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关键词： Tyrosinase   Bacillus aryabhattai   Characterization   Decolorization   Application  

摘要： Although lots of tyrosinases have been isolated from bacteria, few studies are focused on tyrosinases from Bacillus sp.. In this study, a tyrosinase from B. aryabhattai TCCC 111983 (TYR) was functionally expressed, purified, and then biochemically characterized. The recombinant tyrosinase (rTYR) presented a good catalytic activity in a broad temperature and pH range, retaining over 60% of the relative activity at 30 degrees C-90 degrees C and 45% at pH 3.0 to 10.0. Especially, rTYR exhibited 20% of its maximum activity at 0 degrees C, and it also showed a variable stability towards different effectors. It presented high tolerance towards salinity and chloride, retaining 81% of its original activity in 2 M NaCl. Kinetic parameters indicated that rTYR displayed a relatively good affinity for both L-tyrosine and L-DOPA. Additionally, rTYR demonstrated remarkable advantages on efficient decolorizing azo and anthraquinonic food dyes (carmine and erythrosin), and more five industrial dyes with or without mediators in acidic, neutral, and alkaline conditions. As the first report on the tyrosinase from B. aryabhattai, the aforementioned results indicated that rTYR would be potential for food industrial applications. (c) 2021 Elsevier B.V. All rights reserved.

关键词： Flavivirus   Cryo-EM   Antibody   Structural biology   Dengue   Zika  

摘要： Flaviviruses are the fastest spreading arthropod-borne viruses that cause severe symptoms such as hepatitis, hemorrhagic fever, encephalitis, and congenital deformities. Nearly 40 % of the entire human population is at risk of flavivirus epidemics. Yet, effective vaccination is restricted only to a few flaviviruses such as yellow fever and Japanese encephalitis viruses, and most recently for select cases of dengue virus infections. Despite the global spread of dengue virus, and emergence of new threats such as Zika virus and a new genotype of Japanese encephalitis virus, insights into flavivirus targets for potentially broad-spectrum vaccination are limited. In this review article, we highlight biochemical and structural differences in flavivirus proteins critical for virus as-sembly and host interactions. A comparative sequence analysis of pH-responsive properties of viral structural proteins identifies trends in conservation of complementary acidic-basic character between interacting viral structural proteins. This is highly relevant to the understanding of pH-sensitive differences in virus assembly in organelles such as neutral ER and acidic Golgi. Surface residues in viral interfaces identified by structural ap-proaches are shown to demonstrate partial conservation, further reinforcing virus-specificity in assembly and interactions with host proteins. A comparative analysis of epitope conservation in emerging flaviviruses iden-tifies therapeutic antibody candidates that have potential as broad spectrum anti-virals, thus providing a path towards development of vaccines.

关键词： Nitrate reductase   Total soluble carbohydrates   Proline   Sucrose   Reducing sugars  

摘要： Virola surinamensis is a forest species widely distributed in the estuaries of the Amazon. These ecosystems are susceptible to contamination by Cadmium (Cd), indicating that the plant has strategies for tolerating this metal. The aim of this study was to assess the nitrogen and carbon metabolism of young plants of Ucuúba (Virola surinamensis) in the presence of cadmium with the perspective of the phytoremediation of contaminated environments. The used experimental design was a completely randomized design with five Cd concentrations (0, 15, 30, 45, and 60 mg L− 1), for 60 days. In general, Cd did not affect nitrate concentration in the root but had a positive effect on leaves. The reduction of nitrate reductase (NR) in plants exposed to Cd was followed by a decrease in ammonia, total soluble amino acids (TSA), and total soluble proteins (TSP). Cd promoted an increase in the concentration of total soluble carbohydrates (TSC), proline, sucrose, and reducing sugars in the plants. The increase in TSC, sucrose and proline, suggests a metabolic regulatory mechanism of V. surinamensis against Cd stress.

关键词： Coconut seedlings   K+/Na(+)ratio   Salinity   Sea level rise   Growth   Photosynthesis  

摘要： Coconut is grown along the coasts and islands that are vulnerable to climate change-induced sea level rise. Though coconut is considered moderately salt tolerant, our understanding on the growth and physiological response to sea water, either inundation or subsurface water contamination, is very limited. This understanding will enable to effectively manage coconut in coastal systems under future climatic scenarios. In this study, ten month old hydroponically grown coconut seedlings were subjected to 0, 10, 25, 50, 75 and 100 % of sea water substitution (SWS), equivalent to 2.17, 8.32, 16.32, 30.03, 42.14 and 53.69 dS m(-1) EC, respectively. Substituting Hoagland solution in hydroponic system by sea water of increasing concentration (>50 % SWS) significantly changed physiological processes;Fv/Fm decreased and r s increased as early as 7 and 18 days after treatment imposition (DAT), respectively which led to significant decline in leaf area and root length expansion as early as 24 DAT. At 25 % SWS, root system (root length and root biomass) was stable but the aerial part biomass was declined by 47 %. On the other hand plant height, leaf area, collar girth and biomass accumulation of seedlings under 10 % SWS (8.32 EC) was on par with the control plants suggesting coconut seedlings could tolerate 10 % SWS. Though, P-N declined by 19 % and 43 % at 10 % and 25 % SWS, respectively and a similar decline in g, without a concomitant change in leaf water potential suggested that root-generated signals regulated the stomatal movement in coconut under salinity. Still the biomass accumulation at 10 % SWS was not affected by decline in PN. Under increasing sea water treatments, most of the Na+ absorbed was compartmentalized in mot and shoot, while leaf had more accumulation of K+, that ensured high K+/Na+ ratio in the leaves which is an important salinity tolerant mechanism observed in coconut. The leaf Cl - content also had strong negative correlation with [P-N] (r=-0.873) and bi

关键词： Helianthus annuus   Cadmium accumulation   EDDS   5-aminolevolinic acid   Synergistic effect  

摘要： This study explored the phytoremediation potential of sunflower on cadmium (Cd) contaminated soils. We also studied the mechanisms through which a plant growth regulator, 5-aminolevolinic acid (ALA) protected sunflower plants from Cd-induced cellular injury. Six-leaf old sunflower plants were exposed to 0.3 g kg(-1) Cd for one week and then treated with chelating agents i.e. trisodium (S,S)-ethylenediamine-N,N'-disuccinic acid (EDDS, 5 mmol kg(-1)) and citric acid (CA,10 mmol kg(-1)), and 10 mg L-1 ALA. One week after chelators and ALA application, plants were harvested for further analyses. Results suggested that chelators EDDS/CA significantly increased Cd accumulation but inhibited plant growth of sunflower. In contrast, ALA promoted both Cd absorption and biomass accumulation, especially when applied in combination with EDDS. Bioaccumulation quantity and remove efficiency of Cd + EDDS + ALA treated plants was increased by 21.00% and 20.93% as compared with Cd + EDDS treatment. The qRT-PCR results revealed that increased Cd uptake by chelators EDDS/CA and ALA was associated with an increased expression of Cd transport genes e.g. OPT6, HMA3 and Nramp1 in sunflower leaves and roots. Our study suggested that ALA protects sunflower plants from Cd-induced cellular injury by immobilizing Cd ions, modulating activities of antioxidative enzymes and capturing reactive oxygen species.

关键词： Kiwifruit   Color diversity   Carotenoid   Gene expression   Yellow flesh  

摘要： To identify the biochemical and molecular factors causing flesh-color variation between two yellow-flesh kiwifruit cultivars 'Jinshi 1' and 'Jinyan', the composition of carotenoids and chlorophyll, and associated gene expression profile in their pulp were investigated during fruit development. At harvest, 'Jinshi 1' exhibited brighter yellow flesh than 'Flort16A' with a lower color hue angle, although they had a similar total carotenoid content. At the molecular level, 'Jinshi 1' exhibited higher expression level of chlorophyll catabolic genes (CBR, PPH, and PAO), leading to lower accumulation of chlorophyll in the flesh. Meanwhile, higher expression levels of NCED1 resulted in greater carotenoid degradation in 'Flort16A' . In addition, 'Flort16A' had a higher content of lutein, zeaxanthin and beta-carotene, whereas 'Jinshi 1' had specific beta-cryptoxanthin on ripening, accordingly, the expression of CHYB1, which encodes the enzyme for the formation of zeaxanthin and beta-cryptoxanthin, was higher during the last developmental stage in 'Jinshi 1' than in 'Flort16A'. These results suggested that the higher carotenoid/chlorophyll ratio, as well as the higher beta-cryptoxanthin proportion are the important reasons for the brighter yellow flesh color.

关键词： 青年论坛   《中国生物化学与分子生物学报》   信息交流   新栏目   特约综述   研究简报   专刊   技术与方法  

摘要： 《中国生物化学与分子生物学报》传统栏目包括综述、研究论文、技术与方法、研究简报、信息交流等。为丰富内容并提高影响力,2015年起期刊陆续推出了特约综述、要文聚焦、青年论坛、术语商榷、教育教学等新栏目,并设立了专刊专栏。

关键词： 微课   临床生物化学   应用  

摘要： 临床生物化学属于基础医学的范畴,与各个学科存在密切的关联,承担着"桥梁"的作用。医学检验专业由5年改为4年,导致教学质量出现严重的偏差,表现如下:(1)课程内容的严重压缩、框架结构不完整;(2)教师和学生都备感教学的压力;(3)学生丧失激发学习的热情。微课程是在新世纪教学改革发展下的"产物"。微课程具有容量小、用时短、传播方式多样化的优点,通过微课程的推广和革新,促进教学改革,提升教学水平。

关键词： 食品工艺学   成果导向理念   教学改革   多元化考核  

摘要： 食品工艺学是食品科学与工程专业一门重要的核心主干课程,在食品专业人才培养中占据重要地位。针对食品工艺学课程教学存在的内容多学时少、教学过程单调、考核方式不能综合评价学生的学习效果等问题,基于成果导向理念,从课程目标确定、教学内容优化、教学模式改革、多元化考核模式构建、教学效果反馈和教学改进等方面,对食品工艺学进行教学改革,以期提高学生学习效果和提升教学质量。通过教学改革前后学生学习效果的比较,发现基于OBE理念的食品工艺学教学改革可提高学生学习效果,增强学生自主学习能力、分析解决问题能力、思维创新能力及解决食品工程实际问题能力。