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3 results on '"secondary capping"'

1. The effect of secondary capping on the control of phosphorus release from sediment by activated thin-layer capping with Al-PIA.

Author

Zhu, Bolin, Li, Shuwen, Lin, Canyang, Liu, Shupo, Li, Fei, and Zhou, Zhenming

Subjects
PHOSPHORUS in water, SEDIMENT capping, PHOSPHORUS, SEDIMENT control
Abstract

It is well-known that the activated thin-layer capping covering by secondary capping of contaminated sediment poses a threat to the inactivation of activated material. In this study, the static simulation experiment was conducted to study the effect of secondary capping thickness by sediment on the control of TP release from the sediment by aluminum-based P-inactivation agent (Al-PIA), and to propose the phosphorus adsorption pathway of Al-PIA. The results showed that Al-PIA could effectively reduce the release of phosphorus pollutants from the sediment at the capping intensity of 2 kg/m2. When the secondary capping thickness of sediment were 0, 2, 4, 7, 10, and 15 mm, the average removal rates of TP were 87.57%, 76.39%, 61.22%, 51.32%, 41.93%, and 32.11%, respectively, indicating that the removal efficiency of phosphorus decreased with the increase of the secondary capping thickness of the sediment. The adsorbed phosphorus by Al-PIA was mainly non-apatite inorganic phosphorus (NAIP) in inorganic phosphorus. With the increase of the secondary capping thickness of sediment, the NAIP proportion of phosphorus adsorbed by Al-PIA increased. Meanwhile, the removal rate of phosphorus in the activated capping system showed a first increase and then decrease trend, and the removal rates of total phosphorus (TP), inorganic phosphorus (IP), and organic phosphorus (OP) were obvious except for that of organic phosphorus (OP). [ABSTRACT FROM AUTHOR]

Published
2021
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2. Nanoparticle Encapsulation Strategy: Leveraging Plant Exine Capsules Used as Secondary Capping for Oral Delivery.

Author

Wu D, Wang X, Wang S, Li B, and Liang H

Subjects
Administration, Oral, Capsules administration & dosage, Capsules chemistry, Delayed-Action Preparations administration & dosage, Delayed-Action Preparations chemistry, Drug Carriers chemistry, Drug Compounding, Drug Delivery Systems instrumentation, Flavones administration & dosage, Nanoparticles chemistry, Particle Size, Tannins chemistry, Zein chemistry, Drug Delivery Systems methods, Flavones chemistry, Helianthus chemistry, Pollen chemistry
Abstract

Protein-based nanoparticles (NPs) with favorable properties including enhanced absorptivity and low toxicity still suffer a major challenge for rapid nutraceutical or drug release after oral administration. Hence, we introduced a secondary encapsulation for unstable factor to attain a controlled-release effect in a gastrointestinal environment. In this work, assembled nanoparticles engineered by nobiletin (NOB), zein, and tannin acid (TA) were first reported for drug delivery systems. The TA added was capable of obtaining further assembly to stabilize nobiletin in comparison with NOB-loaded zein NPs only. Sunflower pollens (SPGs) were selected as carriers for further oral delivery, while zein was chosen as a coating material for capping SPGs absolutely. As a result, the NOB/zein/TA NPs (NZT NPs) obtained had a stable size of 100 nm after 48 h. Besides, they could improve the chemical stability of NOB for at least 120 days at 4 °C compared with zein NPs (ZT NPs). Owing to the secondary capping by SPGs, the final system was able to release selectively via an oral route, that is, achieving no release in a gastric environment and slow release in an intestine environment. Generally, our research proposed a secondary protection model to prevent drug-loaded NPs from resolving after oral administration, which provided a new perspective for nutraceutical or drug encapsulation and controlled-release delivery.

Published
2019
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3. New Insights into the Biochemistry and Cell Biology of RNA Recapping

Author

Trotman, Jackson B.

Subjects
Biochemistry, Cellular Biology, Molecular Biology, RNA, mRNA, recapping, cytoplasmic capping, secondary capping, 5 cap, RNA processing, RNA decay, post-transcriptional gene regulation, translational control, transcriptome, RNMT, methyltransferase, CE, capping enzyme, activity assay, proteomics, HSP90
Abstract

Eukaryotic gene expression depends on the 5' cap structure added to all mRNAs. The biology of RNA capping is more dynamic than originally thought, with cytoplasmic recapping enabling spatial and temporal control of translation and other aspects of the RNA life cycle. Despite progress over the past decade, critical gaps remain in our understanding of the biochemistry of RNA recapping and its context within the cell, which are addressed in this dissertation.Recapping an uncapped RNA in the cytoplasm begins with the combined activities of a 5' monophosphate RNA kinase and capping enzyme (CE). Recapped RNAs are also methylated at the N7 position of the cap guanine, enabling recognition by cap-binding proteins such as the translation initiation factor eIF4E. However, it was unknown how caps synthesized in the cytoplasm acquire this critical methyl group. Here I describe the identification of the enzyme that completes the synthesis of mature caps in the cytoplasm. This enzyme, RNA guanine-7 methyltransferase (RNMT), was originally thought to be restricted to the nucleus, but I show that it also functions in the cytoplasm. Cytoplasmic RNMT activity is unexpectedly robust compared to that of nuclear RNMT, and RNMT knockdown points to RNMT being the predominant, if not only cap guanine-N7 methyltransferase in the cytoplasm. These results were obtained using an adapted cap methyltransferase activity assay, the details of which are provided. RNMT directly interacts with CE through its C-terminal catalytic domain, allowing it to associate with the multifunctional cytoplasmic capping complex. Cytoplasmic RNMT activity is additionally stimulated by dimerization with the small protein cofactor RAM. Inhibiting cytoplasmic cap methylation with a dominant-negative form of RNMT caused recapping target RNAs to destabilize, suggesting surveillance by decapping enzymes specific for unmethylated caps.The full complement of proteins required for cytoplasmic recapping is also unknown. Toward this end, I used in vivo crosslinking and bottom-up proteomics to identify novel proteins that interact with the cytoplasmic population of capping enzyme. The identified proteins perform diverse functional roles and include metabolic enzymes, nucleocytoplasmic transporters, and cytoskeletal proteins. Many of these proteins are known to bind mRNA and may underlie the observed specificity of recapping target RNAs. Western blotting confirmed the association of cytoplasmic CE with the candidate interactors FASN, XPO2, HSP90, EEF2, RUVBL1, and RUVBL2. Further investigation of HSP90 revealed that its interaction with CE causes stabilization of the levels of both nuclear and cytoplasmic CE. HSP90 stabilization may provide a link between cytoplasmic recapping and the cellular stress response, which is discussed.

Published
2018

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