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1.
Int Orthop ; 48(2): 481-486, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37725151

RESUMO

PURPOSE: This is a retrospective study and aims to investigate the clinical outcomes of patients with knee varus deformity and extruded medial meniscus who underwent arthroscopic meniscus centralization and medial opening wedge high tibial osteotomy. METHODS: A total of 24 patients were included in the trial, and arthroscopy intraoperative photographs and standing preoperative and postoperative radiographs were taken to analyze the mechanical tibiofemoral angle and tibial plateau inclination. Postoperative complications and knee motion were recorded, and the surgical results were evaluated using the knee society score. RESULTS: The study observed four cases of surgery-related complications among all patients, but no major complications were reported. The surgery significantly improved knee flexion degrees and total knee range of motion. Satisfactory outcomes were shown in postoperative radiographs and secondary intraoperative photographs. The knee score increased from 39.6 ± 10.0 to 80.1 ± 9.0, and the functional score improved from 48.1 ± 6.9 to 89.4 ± 5.5. The preoperative tibial plateau inclination was 5.3 ± 0.7, while the postoperative data showed a decrease to 4.2 ± 0.7. The preoperative mechanical tibiofemoral angle was - 7.7 ± 1.0, and it improved in all patients postoperatively to 2.8 ± 0.9. CONCLUSION: By alternating the knee biomechanics and significantly improving symptoms and quality of life, arthroscopic medial meniscus centralization and medial open wedge high tibial osteotomy units are confirmed to be an effective alternative treatment for knee varus deformity.


Assuntos
Meniscos Tibiais , Osteoartrite do Joelho , Humanos , Meniscos Tibiais/diagnóstico por imagem , Meniscos Tibiais/cirurgia , Seguimentos , Estudos Retrospectivos , Qualidade de Vida , Osteoartrite do Joelho/cirurgia , Osteoartrite do Joelho/etiologia , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Tíbia/diagnóstico por imagem , Tíbia/cirurgia , Osteotomia/efeitos adversos , Osteotomia/métodos
2.
Chembiochem ; 19(19): 2049-2054, 2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30025196

RESUMO

Baeyer-Villiger monooxygenases (BVMOs) are versatile biocatalysts in organic synthesis that can generate esters or lactones by inserting a single oxygen atom adjacent to a carbonyl moiety. The regioselectivity of BVMOs is essential in determining the ratio of two regioisomers for converting asymmetric ketones. Herein, we report a novel BVMO from Pseudomonas aeruginosa (PaBVMO); this has been exploited for the direct synthesis of medium-chain α,ω-dicarboxylic acids through a Baeyer-Villiger oxidation-hydrolysis cascade. PaBVMO displayed the highest abnormal regioselectivity toward a variety of long-chain aliphatic keto acids (C16 -C20 ) to date, affording dicarboxylic monoesters with a ratio of up to 95 %. Upon chemical hydrolysis, α,ω-dicarboxylic acids and fatty alcohols are readily obtained without further treatment; this significantly reduces the synthetic steps of α,ω-dicarboxylic acids from renewable oils and fats.


Assuntos
Ácidos Carboxílicos/metabolismo , Oxigenases de Função Mista , Pseudomonas aeruginosa/metabolismo , Biocatálise , Ácidos Dicarboxílicos/metabolismo , Ésteres/metabolismo , Hidrólise , Isomerismo , Cetoácidos/metabolismo , Cetonas/metabolismo , Lactonas/metabolismo , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Oxirredução , Especificidade por Substrato
3.
Biotechnol Bioeng ; 113(11): 2350-7, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27216910

RESUMO

Malathion is one of the most widely used organophosphorus pesticides in the United States and developing countries. Herein, we enhanced the degradation rate of malathion starting with a phosphotriesterase PoOPHM2 while also considering thermostability. In the first step, iterative saturation mutagenesis at residues lining the binding pocket (CASTing) was employed to optimize the enzyme active site for substrate binding and activity. Hot spots for enhancing activity were then discovered through epPCR-based random mutagenesis, and these beneficial mutations were then recombined by DNA shuffling. Finally, guided by in silico energy calculations (FoldX), thermostability of the variant was improved. The mutations extend from the core region to the enzyme surface during the evolutionary pathway. After screening <9,000 mutants, the best variant PoOPHM9 showed 25-fold higher activity than wild-type PoOPHM2 , with a thermostability (T50 (15) ) of 67.6°C. Thus, PoOPHM9 appears to be an efficient and robust candidate for malathion detoxification. Biotechnol. Bioeng. 2016;113: 2350-2357. © 2016 Wiley Periodicals, Inc.


Assuntos
Evolução Molecular Direcionada/métodos , Malation/química , Simulação de Acoplamento Molecular/métodos , Mutagênese Sítio-Dirigida/métodos , Hidrolases de Triester Fosfórico/química , Hidrolases de Triester Fosfórico/genética , Sítios de Ligação , Biodegradação Ambiental , Técnicas de Química Combinatória/métodos , Ativação Enzimática/genética , Ligação Proteica , Engenharia de Proteínas/métodos , Relação Estrutura-Atividade
4.
Appl Microbiol Biotechnol ; 99(4): 1701-8, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25104035

RESUMO

Bacillus amyloliquefaciens esterase (BAE) was applied to produce (R)-1-(3',4'-methylenedioxyphenyl)ethanol, a chiral drug intermediate. In this study, we improved the enantioselectivity of BAE by protein engineering instead of process engineering as used in our previous work. Saturation mutagenesis was carried out on eight positions of BAE based on structure modeling and substrate docking. A double substituted variant V10 (K358D/A396C) showed an excellent enantioselectivity without decreasing the activity. The functions of these two mutations (K358D and A396C) were investigated, revealing a synergic effect on the BAE enantioselectivity. Using the variant V10, enantiopure (R)-1-(3',4'-methylenedioxyphenyl)ethanol could be readily prepared in >97 % ee, affording a high space-time yield (123 g L(-1) day(-1)) and a high ratio of substrate/catalyst (40 g g(-1)) in 1-L reaction.


Assuntos
Acetatos/metabolismo , Bacillus/enzimologia , Esterases/metabolismo , Estereoisomerismo , Bacillus/genética , Análise Mutacional de DNA , Esterases/genética , Mutagênese , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Engenharia de Proteínas , Especificidade por Substrato
5.
J Multidiscip Healthc ; 17: 573-583, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38343756

RESUMO

Purpose: This study aims to explore the factors linked to the occurrence of acute pulmonary thromboembolism (PE) within a cohort of patients exhibiting hypoxic saturation (oxygen saturation levels falling below 93%), subsequent to undergoing off-pump coronary artery bypass grafting (OPCABG). Methods: A retrospective case-control study was conducted. A total of 296 patients met the inclusion and exclusion criteria, divided into PE group (100 cases) and non-PE group (196 cases) according to whether they had PE or not. The preoperative and postoperative information of patients were collected and statistically analyzed. Results: The results from a multivariate logistic regression analysis indicated the following factors were independently linked to PE following OPCABG: history of smoking (OR = 3.019, 95% CI, 1.437-6.634, P = 0.004), preoperative arterial oxygen partial pressure ≤78.9 mmHg (OR = 3.686, 95% CI, 1.708-8.220, P = 0.001), presence of postoperative lower extremity deep venous thrombosis (OR = 4.125, 95% CI, 1.886-9.310, P < 0.001), elevated postoperative D-dimer levels >6.76 mg/l (OR = 8.078, 95% CI, 3.749-18.217, P<0.001), postoperative NT-BNP levels (OR = 1.001, 95% CI: 1.000-1.001, P = 0.011), and elevated postoperative pulmonary arterial pressure >33.0 mmHg (OR = 10.743, 95% CI: 3.422-37.203, P < 0.001). The developed nomogram exhibited a high predictive accuracy with an area under the curve of 0.913 (95% CI: 0.878-0.948). Conclusion: When patients have a history of preoperative smoking, decreased preoperative arterial oxygen pressure, postoperative lower limb DVT, increased postoperative pulmonary artery pressure, and elevated postoperative D-Dimer and NT pro-BNP levels, it is recommended to take perioperative preventive measures, timely diagnostic evaluation, and if necessary, anticoagulant treatment. In addition, the results of this study may improve the diagnostic sensitivity of medical staff for postoperative PE in OPCABG, thereby increasing the detection rate and potentially reducing the need for excessive medical imaging procedures.

6.
World J Clin Cases ; 11(19): 4698-4706, 2023 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-37469734

RESUMO

BACKGROUND: Subcutaneous emphysema is a well-known complication of oral surgery, especially during mandibular wisdom tooth extraction. However, subcutaneous emphysema secondary to dental procedures such as crown preparation is rare. The main symptom of emphysema is swelling and crepitus on palpation. Uncontrolled emphysema may spread along the fascial planes and cause deep space infections or a pneumomediastinum. CASE SUMMARY: In this paper, we report a 34-year-old female who underwent upper molar tooth preparation for crowns and subsequently developed extensive subcutaneous emphysema on the retromandibular angle on two different occasions. The treatment plan for this patient involved close observation of the airway, and administration of dexamethasone and antibiotics via intravenous drip or orally. Ice bag compression was quickly applied and medication was prescribed to alleviate discomfort and promote healing. Although the main reason is unclear, the presence of a fissure in the molar is an important clue which may contribute to the development of subcutaneous emphysema during crown preparation. It is imperative for dental professionals to recognize such pre-disposing factors in order to minimize the risk of complications. CONCLUSION: This case highlights the need for prompt diagnosis and management of subcutaneous emphysema because of the risk of much more serious complications. Awareness of relatively "benign" subcutaneous emphysema during any dental procedure is critical not only for inexperienced dentists, but also for those who work in rural and remote settings as members of surgical teams. In this study, we review the clinical presentation, mechanism, and differential diagnosis of subcutaneous emphysema.

7.
Rapid Commun Mass Spectrom ; 25(23): 3504-8, 2011 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-22095498

RESUMO

The gas-phase studies of transition-metal oxides continue to attract interest as such oxides are being used as catalysts in various oxidation processes. In this paper, singly negatively charged heteropolyoxotungstate and isopolyoxotungstate ion clusters were produced from Keggin-type polyoxotungstates by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS). It was found that the ion series [(PO(3))(WO(3))(n)](-), [(WO(3))(n)](-) and [(OH)(WO(3))(n)](-) were the main fragment ions in the mass spectra and the matrix greatly influenced the resulting cluster ion abundances. [(PO(3))(WO(3))(3)](-), [(WO(3))(3)](-) and [(OH)(WO(3))(4)](-) were the most intense ions in each series when 2-(4-hydroxyphenylazo)benzoic acid was the matrix, whereas [(PO(3))(WO(3))(4)](-), [(WO(3))(6)](-) and [(OH)(WO(3))(4)](-) were the most intense when dithranol (DIT) was the matrix. In addition, a new kind of hybrid ion [W(2)C(14)H(7)O(8)](-) was produced through the reaction of DIT and [(OH)(WO(3))](-) in the plume of the gas phase. These results highlight the utility of the MALDI-FT method for obtaining novel ion clusters and also show the stability of these clusters.


Assuntos
Polímeros/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Compostos de Tungstênio/química , Gases/química , Íons/química
8.
Chem Commun (Camb) ; 57(81): 10584-10587, 2021 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-34559867

RESUMO

A carbonyl reductase variant, SmCRM5, from Serratia marcescens was obtained through structure-guided directed evolution. The variant showed improved specific activity (U mg-1) towards most of the 16 tested substrates and gave high stereoselectivities of up to 99% in the asymmetric synthesis of 13 γ-/δ-lactones. In particular, SmCRM5 showed a 13.8-fold higher specific activity towards the model substrate, i.e., 5-oxodecanoic acid, and gave (R)-δ-decalactone in 99% ee with a space-time yield (STY) of 301 g L-1 d-1. The preparative synthesis of six δ-lactones in high yields and with high enantiopurities showed the feasibility of the biocatalytic synthesis of these high-value-added chemicals, providing a cost-effective and green alternative to noble-metal catalysis.


Assuntos
Oxirredutases do Álcool/metabolismo , Lactonas/metabolismo , Engenharia de Proteínas , Cinética , Lactonas/química , Modelos Moleculares , Estrutura Molecular
9.
Appl Biochem Biotechnol ; 193(8): 2534-2546, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33783700

RESUMO

Due to their unique properties, paper-based biosensors have attracted attention as inexpensive devices for on-site analysis. To achieve fast and sensitive detection of analytes, immobilization of enzymes with high apparent activities on paper is highly desirable; however, this is challenging. Herein, we report an improved approach to attach a malathion degrading enzyme, PoOPHM9, on paper via an interlocking network of Pluronic F127 (PF127)-poly(acrylic acid)-enzyme conjugates. The addition of PF127 improved retention of enzymatic activity as the apparent kinetic constant Vmax of the immobilized enzyme increased two-fold compared with the paper prepared without PF127. The PF127-poly(acrylic acid)-PoOPHM9 papers provided rapid colorimetric detection of malathion at 0.1-50 mM. The detection was completed within 5 min using a smartphone and image analysis software. As a proof-of-concept, malathion-contaminated water, plant, and apple samples were analyzed with the papers successfully. This material is promising for on-site rapid analysis of malathion-contaminated samples.


Assuntos
Técnicas Biossensoriais , Enzimas Imobilizadas/química , Hidrolases/química , Malation/análise , Papel , Colorimetria , Poloxâmero/química
10.
Artigo em Inglês | MEDLINE | ID: mdl-32140463

RESUMO

Metabolic regulation of gene expression for the microbial production of fine chemicals, such as organic acids, is an important research topic in post-genomic metabolic engineering. In particular, the ability of transcription factors (TFs) to respond precisely in time and space to various small molecules, signals and stimuli from the internal and external environment is essential for metabolic pathway engineering and strain development. As a key component, TFs are used to construct many biosensors in vivo using synthetic biology methods, which can be used to monitor the concentration of intracellular metabolites in organic acid production that would otherwise remain "invisible" within the intracellular environment. TF-based biosensors also provide a high-throughput screening method for rapid strain evolution. Furthermore, TFs are important global regulators that control the expression levels of key enzymes in organic acid biosynthesis pathways, therefore determining the outcome of metabolic networks. Here we review recent advances in TF identification, engineering, and applications for metabolic engineering, with an emphasis on metabolite monitoring and high-throughput strain evolution for the organic acid bioproduction.

11.
J Int Med Res ; 48(11): 300060520969331, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33259239

RESUMO

BACKGROUND: Vein graft restenosis (VGR), which appears to be caused by dyslipidemia following vascular transplantation, seriously affects the prognosis and long-term quality of life of patients. METHODS: This study analyzed the genetic data of restenosis (VGR group) and non-stenosis (control group) vessels from patients with coronary heart disease post-vascular transplantation and identified hub genes that might be responsible for its occurrence. GSE110398 was downloaded from the Gene Expression Omnibus database. A repeatability test for the GSE110398 dataset was performed using R language. This included the identification of differentially expressed genes (DEGs), enrichment analysis via Metascape software, pathway enrichment analysis, and construction of a protein-protein interaction network and a hub gene network. RESULTS: Twenty-four DEGs were identified between VGR and control groups. The four most important hub genes (KIR6.1, PCLP1, EDNRB, and BPI) were identified, and Pearson's correlation coefficient showed that KIR6.1 and BPI were significantly correlated with VGR. KIR6.1 could also sensitively predict VGR (0.9 < area under the curve ≤1). CONCLUSION: BPI and KIR6.1 were differentially expressed in vessels with and without stenosis after vascular transplantation, suggesting that these genes or their encoded proteins may be involved in the occurrence of VGR.


Assuntos
Biologia Computacional , Qualidade de Vida , Constrição Patológica , Redes Reguladoras de Genes , Humanos , Mapas de Interação de Proteínas
12.
Front Oncol ; 9: 5, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30723700

RESUMO

Background: Epidemiological evidences regarding the association between physical activity and the risk of lung cancer are still controversial. Objectives: We aimed to investigate the relationship between physical activity and risk of lung cancer in men and women, as well as other high-risk populations such as cigarette smokers. Methods: We conducted a meta-analysis of cohort studies to evaluate the association between physical activity and risk of lung cancer. Relevant studies were identified by searching PubMed and Web of Knowledge through August 2018. Study-specific relative risk (RR) with 95% confidence interval (CI) were pooled using random effect model when significant heterogeneity was detected. Results:Twenty cohort studies with a total of 2,965,811 participants and 31,807 lung cancer cases were included. There was an inverse association between the physical activity and risk of lung cancer. Compared with the low level of physical activity, the pooled RR was 0.83 (95%CI: 0.77, 0.90), with significant heterogeneity (I 2 = 62.6%, P heterogeneity < 0.001). The corresponding pooled RRs were 0.90 (95%CI: 0.82, 0.99) for women and 0.81 (95%CI: 0.73, 0.90) for men. Smokers with a high level of physical activity were associated with a 10% lower risk for lung cancer (RR = 0.90, 95% CI: 0.84, 0.97), while the association was not significant among non-smokers (RR = 0.95, 95% CI: 0.88, 1.03). Subgroups analysis stratified by whether the studies adjusted for smoking intensity and durations yielded the same magnitude of RR. However, the RR for subgroups without adjustment for dietary factors was 0.74 (95%CI: 0.71, 0.77), which was significantly lower than that with dietary factors adjusted (RR = 0.89, 95%CI: 0.84, 0.95). Conclusions:Increased physical activity might be associated with lower risk of lung cancer. Such inverse association was identified among smokers rather than non-smokers. Large interventional studies are expected to further verify these findings.

13.
J Cancer ; 10(9): 2047-2056, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31205565

RESUMO

The evidence of current epidemiological studies investigating the relationship between preoperative anemia and progression of lung cancer (LC) patients remains controversial. The PubMed, EMBASE, and Web of Science databases were comprehensively searched by two independent authors to identify related epidemiological studies from inception through January 31, 2019. Similarly, two researchers separately extracted data and any differences were resolved by discussion. Summarized hazard ratios (HRs) and 95% confidence intervals (CIs) were summarized with inverse variance weighted random effects meta-analysis. Heterogeneity among studies was assessed with the I² statistic. Twenty-two studies were included in this meta-analysis. As compared with LC patients without anemia, those with pre-operative anemia were at a 1.6-fold greater risk of death (summarized HR = 1.58; 95% CI = 1.44-1.75), with moderate heterogeneity (I 2 = 53.1%). Funnel plot and statistical analyses showed no evidence of publication bias. Associations between pre-operative anemia and OS were broadly consistent across numerous subgroups analyses stratified by the study design, geographic location, number of cases, tumor, node, and metastasis (TNM) stage, histology, quality, and adjustment for potential confounders (age, sex, body mass index, TNM stage, histology, performance status, surgery, blood transfusion, and systemic inflammatory response markers). Similar patterns were observed in the sensitivity analyses. The results of meta-regression analysis suggested no evidence of significant heterogeneity between subgroups. In conclusion, pre-operative anemia was associated with poorer overall survival among LC patients.

14.
J Agric Food Chem ; 67(31): 8548-8558, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31266305

RESUMO

Herein, we report a double enzyme system to degrade 12 phthalate esters (PAEs), particularly bulky PAEs, such as the widely used bis(2-ethylhexyl) phthalate (DEHP), in a one-pot cascade process. A PAE-degrading bacterium, Gordonia sp. strain 5F, was isolated from soil polluted with plastic waste. From this strain, a novel esterase (GoEst15) and a mono(2-ethylhexyl) phthalate hydrolase (GoEstM1) were identified by homology-based cloning. GoEst15 showed broad substrate specificity, hydrolyzing DEHP and 10 other PAEs to monoalkyl phthalates, which were further degraded by GoEstM1 to phthalic acid. GoEst15 and GoEstM1 were heterologously coexpressed in Escherichia coli BL21 (DE3), which could then completely degrade 12 PAEs (5 mM), within 1 and 24 h for small and bulky substrates, respectively. To our knowledge, GoEst15 is the first DEHP hydrolase with a known protein sequence, which will enable protein engineering to enhance its catalytic performance in the future.


Assuntos
Proteínas de Bactérias/química , Esterases/química , Ésteres/química , Bactéria Gordonia/enzimologia , Ácidos Ftálicos/química , Sequência de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biocatálise , Biodegradação Ambiental , Dietilexilftalato/química , Dietilexilftalato/metabolismo , Esterases/genética , Esterases/metabolismo , Ésteres/metabolismo , Bactéria Gordonia/genética , Bactéria Gordonia/isolamento & purificação , Bactéria Gordonia/metabolismo , Hidrólise , Ácidos Ftálicos/metabolismo , Alinhamento de Sequência , Microbiologia do Solo
15.
Bioresour Technol ; 262: 177-183, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29705609

RESUMO

Upgrading of biomass-derived 5-hydroxymethylfurfural (HMF) has attracted considerable interest recently. In this work, efficient synthesis of 2,5-bis(hydroxymethyl)furan (BHMF) from HMF was reported with the acclimatized Meyerozyma guilliermondii SC1103 cells entrapped in calcium alginate beads. Catalytic activities of the cells as well as their HMF-tolerant level increased significantly upon acclimatization and immobilization. BHMF was obtained within 7-24 h with good yields (82-85%) and excellent selectivities (99%) when the substrate concentrations were 200-300 mM. In scale-up synthesis, BHMF of up to 181 mM was produced within 7 h, and its productivity was approximately 3.3 g/L h. In addition, the immobilized biocatalyst showed satisfactory operational stability; the cell viability of 70% was retained after reuse 4 times. With rice straw hydrolysate as co-substrate, both the reaction rate and selectivity decreased, likely due to the deleterious influence of xylose in the hydrolysate.


Assuntos
Alginatos , Furanos/química , Furaldeído/análogos & derivados , Ácido Glucurônico , Ácidos Hexurônicos
17.
J Agric Food Chem ; 65(41): 9094-9100, 2017 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-28949531

RESUMO

The biodegradation of pesticides by organophosphorus hydrolases (OPHs) requires an efficient enzyme production technology in industry. Herein, a Pichia pastoris strain was constructed for the extracellular expression of PoOPHM9, an engineered malathion-degrading enzyme. After optimization, the maximum titer and yield of fermentation reached 50.8 kU/L and 4.1 gprotein/L after 3 days, with the highest space-time yield (STY) reported so far, 640 U L-1 h-1. PoOPHM9 displayed its high activity and stability in the presence of 0.1% (w/w) plant-derived detergent. Only 0.04 mg/mL enzyme could completely remove 0.15 mM malathion in aqueous solution within 20 min. Furthermore, 12 µmol malathion on apples and cucumbers surfaces was completely removed by 0.05 mg/mL PoOPHM9 in tap water after 35 min washing. The efficient production of the highly active PoOPHM9 has cleared a major barrier to biodegradation of pesticide residues in food industry.


Assuntos
Proteínas Fúngicas/química , Hidrolases/química , Malation/química , Metanol/química , Praguicidas/química , Pichia/genética , Pichia/metabolismo , Biocatálise , Biodegradação Ambiental , Cucumis sativus/química , Meios de Cultura/metabolismo , Detergentes/química , Detergentes/metabolismo , Estabilidade Enzimática , Fermentação , Contaminação de Alimentos/análise , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Hidrolases/genética , Hidrolases/metabolismo , Cinética , Malation/metabolismo , Malus/química , Metanol/metabolismo , Organofosfatos/química , Organofosfatos/metabolismo , Praguicidas/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
18.
Bioresour Bioprocess ; 4(1): 37, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28845382

RESUMO

OBJECTIVES: To improve the fermentation production of transglutaminase (TGase) from Streptomyces mobaraensis for applications in the food industry, the atmospheric and room-temperature plasma (ARTP) mutagenesis was applied to breed S. mobaraensis mutants with increased TGase production. RESULTS: After eight rounds of iterative ARTP mutagenesis, four genetically stable mutants, Sm5-V1, Sm6-V13, Sm2-V10, and Sm7-V12, were identified, which showed increased TGase production by 27, 24, 24, and 19%, respectively. The best mutant Sm5-V1 exhibited a maximum TGase activity of 5.85 U/mL during flask fermentation. Compared to the wild-type strain, the transcription levels of the zymogen TGase genes in the mutants increased significantly as indicated by quantitative real-time PCR, while the gene nucleotide sequences of the mutants did not change at all. It was shown that the overexpression of TGase zymogen gene in the mutants contributes to the increase in TGase production. CONCLUSIONS: ARTP is a potentially efficient tool for microbial mutation breeding to bring some significant changes required for the industrial applications.

19.
Enzyme Microb Technol ; 93-94: 11-17, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27702470

RESUMO

A methyl parathion hydrolase (MPH) gene, bjmpd, was cloned from a newly isolated MP-degrading bacterial strain, Burkholderia jiangsuensis MP-1T and heterologously expressed in Escherichia coli BL21 (DE3). Although the amino acid sequence of the bjmpd-encoded enzyme, named BjMPH, differed from that of MPH from Pseudomonas sp. WBC-3 (PsMPH) in only three residues, Ser132, Val247 and Ala267, a significantly higher specific activity towards MP was exhibited by BjMPH than PsMPH. Among them, Ala267 was identified as a key site affecting the catalytic efficiency, and it was rather conservative (Ala or Ser) in homologous proteins, suggesting that a simple substitution of the residue in conservative site with another conservative residue based on the consensus sequence approach might possibly enhance the catalytic efficiency of the MP-degrading enzyme. Inspired by such an observation, we identified a new mutant, BjMPHT64N, exhibiting 3.78-fold higher catalytic efficiency (kcat/KM) towards MP than its wild-type, reaching 4.20×106M-1s-1. The mutant BjMPHT64N also displayed enhanced reactivities (kcat/KM) towards other organophosphorus pesticides. Homology-modelling analysis indicates that enhanced polar contacts of the 64th residue in this mutant may contribute to stabilizing the structure of the enzyme and promote the interactions between enzyme and substrate. This study generated an efficient MP-degrading enzyme, and provides useful information for enhancing the catalytic efficiency of MPHs via conservative residue substitution based on the consensus approach.


Assuntos
Proteínas de Bactérias/metabolismo , Metil Paration/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Substituição de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biodegradação Ambiental , Burkholderia/enzimologia , Burkholderia/genética , Domínio Catalítico/genética , Sequência Consenso , Sequência Conservada , Evolução Molecular Direcionada , Estabilidade Enzimática , Genes Bacterianos , Ligação de Hidrogênio , Inseticidas/metabolismo , Cinética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Monoéster Fosfórico Hidrolases/química , Monoéster Fosfórico Hidrolases/genética , Filogenia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia Estrutural de Proteína
20.
J Biotechnol ; 195: 67-71, 2015 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-25449542

RESUMO

A novel NAD(+)-dependent D-mandelate dehydrogenase was identified from Lactobacillus brevis (LbDMDH). After purified to homogeneity, the optimum pH and temperature for oxidation of D-mandelate were pH 10.0 and 40 °C, and the Km and kcat were 1.1 mM and 355 s(-1) respectively. Employing the LbDMDH together with a mandelate racemase from Pseudomonas putida and a leucine dehydrogenase (EsLeuDH) from Exiguobacterium sibiricum, we established a three-step one-pot domino reaction system for preparing chiral L-phenylglycine from racemic mandelic acid with internal cofactor recycling. Under the optimum conditions, 30.4 g rac-mandelic acid (0.2 M) at 1L scale had been converted into chiral L-phenylglycine, with 96.4% conversion, 86.5% isolation yield, >99% eep and 50.4 gL(-1)d(-1) space-time yield.


Assuntos
Oxirredutases do Álcool/metabolismo , Proteínas Fúngicas/metabolismo , Glicina/análogos & derivados , Racemases e Epimerases/metabolismo , Oxirredutases do Álcool/química , Oxirredutases do Álcool/isolamento & purificação , Reatores Biológicos , Proteínas Fúngicas/química , Proteínas Fúngicas/isolamento & purificação , Glicina/química , Glicina/metabolismo , Lactobacillus/enzimologia , Ácidos Mandélicos/metabolismo , Pseudomonas putida/enzimologia , Racemases e Epimerases/química , Racemases e Epimerases/isolamento & purificação , Estereoisomerismo
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