW (fresh weight). The removal rate of plants in the plant-only systems were ordered as Helianthus annuus Linn > Lycopersicon esculentum Miller > Oryza sativa > Sansevieria trifasciata Prain > Bryophyllum pinnatum > Mesembryanthemum cordifolium L. f. Most reduction of formaldehyde in the air was due to degradation by active components in the plant tissues, of which 4–64% of these were through to be enzymatic reactions. In the microbe-plant systems, formaldehyde removal rates increased by 0.24–9.53 fold compared to the plant-only systems, with approximately 19.6–90.5% of the formaldehyde reduction resulting from microbial degradation. Microorganisms added to the rhizosphere solution enhanced phytoremediation by increasing the downward transport of formaldehyde and its release by roots. Results suggest a new means to screen for efficient plant species that can be used for phytoremediation of indoor air. 相似文献
943.
Chemical investigation of the Xisha soft coral Sarcophyton sp. has led to the isolation of eight cembrane-type diterpenoids, including three new compounds, namely sarcophynoids A-C ( 1 – 3 ), and five known analog compounds ( 4 – 8 ). Their structures were clarified based on spectroscopic analysis, and computer-assisted methods including TDDFT-ECD calculation and the quantum mechanical-nuclear magnetic resonance (QM-NMR) method. All the above compounds were tested for their antibacterial activities. Among them, compounds 4 – 7 and 8 exhibited antibacterial activities against S. aureus, B. subtilis, and P. aeruginosa, with MIC of 4–64 μg/mL. 相似文献
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946.
The effect of DNA base composition on the kinetics of the association between DNA and proflavine has been investigated using the temperature jump relaxation method. It is found that, regardless of the G + C base composition the results fit a two step mechanism, the second of which exhibits characteristics of intercalation of proflavine into DNA. However, they two equilibrium constants corresponding to these steps, KI and KII, depend on the nature of the DNAs. The constant KI is found to be an order of magnitude greater for M. lysodeikticus DNA (72% G + C) than for calf thymus DNA (48% G + C). Increasing G-C content thus appears to favor the intermediate non-intercalated complex of proflavine with DNA. Methylation of M. lysodeikticus DNA with dimethyl sulfate, preferentially yielding N7 methyl guanine as the modified base, again leads to an apparent two step mechanism, with the value of KI unchanged with respect to untreated DNA, while the affinity of proflavine for the intercalated complex measured by the value of KII increases for methylated DNA. 相似文献
947.
Yu-Jie Chen Yu-Chien Chuang Chi-Ning Chuang Yun-Hsin Cheng Chuang-Rung Chang Chih-Hsiang Leng Ting-Fang Wang 《Nucleic acids research》2016,44(5):2199-2213
Double-strand breaks (DSBs) in chromosomes are the most challenging type of DNA damage. The yeast and mammalian Mre11-Rad50-Xrs2/Nbs1 (MRX/N)-Sae2/Ctp1 complex catalyzes the resection of DSBs induced by secondary structures, chemical adducts or covalently-attached proteins. MRX/N also initiates two parallel DNA damage responses—checkpoint phosphorylation and global SUMOylation—to boost a cell''s ability to repair DSBs. However, the molecular mechanism of this SUMO-mediated response is not completely known. In this study, we report that Saccharomyces cerevisiae Mre11 can non-covalently recruit the conjugated SUMO moieties, particularly the poly-SUMO chain. Mre11 has two evolutionarily-conserved SUMO-interacting motifs, Mre11SIM1 and Mre11SIM2, which reside on the outermost surface of Mre11. Mre11SIM1 is indispensable for MRX assembly. Mre11SIM2 non-covalently links MRX with the SUMO enzymes (E2/Ubc9 and E3/Siz2) to promote global SUMOylation of DNA repair proteins. Mre11SIM2 acts independently of checkpoint phosphorylation. During meiosis, the mre11SIM2 mutant, as for mre11S, rad50S and sae2Δ, allows initiation but not processing of Spo11-induced DSBs. Using MRX and DSB repair as a model, our work reveals a general principle in which the conjugated SUMO moieties non-covalently facilitate the assembly and functions of multi-subunit protein complexes. 相似文献
948.
It is shown that the binding of anti-nucleoside antibodies to fixed human metaphase chromosomes can be revealed using the immunoperoxidase procedure while under the same conditions no antibody binding is revealed using the immunofluorescence procedure. 相似文献
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950.