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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 313: 124102, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38432102

RESUMO

White light-emitting diode (LED) for night lighting disrupts photoperiod in plants, which affects the plant's photosynthesis. Therefore, it is necessary to find a new type of white LED with little effect on plant photosynthesis. In this study, a series of phosphate phosphors Ca9NaY2/3(PO4)7:Dy3+ (CNYP:Dy3+) were synthesized. Cation Li+ substitute Na+ were used to improve the luminescence properties of CNYP:Dy3+ phosphor. The CNYP:Dy3+ phosphor exhibits visible white light emission with emission peaks at 480 nm (blue light) and 570 nm (yellow light) excited by the near ultraviolet light 350 nm. The optimal concentration of Dy3+ was 0.10 mol, and the mechanism of concentration quenching was evaluated as energy migration among the nearest or next-nearest Dy3+. The substitution of Na+ by Li+ of CNYP:0.10Dy3+ improves the internal quantum efficiency from 30.24 % to 59.05 %, and presents good near-zero thermal quenching performance at 423 K. To assess the suitability of this phosphor for urban ecological lighting, the spectrum resemblance (SR) index between the electroluminescence spectrum of the prepared pc-LED and the absorption spectra of chlorophyll a and b was evaluated as 6.63 % and 18.61 %, respectively. This work exhibits a feasible scheme for the development of urban ecological lighting.

2.
Sci Total Environ ; 912: 169048, 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38061654

RESUMO

Biodegradable plastics (BPs) have gained increased attention as a promising solution to plastics pollution problem. However, BPs often exhibited limited in situ biodegradation in the soil environment, so they may also release microplastics (MPs) into soils just like conventional non-degradable plastics. Therefore, it is necessary to evaluate the impacts of biodegradable MPs (BMPs) on soil ecosystem. Here, we explored the effects of biodegradable poly(butylene adipate-co-terephthalate) (PBAT) MPs and conventional polyethylene (PE) MPs on soil-plant (pakchoi) system at three doses (0.02 %, 0.2 %, and 2 %, w/w). Results showed that PBAT MPs reduced plant growth in a dose-dependent pattern, while PE MPs exhibited no significant phytotoxicity. High-dose PBAT MPs negatively affected the rhizosphere soil nutrient availability, e.g., decreased available phosphorus and available potassium. Metagenomics analysis revealed that PBAT MPs caused more serious interference with the rhizosphere microbial community composition and function than PE MPs. In particular, compared with PE MPs, PBAT MPs induced greater changes in functional potential of carbon, nitrogen, phosphorus, and sulfur cycles, which may lead to alterations in soil biogeochemical processes and ecological functions. Moreover, untargeted metabolomics showed that PBAT MPs and PE MPs differentially affect plant root exudates. Mantel tests, correlation analysis, and partial least squares path model analysis showed that changes in plant growth and root exudates were significantly correlated with soil properties and rhizosphere microbiome driven by the MPs-rhizosphere interactions. This work improves our knowledge of how biodegradable and conventional non-degradable MPs affect plant growth and the rhizosphere ecology, highlighting that BMPs might pose greater threat to soil ecosystems than non-degradable MPs.


Assuntos
Plásticos Biodegradáveis , Brassica , Microplásticos , Rizosfera , Ecossistema , Plásticos , Exsudatos e Transudatos , Biodegradação Ambiental , Polietileno , Exsudatos de Plantas , Fósforo , Solo
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 302: 123122, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-37478756

RESUMO

In the natural environment, light is an indispensable factor affecting plant growth, and plant growth phosphor-converted light emitting diodes (pc-LED) for an artificial light source can play a role in accelerating photosynthesis and development of indoor plants. In this work, we obtained a series of red-emitting phosphors Bi3+, Mn4+ co-doped 4SrO‧7Al2O3, which were synthesized by sol-gel method, and red-light emission enhancement through doping of sensitizer Bi3+. The energy transfer process and mechanism were analyzed by photoluminescence spectra and fluorescence lifetime. And it thermal stability was 58.50% at 423 K, which show that the phosphor has good photostability. The red and blue dual emission of the packaged LED device can better match the absorption spectra required by chlorophyll a, b and phytochrome PR of plants. Therefore, the as-prepared phosphor has a certain development prospect in the application of plant growth LEDs.

4.
Front Microbiol ; 14: 1204688, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37333630

RESUMO

Biological seed dressing is a cost-effective means to protect plant roots from pathogens. Trichoderma is generally considered as one of the most common biological seed dressings. However, there is still a dearth of information on the effects of Trichoderma on microbial community of rhizosphere soil. High-throughput sequencing was used to analyze the effects of Trichoderma viride and a chemical fungicide on microbial community of soybean rhizosphere soil. The results showed that both T. viride and chemical fungicide could significantly reduce the disease index of soybean (15.11% for Trichoderma and 17.33% for Chemical), while no significant difference was observed between them. Both T. viride and chemical fungicide could affect the structure of rhizosphere microbial community, they increased the ß-diversity of microbial community and significantly reduce the relative abundance of Saprotroph-Symbiotroph. Chemical fungicide could reduce the complexity and stability of co-occurrence network. However, T. viride is beneficial for maintaining network stability and increasing network complexity. There were 31 bacterial genera and 21 fungal genera significantly correlated with the disease index. Furthermore, several potential plant pathogenic microorganisms were also positively correlated with disease index, such as Fusarium, Aspergillus, Conocybe, Naganishia, and Monocillium. From this work, T. viride may be used as a substitute for chemical fungicide to control soybean root rot and be more friendly to soil microecology.

5.
Int J Syst Evol Microbiol ; 72(10)2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36269580

RESUMO

Four Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and non-motile strains (CAK1WT, CAK8WT, CAK57W and CCL10WT) were isolated from salt lakes in China. Comparisons based on the 16S rRNA gene sequences showed that the four strains show less than 98.9% similarity to species of the genus Psychroflexus. The phylogenetic tree reconstructed based on 16S rRNA gene sequences also showed that Psychroflexus species are the most closely related neighbours of the four strains. The sequenced draft genome sizes of strains CAK1WT, CAK8WT, CAK57W and CCL10WT were 3.01, 2.95, 3.01 and 3.04 Mbp with G+C contents of 37.3, 35.8, 37.5 and 36.6 %, respectively. The phylogenomic trees reconstructed based on the UBCG and GET_PHYLOMARKERS pipelines all demonstrated that the four strains belong to the genus Psychroflexus. The calculated pairwise orthologous average nucleotide identity based on usearch, digital DNA-DNA hybridization and average amino acid sequence identity values among strains CAK1WT, CAK8WT, CAK57W, CCL10WT and other species of the genus Psychroflexus were equal or lower than 91.1, 43.5 and 92.2%; the values between strains CAK1WT and CAK57W were 98.8, 90.2 and 99.0 %, respectively. The respiratory quinone of the four strains was MK-6. Their major fatty acids were iso-C14 : 0, C15 : 1 ω10c, iso-C15 : 0 and anteiso-C15 : 0. The major polar lipids of the four strains included phosphatidylethanolamine, an unidentified aminolipid and two kinds of unidentified lipids, and only strain CCL10WT contained diphosphatidylglycerol. Based on the above descriptions, strains CAK1WT, CAK8WT, CAK57W and CCL10WT should belong to the genus Psychroflexus and represent three independent novel species, for which the names Psychroflexus curvus sp. nov. (type strain CAK1WT=GDMCC 1.2644T=KCTC 82857T), Psychroflexus longus sp. nov. (type strain CAK8WT=GDMCC 1.2646T=KCTC 82859T) and Psychroflexus montanilacus sp. nov. (type strain CCL10WT=GDMCC 1.2631T=KCTC 82860T) are proposed.


Assuntos
Flavobacteriaceae , Lagos , Técnicas de Tipagem Bacteriana , Composição de Bases , Cardiolipinas , Catalase/genética , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae/genética , Flavobacteriaceae/isolamento & purificação , Lagos/microbiologia , Nucleotídeos , Fosfatidiletanolaminas/química , Fosfolipídeos/química , Filogenia , Quinonas , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tibet
6.
J Photochem Photobiol B ; 235: 112564, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36116228

RESUMO

Industrial Seedling Raising (ISR) is increasingly becoming an important part of Modern Agriculture because of its efficient utilization of land, water, and fertilizer as well as its advantages of being not easily affected by the weather. However, the high cost and high energy consumption of light sources for plant growth is limiting the popularization of ISR technology. Phosphor-converted light-emitting diodes (pc-LEDs) make use of relatively affordable red phosphor and blue light chips, providing an adjustable spectrum to optimize plant growth. To identify the energy-saving light quality of pc-LEDs, we investigated the effects of a variety of light qualities on the growth of tobacco seedlings. Y3Al5O12:Ce3+, CaAlSiN3:Eu2+, KAl11O17:Eu2+ phosphors were combined with the blue light chip according to different proportions to produce the following light sources: CK (white light), T1 (blue light), T2 (red light), T3 (red: blue light ratio = 1:4), T4 (red: blue light ratio = 4:1). The tobacco variety Xiangyan7 grown continuously under T1, T2, T3, and T4 significantly increased the leaf area, stem length, biomass, root area and main root length compared with those grown under white light. Among the five kinds of light qualities tested, T4 treatment exerted the best effect on leaf development and biomass increase, while T2 exerted the best effect on stem elongation. The cytological analysis demonstrated that the promotion of the cell size and cell number of leaf epidermal cells by T1-T4 might contribute to the leaf expansion. Further analysis at the molecular level suggested that the light quality affected the RNA levels of the genes involved in cell division and expansion. When tobacco seedlings reached the same biomass, T1-T4 light sources saved 71%, 86%, 80% and 89% of electric energy respectively compared with white light. Therefore, the application of specific pc-LEDs not only reduces the cost of light source production, but also saves energy consumption, offering great potential for ISR technology to cut costs and increase efficiency.


Assuntos
Plântula , Fertilizantes , RNA , Água
7.
Inorg Chem ; 61(33): 13104-13114, 2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-35952657

RESUMO

Recently, Bi3+-activated phosphors have been widely researched for phosphor-converted light-emitting diode (pc-LED) applications. Herein, novel full-spectrum A3BO7:Bi3+ (A = Gd, La; B = Sb, Nb) phosphors with a luminescence-tunable performance were achieved by a chemical substitution strategy. In the La3SbO7 host material, a new luminescent center was introduced, with Gd3+ replacing La3+. The photoluminescence (PL) spectra show a large blue shift from 520 to 445 nm, thus achieving regulation from green to blue lights. Moreover, a series of solid solution-phase phosphors La3Sb1-xNbxO7:Bi3+ were prepared by replacing Sb with Nb, and a PL spectral tunability from green (520 nm) to orange-red (592 nm) was realized. Temperature-dependent PL spectra show that La3-xGdxSbO7:Bi3+ phosphors have excellent thermal stability. Upon 350 nm excitation, the PL intensity of La3-xGdxSbO7:Bi3+ phosphors at 150 °C remained at more than 93% at room temperature. With Gd3+ doping, the thermal stability gradually improved, and LaGd2SbO7:0.03Bi3+ represents splendid antithermal quenching (135.2% at 150 °C). Finally, a full-visible spectrum for pc-LED with a high color-rendering index (Ra = 94.4) was obtained. These results indicated that chemical substitution is an effective strategy to adjust the PL of Bi3+, which is of great significance in white-light illumination and accurate plant lighting.

8.
Artigo em Inglês | MEDLINE | ID: mdl-35076362

RESUMO

Two Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and non-motile strains (LM13ST and JZCK2T) were isolated from hypersaline lakes in China. The colonies of both strains were yellow-pigmented and convex. Both strains could grow at 4-34 °C, pH 6.5-9.0 and with 1.0-13.0 % (w/v) NaCl. Comparisons based on 16S rRNA gene sequences showed that strains LM13ST and JZCK2T share less than 98.3 % similarity with species of the genus Salegentibacter. The phylogenetic tree reconstructed based on 16S rRNA gene sequences also showed that Salegentibacter species are the most closely related neighbours of strains LM13ST and JZCK2T. The sequenced draft genome sizes of strains LM13ST and JZCK2T are 4.06 and 4.22 Mbp with G+C contents of 37.0 and 37.8 mol%, respectively. The phylogenomic tree reconstructed using the Up-to-date Bacterial Core Gene set pipeline also demonstrated that both strains belong to the genus Salegentibacter. The calculated pairwise average nucleotide identity values and digital DNA-DNA hybridization values between strains LM13ST and JZCK2T and Salegentibacter species were less than 86.4 and 32.0 %, respectively. The respiratory quinone in both strains was MK-6. Their major fatty acids were iso-C12 : 0, iso-C14 : 0, C15 : 1 ω10c, iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C17 : 1 ω10c. Their major polar lipids included phosphatidylethanolamine, one unidentified lipid and one unidentified aminolipid, but strain LM13ST also contained one more unidentified aminolipid, one more unidentified lipid and one unidentified phospholipid. Combining the above descriptions, strains LM13ST and JZCK2T should represent two independent novel species of the genus Salegentibacter, for which the names Salegentibacter lacus sp. nov. (type strain LM13ST=GDMCC 1.2643T=KCTC 82861T) and Salegentibacter tibetensis sp. nov. (type strain JZCK2T=GDMCC 1.2621T=KCTC 82862T) are proposed.


Assuntos
Ácidos Graxos , Flavobacteriaceae/classificação , Lagos , Filogenia , Águas Salinas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Flavobacteriaceae/isolamento & purificação , Lagos/microbiologia , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tibet
9.
Int J Syst Evol Microbiol ; 72(12)2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36748472

RESUMO

Thousands of lakes harbouring different characteristics (pH, salinity, temperature) are located on the Tibetan Plateau, and the mining of microbial resources inhabited in these lakes has great value. Two Gram-stain-negative, aerobic, rod-shaped, non-motile strains (LQ15WT and AIY15WT) were isolated from freshwater lakes on the Tibetan Plateau. Comparisons based on the 16S rRNA gene sequences showed that both strains LQ15WT and AIY15WT share 16S rRNA gene sequence similarities 98.4 % with Aquiflexum aquatile Z0201T, but only about 95.0 % with Aquiflexum balticum DSM 16537T. The 16S rRNA gene sequence similarity between strains LQ15WT and AIY15WT was 98.9 %. The phylogenetic tree reconstructed based on 16S rRNA gene sequences also showed that strains LQ15WT and AIY15WT take A. aquatile Z0201T as their closest neighbour and these three strains form a tight cluster. In the phylogenomic tree, the genus Aquiflexum was splited into two clusters by Mariniradius saccharolyticus. Strains LQ15WT, AIY15WT and A. aquatile Z0201T still formed a close cluster, and A. balticum DSM 16537T and Aquiflexum lacus CUG 91378T formed another cluster. The calculated OrthoANIu, average amino acid identity and digital DNA-DNA hybridization values among strains LQ15WT, AIY15WT, A. aquatile Z0201T, A. balticum DSM 16537T and A. lacus CUG 91378T were less than 91.0, 92.9 and 42.1 %, respectively. The major respiratory quinones of both strains LQ15WT and AIY15WT were MK-7 (32 %) and MK-8 (68 %), and their major fatty acids were iso-C15 : 0, C18 : 1 ω9c, summed feature 3 and summed feature 9. The predominant polar lipids of both strains were phosphatidylethanolamine, unidentified aminophospholipids, unidentified phospholipids and lipids. Strain AIY15WT also contained phosphatidylglycerol and unidentified glycolipid. Considering the distinct phylogenetic relationships and chemotaxonomic characteristics between strains A. aquatile Z0201T and A. balticum DSM 16537T, it is proposed to reclassify A. aquatile into a novel genus Cognataquiflexum gen. nov. as Cognataquiflexum aquatile comb. nov., and strains LQ15WT and AIY15WT should represent two independent novel species of the genus Cognataquiflexum, for which the names Cognataquiflexum nitidum sp. nov. (type strain: LQ15WT=CICC 24711T=JCM 34222T) and Cognataquiflexum rubidum sp. nov. (type strain: AIY15WT=CICC 24708T=JCM 34612T) are proposed.


Assuntos
Ácidos Graxos , Lagos , Ácidos Graxos/química , Tibet , Filogenia , RNA Ribossômico 16S/genética , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Análise de Sequência de DNA , Composição de Bases , Fosfolipídeos/química
10.
Microorganisms ; 9(8)2021 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-34442656

RESUMO

The genus Methylophilus uses methanol as a carbon and energy source, which is widely distributed in terrestrial, freshwater and marine ecosystems. Here, three strains (13, 14 and QUAN) related to the genus Methylophilus, were newly isolated from Lake Fuxian sediments. The draft genomes of strains 13, 14 and QUAN were 3.11 Mb, 3.02 Mb, 3.15 Mb with a G+C content of 51.13, 50.48 and 50.33%, respectively. ANI values between strains 13 and 14, 13 and QUAN, and 14 and QUAN were 81.09, 81.06 and 91.46%, respectively. Pan-genome and core-genome included 3994 and 1559 genes across 18 Methylophilus genomes, respectively. Phylogenetic analysis based on 1035 single-copy genes and 16S rRNA genes revealed two clades, one containing strains isolated from aquatic and the other from the leaf surface. Twenty-three aquatic-specific genes, such as 2OG/Fe(II) oxygenase and diguanylate cyclase, reflected the strategy to survive in oxygen-limited water and sediment. Accordingly, 159 genes were identified specific to leaf association. Besides niche separation, Methylophilus could utilize the combination of ANRA and DNRA to convert nitrate to ammonia and reduce sulfate to sulfur according to the complete sulfur metabolic pathway. Genes encoding the cytochrome c protein and riboflavin were detected in Methylophilus genomes, which directly or indirectly participate in electron transfer.

11.
Materials (Basel) ; 14(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806635

RESUMO

Pipelines work in serious vibration environments caused by mechanical-based excitation, and it is thus challenging to put forward effective methods to reduce the vibration of pipelines. The common vibration control technique mainly uses the installation of dampers, constrained layer damping materials, and an optimized layout to control the vibration of pipelines. However, the passive damping treatment has little influence on the low frequency range of a pipeline system. Active control technology can obtain a remarkable damping effect. An active constrained layer damping (ACLD) system with piezoelectric materials is proposed in this paper. This paper aims to investigate the vibration and damping effect of ACLD pipeline under fixed support. The finite element method is employed to establish the motion equations of the ACLD pipeline. The effect of the thickness and elastic modulus of the viscoelastic layer, the laying position, and the coverage of ACLD patch, and the voltage of the piezoelectric material are all considered. The results show that the best damping performance can be obtained by selecting appropriate control parameters, and it can provide effective design guidance for active vibration control of a pipeline system.

12.
Int J Syst Evol Microbiol ; 70(10): 5217-5225, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32816656

RESUMO

Two novel Gram-stain-negative, aerobic and non-motile rods bacteria, designated TQ8ST and ZH2ST, were isolated from salt marsh sediment collected from the Tibetan Plateau. Strain TQ8ST was found to grow at 10-40 °C (optimum, 30 °C), pH 6.0-11.0 (optimum, pH 8.0-9.0) and in the presence of 2-12 % (w/v) NaCl (optimum, 6-8 %). Strain ZH2ST was found to grow at 15-40 °C (optimum, 30 °C), pH 7.0-10.0 (optimum pH 9.0) and in the presence of 2-10 % (w/v) NaCl (optimum, 4-6 %). Phylogenetic analysis based on the 16S rRNA gene sequences showed that strains TQ8ST and ZH2ST shared 99.07 % sequence similarity between each other and were affiliated with the genus Halomonas, sharing 97.48 % and 97.41 % of sequence similarity to their closest neighbour Halomonas sulfidaeris Esulfide1T, respectively. DNA-DNA hybridization analyses showed 61.0 % relatedness between strains TQ8ST and ZH2ST. The average nucleotide identity and the average amino acid identity values between the two genomes were 92.33 and 92.84 %, respectively. The values between the two strains and their close phylogenetic relatives were all below 95 %. The major respiratory quinones of strain TQ8ST were Q-9 and Q-8, while that of ZH2ST was Q-9. The main fatty acids shared by the two strains were C18 : 1 ω6c and/or C18 : 1 ω7c, C16 : 1 ω6c and/or C16 : 1 ω7c, C16 : 0 and C12 : 0 3-OH. Strain ZH2ST can be distinguished from TQ8ST by a higher proportion of C19 : 0 cyclo ω8c. The G+C content of the genomic DNA of strains TQ8ST and ZH2ST were 57.20 and 57.14 mol%, respectively. On the basis of phenotypic distinctiveness and phylogenetic divergence, the two isolates are considered to represent two novel species of the genus Halomonas, for which the names Halomonas rituensis sp. nov (type strain TQ8ST=KCTC 62530T=CICC 24572T) and Halomonas zhuhanensis sp. nov (type strain ZH2ST=KCTC 62531T=CICC 24505T) are proposed.


Assuntos
Sedimentos Geológicos/microbiologia , Halomonas/classificação , Filogenia , Áreas Alagadas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Halomonas/isolamento & purificação , Hibridização de Ácido Nucleico , Quinonas/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tibet
13.
Materials (Basel) ; 13(4)2020 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-32102288

RESUMO

In order to enhance the mechanical property of auxetic lattice structures, a new enhanced auxetic lattice structure was designed by embedding narrow struts into a three-dimensional (3D) re-entrant lattice structure. A series of enhanced lattice structures with varied parameters were fabricated by 3D printing combined with the molten metal infiltration technique. Based on the method, parameter studies were performed. The enhanced auxetic lattice structure was found to exhibit superior mechanical behaviors compared to the 3D re-entrant lattice structure. An interesting phenomenon showed that increasing the diameter of connecting struts led to less auxetic and non-auxetic structures. Moreover, the compressive property of the enhanced structure also exhibited obvious dependence on the base material and compression directions. The present study can provide useful information for the design, fabrication and application of new auxetic structures with enhanced properties.

14.
Int J Biol Macromol ; 109: 880-887, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29155203

RESUMO

CsnA, a chitosanase from Renibacterium sp. QD1, has great potential for industrial applications due to its high yield and broad pH stability. In this study, a specific Glu160 in CsnA was identified by sequence alignment, and structural analysis and MD simulation predicted that Glu160 formed a hydrogen-bond network with Lys163 and Thr114. To evaluate the effect of the network, we constructed four mutants, including E160A, E160Q, K163A, and T114A, which partially or completely destroy this network. Characterization of these mutants demonstrated that the disruption of the network significantly decreased the enzyme thermostability. The underlying mechanisms responsible for the change of thermostability analyzed by circular dichroism spectroscopy revealed that the hydrogen-bond network conferred the structural stability of CsnA. Moreover, the length of the side chain of residue at 160 impacted conformational stability of the enzyme. Taken together, the hydrogen-bond network around Glu160 plays important roles in stabilization of CsnA.


Assuntos
Actinobacteria/enzimologia , Ácido Glutâmico/química , Glicosídeo Hidrolases/química , Ligação de Hidrogênio , Actinobacteria/genética , Sequência de Aminoácidos , Varredura Diferencial de Calorimetria , Dicroísmo Circular , Ativação Enzimática , Estabilidade Enzimática , Expressão Gênica , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Modelos Moleculares , Estrutura Molecular , Mutação , Conformação Proteica
15.
Biotechnol Lett ; 40(1): 83, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29209892

RESUMO

In Table 1 as published, some of the data were wrong. The corrected Table 1 is shown below.

16.
Biotechnol Lett ; 40(1): 225-226, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29204768

RESUMO

In Table 1 as published, some of the data were wrong. The corrected Table 1 is shown here. In addition, according to the corrected Table 1, the sentence "the k cat /K m of CsnA-CBM5 was higher than that of WT by 143%" in the part of "The kinetic parameters and specific activity" in the Results part should be changed to "the k cat /K m of CsnA-CBM5 was higher than that of WT by 110%".

17.
Biotechnol Lett ; 40(1): 75-82, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28905142

RESUMO

OBJECTIVE: To determine the effects of the extra N-terminal seven-amino-acid sequence on the function of chitosanase CsnA. RESULTS: Sequence and structure analysis indicated that the mature CsnA contains a seven-amino-acid extension in a disordered form at the N-terminus. To determine the function of this sequence, both mature CsnA and its N-terminus-truncated mutant, CsnAΔN, were expressed in Escherichia coli and characterized. Compared with CsnAΔN, CsnA exhibited a 15 °C higher temperature optimum, enhanced pH stability, thermostability and catalytic efficiency. The underlying mechanisms responsible for these changes were analyzed by circular dichroism (CD) spectroscopy. CD analysis revealed that the deletion of the N-terminal sequence resulted in a decrease in the Tm of 4.3 °C and this sequence altered the secondary structure of the enzyme. CONCLUSIONS: The N-terminal sequence is essential for the stability and activity of chitosanase CsnA.


Assuntos
Estabilidade Enzimática , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Dicroísmo Circular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Glicosídeo Hidrolases/genética , Concentração de Íons de Hidrogênio , Proteínas Recombinantes/genética , Deleção de Sequência , Temperatura
18.
Biotechnol Lett ; 39(12): 1895-1901, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28748352

RESUMO

OBJECTIVE: To determine the effects of carbohydrate-binding modules (CBMs) on the thermostability and catalytic efficiency of chitosanase CsnA. RESULTS: Three CBMs (BgCBM5, PfCBM32-2 and AoCBM35) were engineered at the C-terminus of chitosanase CsnA to create hybrid enzymes CsnA-CBM5, CsnA-CBM32 and CsnA-CBM35. K m values of all the hybrid enzymes were lower than that of the wild type (WT) enzyme; however, only CsnA-CBM5 had an elevated specific activity and catalytic efficiency. The fusion of BgCBM5 enhanced the thermostability of the enzyme, which exhibited a 8.9 °C higher T50 and a 2.9 °C higher Tm than the WT. Secondary structural analysis indicated that appending BgCBM5 at the C-terminus considerably changed the secondary structure content. CONCLUSIONS: The fusion of BgCBM5 improved the thermal stability of CsnA, and the obtained hybrid enzyme (CsnA-CBM5) is a useful candidate for industrial application.


Assuntos
Proteínas de Bactérias , Glicosídeo Hidrolases , Engenharia de Proteínas/métodos , Proteínas Recombinantes de Fusão , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Estabilidade Enzimática , Escherichia coli/genética , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Ligação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Temperatura
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