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Effect of the Inorganic Nitrogen Source in the Expression of Nitrite Reductase (NirA) in <i>Thermosynechococcus elongatus</i>bp-1

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Advances in Microbiology 2014年第15期4卷 1044-1056页

作者： Maite Buxens María J. Llama Juan L. Serra Enzyme and Cell Technology Group Department of Biochemistry and Molecular Biology Faculty of Science and Technology University of the Basque Country (UPV/EHU) Bilbao Spain

Nitrite reductase (NirA, EC 1.***.7.1) from the thermophilic, unicellular, non-N2-fixing cyanobacte-rium Thermosynechococcus elongatus bp-1 has been cloned and expressed in Escherichia coli. Analysis by SDS-PAGE of the pure recombinant protein (His6NirA) showed two protein bands, one of 58 kDa (corresponding to the theoretical His6NirA molecular mass) and another of 44 kDa. Western blotting and mass spectrometry analyses confirmed that the 44 kDa protein resulted from proteolysis of the intact His6NirA, and suggested the existence, at the C-terminal domain of the 58 kDa form, of a region particularly sensible to proteolysis or accessible to proteases. A sample of both forms of His6NirA was used to obtain anti-NirA polyclonal antibodies. These antibodies were used to assess, by SDS-PAGE followed by Western blotting, the in vivo expression of NirA in wild-type cells of T. elongatus bp-1 growing in cultures with nitrate, nitrite or ammonium which were inoculated with cells grown with different nitrogen sources. These analyses revealed that protein bands corresponding to the complete (58 kDa) and truncated (44 kDa) forms of NirA can also be detected in solubilized cells. Moreover, the presence of each of these forms depended on the nitrogen source used to grow cells. Thus, expression of the complete NirA generally predominates in cells growing in medium with nitrate or nitrite. However, the truncated form prevails in cells grown in nitrate or nitrite and then transferred to medium with ammonium. The fact that the patterns of in vivo expression of NirA are different depending on the nitrogen source used possibly relies on a post-translational regulatory mechanism by proteolysis.

关键词： Cyanobacteria NirA Nitrite Reductase Expression Post-Translational Regulation Protein Hydrolysis Thermosynechococcus elongatus bp-1

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Shewanella haliotis bp-1海藻酸裂解酶基因的克隆表达

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广西科学 2016年第3期23卷 228-233页

作者：黄桂媛温顺华李锋卢明倩王巧贞廖威黄庶识广西科学院生物物理实验室广西南宁530007 厦门万泰凯瑞生物技术有限公司福建厦门361003 黔南州民族师范学院化学化工学院贵州都匀558000 广西职业技术学院广西南宁530226

【目的】了解海洋细菌Shewanella haliotis B P-1中海藻酸裂解酶降解海藻酸钠的生物活性。【方法】应用基因克隆和大肠杆菌异源表达技术,过量表达海藻酸裂解酶,将粗酶液通过 DEAE Sepharose FF柱分离纯化后检测其酶活性。【结果】从*** ... 详细信息

【目的】了解海洋细菌Shewanella haliotis B P-1中海藻酸裂解酶降解海藻酸钠的生物活性。【方法】应用基因克隆和大肠杆菌异源表达技术,过量表达海藻酸裂解酶,将粗酶液通过 DEAE Sepharose FF柱分离纯化后检测其酶活性。【结果】从*** bp-1菌株的基因组DNA中克隆得到一个大小为2157 bp的海藻酸裂解酶基因Alg17S ,该基因编码的海藻酸裂解酶 Alg17S属于PL17家族的蛋白,大小为79726 Da,其中包括N端26个氨基酸的信号肽,与Saccharophagus degradans 2-40菌株产生的海藻酸裂解酶 Alg17C 具有高度同源性,相似性为52%。经纯化后获得的重组酶 Alg17S和△snAlg17S（N端不含26个氨基酸的信号肽）均具有降解海藻酸钠的活性,但△snAlg17S对海藻酸钠的催化活性比 Alg17S高,其酶比活力高达9635 U/mg。【结论】重组海藻酸裂解酶△snAlg17S兼具高表达水平及高酶活性,是进一步研究海藻酸盐糖化和生物燃料生产的潜在的优势酶。

关键词：海藻酸裂解酶克隆表达酶活性测定 Shewanella haliotis bp-1

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Highly stable carbon-coated nZVI composite Fe0@RF-C for efficient degradation of emerging contaminants

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Environmental Science and Ecotechnology 2024年第6期22卷 233-244页

作者： Guizhou Xu Lin Sun Yizhou Tu Xiaolei Teng Yumeng Qi Yaoyao Wang Aimin Li Xianchuan Xie Xueyuan Gu State Key Laboratory of Pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing210023China Key Laboratory of Poyang Lake Environment and Resource Utilization Engineering Research Center of Watershed Carbon NeutralizationMinistry of EducationSchool of Resource and EnvironmentNanchang UniversityNanchang330031China Nanjing University&Yancheng Academy of Environment Protection Technology and Engineering Nanjing210023China Jiangxi Nanxin Environmental Protection Technology Co.LTD Jiujiang CityJiangxi Province330300China

Nanoscale zerovalent iron(nZVI)has garnered significant attention as an efficient advanced oxidation activator,but its practical application is hindered by aggregation and *** nZVI with carbon can effectively addresses these issues.A simple and scalable production method for carbon-coated nZVI composite is highly *** anti-oxidation and catalytic performance of carbon-coated nZVI composite merit in-depth *** this study,a highly stable carbon-coated core-shell nZVI composite(Fe0@RF-C)was successfully prepared using a simple method combining phenolic resin embedding and carbothermal ***0@RF-C was employed as a heterogeneous persulfate(PS)activator for degrading 2,4-dihydroxybenzophenone(bp-1),an emerging *** to commercial nZVI,Fe0@RF-C exhibited superior PS activation performance and oxidation *** 95%of bp-1 was removed within 10 min in the Fe0@RF-C/PS *** carbon layer promotes the enrichment of bp-1 and accelerates its degradation through singlet oxygen oxidation and direct electron transfer *** study provides a straightforward approach for designing highly stable carbon-coated nZVI composite and elucidates the enhanced catalytic performance mechanism by carbon layers.

关键词： Nanoscale zerovalent iron Carbon-coated nZVI Persulfate bp-1 Enhanced degradation

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