Removal mechanism and quantitative control of trichloroethylene in a post-plasma-catalytic system over Mn–Ce/HZSM-5 catalysts

2021 ◽  
Author(s):  
Tian Chang ◽  
Qingcai Chen ◽  
Hao Fan ◽  
Zhenxing Shen ◽  
Bin Zhang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Removal Mechanism ◽  
Tce Degradation

The optimization of the TCE degradation process was achieved and the TCE degradation pathway in the PPC system was proposed.

scholarly journals The Role of Chaperone-Mediated Autophagy in Hepatitis C Virus-Induced Pathogenesis

2021 ◽  
Vol 11 ◽  
Author(s):  
Chieko Matsui ◽  
Putu Yuliandari ◽  
Lin Deng ◽  
Takayuki Abe ◽  
Ikuo Shoji
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Hepatocyte Nuclear Factor ◽  
Selective Degradation ◽  
Substrate Protein ◽  
Hepatocyte Nuclear Factor 1Α ◽  
Chaperone Mediated Autophagy

Lysosome incorporate and degrade proteins in a process known as autophagy. There are three types of autophagy; macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA). Although autophagy is considered a nonselective degradation process, CMA is known as a selective degradation pathway. All proteins internalized in the lysosome via CMA contain a pentapeptide KFERQ-motif, also known as a CMA-targeting motif, which is necessary for selectivity. CMA directly delivers a substrate protein into the lysosome lumen using the cytosolic chaperone HSC70 and the lysosomal receptor LAMP-2A for degradation. Hepatitis C virus (HCV) NS5A protein interacts with hepatocyte-nuclear factor 1α (HNF-1α) together with HSC70 and promotes the lysosomal degradation of HNF-1α via CMA, resulting in HCV-induced pathogenesis. HCV NS5A promotes recruitment of HSC70 to the substrate protein HNF-1α. HCV NS5A plays a crucial role in HCV-induced CMA. Further investigations of HCV NS5A-interacting proteins containing CMA-targeting motifs may help to elucidate HCV-induced pathogenesis.

scholarly journals Steroid Degradation in Comamonas testosteroni TA441: Identification of the Entire β-Oxidation Cycle of the Cleaved B Ring

2019 ◽  
Vol 85 (20) ◽  
Author(s):  
Masae Horinouchi ◽  
Hiroyuki Koshino ◽  
Michal Malon ◽  
Hiroshi Hirota ◽  
Toshiaki Hayashi
Keyword(s):  
Gene Clusters ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Comamonas Testosteroni ◽  
Content Type ◽  
Coa Transferase ◽  
Degrading Bacteria ◽  
Globally Distributed

ABSTRACT Comamonas testosteroni TA441 degrades steroids via aromatization of the A ring, followed by degradation of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid, mainly by β-oxidation. In this study, we revealed that 7β,9α-dihydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostanoic acid-coenzyme A (CoA) ester is dehydrogenated by (3S)-3-hydroxylacyl CoA-dehydrogenase, encoded by scdE (ORF27), and then the resultant 9α-hydroxy-7,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid-CoA ester is converted by 3-ketoacyl-CoA transferase, encoded by scdF (ORF23). With these results, the whole cycle of β-oxidation on the side chain at C-8 of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid is clarified; 9-hydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid-CoA ester is dehydrogenated at C-6 by ScdC1C2, followed by hydration by ScdD. 7β,9α-Dihydroxy-17-oxo-1,2,3,4,10,19-hexanorandrostanoic acid-CoA ester then is dehydrogenated by ScdE to be converted to 9α-hydroxy-17-oxo-1,2,3,4,5,6,10,19-octanorandrostan-7-oic acid-CoA ester and acetyl-CoA by ScdF. ScdF is an ortholog of FadA6 in Mycobacterium tuberculosis H37Rv, which was reported as a 3-ketoacyl-CoA transferase involved in C ring cleavage. We also obtained results suggesting that ScdF is also involved in C ring cleavage, but further investigation is required for confirmation. ORF25 and ORF26, located between scdF and scdE, encode enzymes belonging to the amidase superfamily. Disrupting either ORF25 or ORF26 did not affect steroid degradation. Among the bacteria having gene clusters similar to those of tesB to tesR, some have both ORF25- and ORF26-like proteins or only an ORF26-like protein, but others do not have either ORF25- or ORF26-like proteins. ORF25 and ORF26 are not crucial for steroid degradation, yet they might provide clues to elucidate the evolution of bacterial steroid degradation clusters. IMPORTANCE Studies on bacterial steroid degradation were initiated more than 50 years ago primarily to obtain materials for steroid drugs. Steroid-degrading bacteria are globally distributed, and the role of bacterial steroid degradation in the environment as well as in relation to human health is attracting attention. The overall aerobic degradation of the four basic steroidal rings has been proposed; however, there is still much to be revealed to understand the complete degradation pathway. This study aims to uncover the whole steroid degradation process in Comamonas testosteroni TA441 as a model of steroid-degrading bacteria. C. testosteroni is one of the most studied representative steroid-degrading bacteria and is suitable for exploring the degradation pathway, because the involvement of degradation-related genes can be determined by gene disruption. Here, we elucidated the entire β-oxidation cycle of the cleaved B ring. This cycle is essential for the following C and D ring cleavage.

scholarly journals Degradation of the antibiotic ornidazole in aqueous solution by using nanoscale zero-valent iron particles: kinetics, mechanism, and degradation pathway

RSC Advances ◽  
2018 ◽  
Vol 8 (61) ◽  
pp. 35062-35072 ◽  
Author(s):  
Yanchang Zhang ◽  
Lin Zhao ◽  
Yongkui Yang ◽  
Peizhe Sun
Keyword(s):  
Aqueous Solution ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Zero Valent Iron ◽  
Main Mechanism ◽  
Iron Particles ◽  
Nanoscale Zero Valent Iron ◽  
Nitro Reduction

The whole possible process of ONZ removal by nZVI. The reduction on the surface of nZVI was the main mechanism. A potential pathway including dechlorination, nitro reduction, N-denitration, and cleavage was proposed for the degradation process.

Sonochemical Degradation of Sodium Dodecylbenzene Sulfonate in Aqueous Solutions

2003 ◽  
Vol 56 (10) ◽  
pp. 1045 ◽  
Author(s):  
Muthupandian Ashokkumar ◽  
Tyson Niblett ◽  
Lyndon Tantiongco ◽  
Franz Grieser
Keyword(s):  
Initial Step ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Water Soluble ◽  
Sodium Dodecylbenzene Sulfonate ◽  
Gaseous Hydrocarbon ◽  
Dodecylbenzene Sulfonate ◽  
Volatile Products ◽  
Degradation Step ◽  
Radical Attack

The sonochemical degradation of sodium dodecylbenzene sulfonate (SDBS) has been studied over a wide concentration range spanning the critical micelle concentration (CMC) of the surfactant. The rate of degradation of SDBS increased linearly with increasing concentration below the CMC of SDBS. Above the CMC, the degradation rate continued to increase but at a much slower rate compared with that below the CMC. It was found that the increasing rate of degradation of SDBS correlated closely with the decrease in the air/water surface tension of the surfactant solutions. The results of this study strongly suggest that the initial step in the degradation process is OH• radical attack onto SDBS molecules adsorbed at the cavitation bubble/solution interface. The sonication of SDBS solutions for extended periods of time (ca. 12 h) led to the generation of gaseous hydrocarbon products, such as methane, ethane, ethylene, and acetylene. It is concluded that further radical attack occurs on the intermediates produced from the initial degradation step. This further degradation pathway is responsible for producing both water-soluble species, and volatile products that are pyrolyzed within the cavitation bubbles.

Identification and targeted disruption of the gene encoding the main 3-ketosteroid dehydrogenase in Mycobacterium smegmatis

Microbiology ◽  
2005 ◽  
Vol 151 (7) ◽  
pp. 2393-2402 ◽  
Author(s):  
Anna Brzostek ◽  
Tomasz Śliwiński ◽  
Anna Rumijowska-Galewicz ◽  
Małgorzata Korycka-Machała ◽  
Jarosław Dziadek
Keyword(s):  
Mycobacterium Smegmatis ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Ring Structure ◽  
Wild Type ◽  
Targeted Disruption ◽  
Gene Encoding ◽  
Key Enzymes ◽  
Catabolic Potential ◽  
Partial Inactivation

The catabolic potential for sterol degradation of fast-growing mycobacteria is well known. However, no genes or enzymes responsible for the steroid degradation process have been identified as yet in these species. One of the key enzymes required for degradation of the steroid ring structure is 3-ketosteroid Δ1-dehydrogenase (KsdD). The recent annotation of the Mycobacterium smegmatis genome (TIGR database) revealed six KsdD homologues. Targeted disruption of the MSMEG5898 (ksdD-1) gene, but not the MSMEG4855 (ksdD-2) gene, resulted in partial inactivation of the cholesterol degradation pathway and accumulation of the intermediate 4-androstene-3,17-dione. This effect was reversible by the introduction of the wild-type ksdD-1 gene into M. smegmatis ΔksdD-1 or overexpression of ksdD-2. The data indicate that KsdD1 is the main KsdD in M. smegmatis, but that KsdD2 is able to perform the cholesterol degradation process when overproduced.

Visible Light Photocatalytic Degradation of Methylene Blue over N-Doped TiO2

2014 ◽  
Vol 609-610 ◽  
pp. 141-146 ◽  
Author(s):  
Yu Long Hu ◽  
Li Qing Zhou ◽  
Hong Fang Liu ◽  
Xing Peng Guo
Keyword(s):  
Methylene Blue ◽  
Nitrogen Atom ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Functional Group ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Methyl Group ◽  
Intermediate Products ◽  
Visible Light Photocatalytic

The visible light photocatalytic degradation of methylene blue (MB) over N-doped TiO2 (N-TiO2) was investigated. The intermediate products of MB in the photocatalytic degradation process were analyzed by HPLC-MS technique. The results show that the cleavages of CS+=C and CN=C functional group in the central aromatic ring and the cleavage of N-C bond between the methyl group and nitrogen atom all can occur in the visible light photocatalytic degradation process over N-TiO2, but MB is difficult to be mineralized completely to the inorganic products. A detailed degradation pathway of MB has been proposed on the basis of a careful identification of intermediate products.

scholarly journals Role of Sec61p in the ER-associated degradation of short-lived transmembrane proteins

2008 ◽  
Vol 181 (7) ◽  
pp. 1095-1105 ◽  
Author(s):  
Daniel C. Scott ◽  
Randy Schekman
Keyword(s):  
Degradation Process ◽  
Ubiquitin Proteasome System ◽  
Degradation Pathway ◽  
Specific Protein ◽  
Cysteine Residue ◽  
Misfolded Proteins ◽  
Er Quality Control ◽  
Substrate Protein ◽  
Ubiquitin Proteasome ◽  
Protein Components

Misfolded proteins in the endoplasmic reticulum (ER) are identified and degraded by the ER-associated degradation pathway (ERAD), a component of ER quality control. In ERAD, misfolded proteins are removed from the ER by retrotranslocation into the cytosol where they are degraded by the ubiquitin–proteasome system. The identity of the specific protein components responsible for retrotranslocation remains controversial, with the potential candidates being Sec61p, Der1p, and Doa10. We show that the cytoplasmic N-terminal domain of a short-lived transmembrane ERAD substrate is exposed to the lumen of the ER during the degradation process. The addition of N-linked glycan to the N terminus of the substrate is prevented by mutation of a specific cysteine residue of Sec61p, as well as a specific cysteine residue of the substrate protein. We show that the substrate protein forms a disulfide-linked complex to Sec61p, suggesting that at least part of the retrotranslocation process involves Sec61p.

Phragmites australis peroxidases role in the degradation of an azo dye

2007 ◽  
Vol 56 (3) ◽  
pp. 263-269 ◽  
Author(s):  
C.C. Carias ◽  
J.M. Novais ◽  
S. Martins-Dias
Keyword(s):  
Phragmites Australis ◽  
Textile Industry ◽  
Specific Activity ◽  
Industrial Effluents ◽  
Active Role ◽  
Degradation Process ◽  
Degradation Pathway ◽  
Acid Orange 7

Phragmites australis are commonly used in constructed wetlands either for domestic sewage or industrial effluents treatment. The aerobic mineralization mechanisms of Acid Orange 7, AO7, in a Vertical Flow Constructed Wetland (VFCW) planted with P. australis suggest that AO7 degradation pathway may involve enzymes like peroxidases (POD), known to degrade some recalcitrant pollutants. In this context, the aim of this study was to evaluate the role of POD extracted from the VFCW P. australis leaves in the decolourization of AO7, which belongs to the very restricted group of bio-degradable azo dyes and is widely used in the textile industry. Leaves' crude extract (CE) was purified by protein fractioning with ammonium sulphate (20–80%). AO7 (0.14 mM) decolourization rate of each CE fraction was determined using hydrogen peroxide (0.2 mM) as a co-substrate. A maximum specific activity of 6.8 × 10−3 μmol QNNM min−1 mg protein−1 was obtained for the 40–60% fraction. The results obtained suggest that P. australis may be a good candidate for the treatment of AO7 contaminated effluents in a VFCW, as very high removal efficiencies were achieved at pilot scale and in vitro studies leading to the decolourization of the dye, suggesting a positive and active role of P. australis in the removal mechanisms within the VFCW. Moreover, some questions were put forward regarding the participation of other important plant enzymes in the degradation process.

scholarly journals Oxidative degradation of p-chlorophenol by the persulfate-doped Fe-Mn bimetallic hydroxide, the parametrical significance, and systematical optimization

2021 ◽  
Author(s):  
Tao Huang ◽  
Jing Du ◽  
Danni Yu ◽  
Shihan Deng ◽  
Shuwen Zhang ◽  
...  
Keyword(s):  
Catalytic System ◽  
Organic Contaminants ◽  
Oxidative Degradation ◽  
Degradation Process ◽  
Catalytic Degradation ◽  
Molar Ratio ◽  
Order Kinetic ◽  
Valence Transition ◽  
Order Kinetic Model ◽  
Oxidation Performance

Abstract Aqueous Fe(II)-catalyzed activation commonly deteriorates the oxidation performance of persulfate (PS) to the treatment of organic contaminants. In this study, a PS-doped layered bimetallic hydroxide (Fe-Mn hydroxide) was synthesized to construct a heterogeneously catalytic system to solve the issue brought by homogeneity. The molar ratio of Fe(II) to Mn(II) and the mass ratio of PS to Fe-Mn hydroxide both had a significant impact on the catalytic degradation of p-CP. Reaction temperatures engaged in the most essential role in influencing the degradation and removal of p-chlorophenol (p-CP). The optimal combination of factors for the preparation of PS-hydroxide and the treatment of p-CP was finally determined by significance analysis. The degradation process was appropriately fitted by the pseudo-first-order kinetic model. the benzene ring in p-CP was broken by PS-hydroxide during the adsorption. The surface modification of PS-hydroxide caused by the valence transition of Mn was beneficial to the adsorption and catalytic degradation of p-CP.CapsuleA persulfate-doped layered bimetallic hydroxide was synthesized to construct a heterogeneously catalytic system to solve the drawback of homogeneity for the effective treatment of p-chlorophenol.

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