Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 103
Filtrar
1.
Nat Commun ; 15(1): 3356, 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38637502

RESUMO

To realize economically feasible electrochemical CO2 conversion, achieving a high partial current density for value-added products is particularly vital. However, acceleration of the hydrogen evolution reaction due to cathode flooding in a high-current-density region makes this challenging. Herein, we find that partially ligand-derived Ag nanoparticles (Ag-NPs) could prevent electrolyte flooding while maintaining catalytic activity for CO2 electroreduction. This results in a high Faradaic efficiency for CO (>90%) and high partial current density (298.39 mA cm‒2), even under harsh stability test conditions (3.4 V). The suppressed splitting/detachment of Ag particles, due to the lipid ligand, enhance the uniform hydrophobicity retention of the Ag-NP electrode at high cathodic overpotentials and prevent flooding and current fluctuations. The mass transfer of gaseous CO2 is maintained in the catalytic region of several hundred nanometers, with the smooth formation of a triple phase boundary, which facilitate the occurrence of CO2RR instead of HER. We analyze catalyst degradation and cathode flooding during CO2 electrolysis through identical-location transmission electron microscopy and operando synchrotron-based X-ray computed tomography. This study develops an efficient strategy for designing active and durable electrocatalysts for CO2 electrolysis.

2.
Crit Rev Biotechnol ; 44(3): 373-387, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-36775664

RESUMO

Porphyrins, phycobilins, and their proteins have abundant π-electrons and strongly absorb visible light, some of which bind a metal ion in the center. Because of the structural and optical properties, they not only play critical roles as an essential component in natural systems but also have attracted much attention as a high value specialty chemical in various fields, including renewable energy, cosmetics, medicines, and foods. However, their commercial application seems to be still limited because the market price of porphyrins and phycobilins is generally expensive to apply them easily. Furthermore, their petroleum-based chemical synthesis is energy-intensive and emits a pollutant. Recently, to replace petroleum-based production, many studies on the bioproduction of metalloporphyrins, including Zn-porphyrin, Co-porphyrin, and heme, porphyrin derivatives including chlorophyll, biliverdin, and phycobilins, and their proteins including hemoproteins, phycobiliproteins, and phytochromes from renewable carbon sources using microbial cell factories have been reported. This review outlines recent advances in the bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories developed by various microbial biotechnology techniques, provides well-organized information on metabolic regulations of the porphyrin metabolism, and then critically discusses challenges and future perspectives. Through these, it is expected to be able to achieve possible solutions and insights and to develop an outstanding platform to be applied to the industry in future research.


Assuntos
Metaloporfirinas , Petróleo , Porfirinas , Ficobilinas , Engenharia Metabólica
3.
Surg Radiol Anat ; 45(12): 1593-1597, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37897524

RESUMO

OBJECTIVE: To locate the intramuscular nerve branches of the flexor digitorum superficialis (FDS) and determine the accurate site for botulinum toxin injection. DESIGN: This study anatomically dissected 24 arms of 12 fresh adult cadavers to find intramuscular nerve endings in the FDS. The motor branch points (MBPs), proximal limit points (PLPs), and distal limit points (DLPs) of the terminal intramuscular nerve endings were identified. These three parameters were expressed in longitudinal and transverse coordinates in relation to the FDS driving as a reference line. RESULTS: The mean length of the reference line was 234.6 ± 11.2 mm. In the longitudinal coordinate, the MBPs, PLPs, and DLPs were located at 41.6% (standard deviation (SD) 2.6%), 35.1% (SD 4.1%), and 53.4% (SD 4.6%) of the reference line in the first main branch and 72.4% (SD 4.5%), 67.5% (SD 1.5%), and 82.0% (SD 5.7%) in the second main branch, respectively. The mean value of the transverse coordinate was not greatly deviated from the reference line. CONCLUSION: The MBPs of the first and second main branches are located approximately 41.6% and 72.4% of the reference line, which considers the FDS direction, respectively. This finding helps determine the optimal injection site for botulinum toxin in the FDS.


Assuntos
Toxinas Botulínicas , Adulto , Humanos , Músculo Esquelético/inervação , Antebraço/inervação , Mãos , Dedos
4.
Drug Saf ; 46(7): 647-660, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37243963

RESUMO

INTRODUCTION: With the availability of retrospective pharmacovigilance data, the common data model (CDM) has been identified as an efficient approach towards anonymized multicenter analysis; however, the establishment of a suitable model for individual medical systems and applications supporting their analysis is a challenge. OBJECTIVE: The aim of this study was to construct a specialized Korean CDM (K-CDM) for pharmacovigilance systems based on a clinical scenario to detect adverse drug reactions (ADRs). METHODS: De-identified patient records (n = 5,402,129) from 13 institutions were converted to the K-CDM. From 2005 to 2017, 37,698,535 visits, 39,910,849 conditions, 259,594,727 drug exposures, and 30,176,929 procedures were recorded. The K-CDM, which comprises three layers, is compatible with existing models and is potentially adaptable to extended clinical research. Local codes for electronic medical records (EMRs), including diagnosis, drug prescriptions, and procedures, were mapped using standard vocabulary. Distributed queries based on clinical scenarios were developed and applied to K-CDM through decentralized or distributed networks. RESULTS: Meta-analysis of drug relative risk ratios from ten institutions revealed that non-steroidal anti-inflammatory drugs (NSAIDs) increased the risk of gastrointestinal hemorrhage by twofold compared with aspirin, and non-vitamin K anticoagulants decreased cerebrovascular bleeding risk by 0.18-fold compared with warfarin. CONCLUSION: These results are similar to those from previous studies and are conducive for new research, thereby demonstrating the feasibility of K-CDM for pharmacovigilance. However, the low quality of original EMR data, incomplete mapping, and heterogeneity between institutions reduced the validity of the analysis, thus necessitating continuous calibration among researchers, clinicians, and the government.


Assuntos
Registros Eletrônicos de Saúde , Farmacovigilância , Humanos , Sistemas de Notificação de Reações Adversas a Medicamentos , Eletrônica , Estudos Multicêntricos como Assunto , República da Coreia/epidemiologia , Estudos Retrospectivos
5.
Eur J Clin Microbiol Infect Dis ; 42(6): 691-700, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37012540

RESUMO

This study aimed to assess the performance of our in-house method for rapid direct bacterial identification (ID) and antimicrobial susceptibility testing (AST) using a positive blood culture (BC) broth. For Gram-negative bacteria, 4 mL of BC broth was aspirated and passed through a Sartorius Minisart syringe filter with a pore size of 5 µm. The filtrate was then centrifuged and washed. A small volume of the pellet was used for ID, using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and for AST, using automated broth microdilution. For Gram-positive cocci, 4 mL of BC broth was passed through the Minisart syringe filter. Then, 4 mL of sterile distilled water was injected in the direction opposite to that of the filtration to collect the bacterial residue trapped in the filter. Compared with the conventional method performed with pure colonies on agar plates, 94.0% (234/249) were correctly identified using the in-house method, with rates of 91.4% (127/139) and 97.3% (107/110) for Gram-positive and Gram-negative isolates, respectively. Of 234 correctly identified isolates, 230 were assessed by AST. Categorical agreement and essential agreement were 93.3% and 94.5%, respectively, with a minor error rate of 3.8%, a major error rate of 3.4%, and a very major error rate of 1.6%. Our in-house preparation method showed good performance in rapid direct ID and AST using positive BC broths compared to the conventional method. This simple method can shorten the conventional turnaround time for ID and AST by at least 1 day, potentially contributing to better patient management.


Assuntos
Antibacterianos , Bacteriemia , Humanos , Antibacterianos/farmacologia , Hemocultura/métodos , Testes de Sensibilidade Microbiana , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Bactérias , Bactérias Gram-Negativas , Bacteriemia/diagnóstico , Bacteriemia/microbiologia
6.
Manag Int Rev ; 63(2): 247-284, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36776758

RESUMO

Drawing from the literature on institutional pressure, we argue that firms with different ownership types have different strategic options in domestic and overseas markets, namely the zone of conformity. State-controlled enterprises (SCEs) have a broader range of acceptable actions than do private-controlled enterprises (PCEs) in a domestic market but face more sanctions and stricter conformity requests in an overseas market. The concept of the zone of conformity predicts SCEs have a higher probability of deal failure overseas than in domestic markets and strategically seek less equity ownership of target firms in cross-border deals. The autocracy level of target country moderates the M&A behaviors difference between SCEs and PCEs. Our analysis of 12,497 Chinese mergers and acquisitions supports the study hypotheses. Supplementary Information: The online version contains supplementary material available at 10.1007/s11575-023-00501-9.

7.
Clin Biochem ; 113: 52-58, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36627011

RESUMO

BACKGROUND: Ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) is a reliable and accurate method for measuring steroid hormone levels. There is an increasing need for sensitive and precise methods to measure estradiol in pediatric patients. Here, we established reference intervals for estradiol in healthy children using a UHPLC-MS/MS-based method for the first time in South Korea. METHODS: Serum estradiol was measured using a Sciex Triple QuadTM 6500 + UHPLC-MS/MS (Sciex, Framingham, MA, USA). Reference intervals for estradiol were established according to the CLSI document EP28-A3c:2008. The reference intervals were validated using serum samples from 634 pediatric patients, including neonates, children, and adolescents. Among them, 389 specimens were used in analysis of the specimen acceptance time. Statistical analysis was performed using MedCalc (MedCalc, Ostend, Belgium) and Analyse-it (Analyse-it Software Ltd., Leeds, United Kingdom) software. RESULTS: Reference intervals for boys (n = 297) were <16.6, <7.3, <19.0, <30.5, 7.6-96.5, and 10.6-134.4 pmol/L among those aged <1, 1-5, 6-9, 10-11, 12-14, and 15-17 years, respectively. Reference intervals for girls (n = 337) were <114.7, <24.2, <34.8, 8.0-177.0, 10.4-480.5, and 9.1-486.7 pmol/L among those aged <1, 1-5, 6-9, 10-11, 12-14, and 15-17 years, respectively. Overall, there was no effect of specimen acceptance time on estradiol measurements in boys or girls, except for that in the group aged 10-11 years. CONCLUSIONS: The reference intervals for healthy children were validated using a UHPLC-MS/MS-based method. The highly analytical sensitive UHPLC-MS/MS method may be useful for estradiol determination in pediatric patients.


Assuntos
Estradiol , Espectrometria de Massas em Tandem , Masculino , Feminino , Adolescente , Recém-Nascido , Humanos , Criança , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem/métodos , Valores de Referência , Software
8.
Clin Biochem ; 113: 59-63, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36627012

RESUMO

BACKGROUND: There is an increased need for the sensitive and accurate measurement of estradiol levels in patients with estradiol-related endocrine disorders. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a reliable and accurate method for measuring steroid hormone levels. Here, we aimed to establish an LC-MS/MS-based method to quantify estradiol levels without sample derivatization and evaluated its analytical performance. METHODS: Sciex Triple Quad 6500 + LC-MS/MS was used for estradiol analysis. We evaluated its analytical performance, including linearity, precision, the lower limit of detection and quantification (LoD and LoQ, respectively), accuracy, and carryover. The estradiol results determined by LC-MS/MS were compared with those obtained using a chemiluminescent microparticle immunoassay. RESULTS: The LC-MS/MS output was linear for serum estradiol concentrations in the range of 0.2-10311.6 pmol/L. The intra-laboratory precision (coefficient of variation) was 3.0-10.1 %. The LoD and LoQ were 2.8 and 7.5 pmol/L, respectively. The overall accuracy was within 15 % of bias, and the carryover was within the acceptable range (<1.0 %). The results of the estradiol analysis determined by LC-MS/MS were comparable to those obtained by the chemiluminescent microparticle immunoassay (r2 = 0.9843), although there was a negative bias of - 17.82 (95 % confidence interval, -27.21 to - 8.44). CONCLUSIONS: A highly sensitive, derivatization-free LC-MS/MS method was successfully developed in this study. This may be beneficial for estradiol measurements in patients with estradiol-related endocrine disorders.


Assuntos
Estradiol , Espectrometria de Massas em Tandem , Humanos , Cromatografia Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Técnicas Imunoenzimáticas , Reprodutibilidade dos Testes
9.
Medicine (Baltimore) ; 101(44): e31367, 2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36343044

RESUMO

BACKGROUND: Botulinum toxin type A injection is widely used treatment option for the treatment of upper limb spasticity in stroke patients. The purpose of this study was to explore the safety and efficacy of MT10107, a new botulinum toxin type A, in patients with post-stroke upper limb spasticity. METHODS: A prospective, randomized, double-blind, active drug-controlled, multi-center, phase I clinical trial. Thirty patients with post-stroke upper limb spasticity were received either MT10107 or onabotulinumtoxinA. Primary endpoint was change of modified Ashworth scale (MAS) score for wrist flexor from baseline to week 4. The secondary endpoints were changes of MAS scores for elbow and finger flexors, response rate, Disability Assessment Scale (DAS), and global assessment of treatment. The safety endpoints such as adverse events, vital signs, physical examination, and laboratory test were evaluated. The outcome measures were evaluated from baseline to week 4. RESULTS: The primary endpoints were -1.07 ± 0.70 and -1.23 ± 0.56 for the MT10107 and onabotulinumtoxinA groups, respectively. The intergroup difference of change between the 2 groups was 0.17 (95% confidence interval -0.31 to 0.64, P = .5769). In secondary endpoints, both groups showed a significant improvement in both MAS and DAS. There was no significant between-group difference in all secondary endpoints and safety measures. CONCLUSION: The safety and efficacy of MT10107 showed no significant difference compared to onabotulinumtoxinA in post-stroke upper limb spasticity treatment.


Assuntos
Toxinas Botulínicas Tipo A , Fármacos Neuromusculares , Acidente Vascular Cerebral , Humanos , Toxinas Botulínicas Tipo A/uso terapêutico , Método Duplo-Cego , Espasticidade Muscular/tratamento farmacológico , Espasticidade Muscular/etiologia , Fármacos Neuromusculares/uso terapêutico , Estudos Prospectivos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/tratamento farmacológico , Resultado do Tratamento , Extremidade Superior
10.
Bioresour Technol ; 362: 127758, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35963485

RESUMO

A novel whole cell biocatalyst using fungal-pretreated lignocellulosic biomass was developed by displaying the enzyme complex consisting of N-acetylglucosaminidase (cNAG) and endoglucanse E (cCelE) on Corynebacterium glutamicum, hereafter called mNC. mNC showed a maximum 4.43-fold cNAG and 2.40-fold cCelE activity compared to single enzyme-secreting C. glutamicum. mNC also showed the highest efficiency of sugar production in various types of cellulose and fungal-pretreated biomass. The growth of mNC was 5.06-fold higher than that of the control. Then, the ability of mNC to produce a valuable chemical was confirmed. mNC overexpressing isopropanol biosynthesis genes showed a maximum titer of 218.9 ± 11.73 mg/L isopropanol and maintained high efficiency for isopropanol production in the recycling test, which was 90.07 ± 4.12 % during 4 cycles. This strategy can be applied to the direct saccharification of fungal-pretreated lignocellulosic biomass efficiently leading to the production of valuable products in various industrial fields.


Assuntos
Corynebacterium glutamicum , 2-Propanol , Biomassa , Corynebacterium glutamicum/metabolismo , Lignina/metabolismo , Complexos Multienzimáticos/metabolismo
11.
PLoS One ; 17(7): e0271516, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35862390

RESUMO

Adjuvant use of geraniol, a plant essential oil component, is known to increase the efficacy of antibiotics by acting as a potent inhibitor of efflux mechanisms. In this study, we assessed the effect of a geraniol-antibiotic combination in 21 Acinetobacter baumannii clinical isolates consisting of high efflux (HE) and low efflux (LE) activity groups. We determined the MIC for geraniol and the four antibiotics and evaluated the adjuvant antimicrobial activity and resensitization efficacy of adjuvant geraniol. Geraniol-antibiotic combinations significantly reduced the MIC of all four antibiotics (P < 0.0001), and the fold change in MIC decreased by 4 to >256-fold for tigecycline, >16 to >4,096-fold for ceftazidime, 1 to >4,096-fold for cefepime, and >2 to >4096-fold for ciprofloxacin. Importantly, geraniol showed adjuvant antimicrobial activity and resensitization efficacy when used in combination with antibiotics in 21 A. baumannii clinical isolates. However, there was no statistically significant difference between the HE and LE groups. Low concentrations (0.125% and 0.0625%) of geraniol showed no cytotoxic or hemolytic activity. Our study shows that geraniol, acting as an antibiotic adjuvant, is a good candidate for in vivo studies of combination therapy for the treatment of MDR/XDR A. baumannii infections.


Assuntos
Acinetobacter baumannii , Monoterpenos Acíclicos , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Sinergismo Farmacológico , Testes de Sensibilidade Microbiana
12.
Sci Total Environ ; 842: 156890, 2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-35753492

RESUMO

Poly(ethylene terephthalate) (PET) is synthesized via a rich ester bond between terephthalate (TPA) and ethylene glycol (EG). Because of this, PET degradation takes a long time and PET accumulates in the environment. Many studies have been conducted to improve PET degrading enzyme to increase the efficiency of PET depolymerization. However, enzymatic PET decomposition is still restricted, making upcycling and recycling difficult. Here, we report a novel PET degrading complex composed of Ideonella sakaiensis PETase and Candida antarctica lipase B (CALB) that improves degradability, binding ability and enzyme stability. The reaction mechanism of chimeric PETase (cPETase) and chimeric CALB (cCALB) was confirmed by PET and bis (2-hydroxyethyl terephthalate) (BHET). cPETase generated BHET and mono (2-hydroxyethyl terephthalate (MHET) and cCALB produced terephthalate (TPA). Carbohydrate binding module 3 (CBM3) in the scaffolding protein greatly improved PET film binding affinity. Finally, the final enzyme complex demonstrated a 6.5-fold and 8.0-fold increase in the efficiency of hydrolysis from PET with either high crystalline or waste to TPA than single enzymes, respectively. This complex could effectively break down waste PET while maintaining enzyme stability and would be applied for biological upcycling of TPA.


Assuntos
Ácidos Ftálicos , Polietilenotereftalatos , Etilenos , Ácidos Ftálicos/metabolismo , Plásticos/metabolismo , Polietilenotereftalatos/química
13.
Nat Commun ; 13(1): 2205, 2022 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-35459916

RESUMO

The electrosynthesis of formate from CO2 can mitigate environmental issues while providing an economically valuable product. Although stannic oxide is a good catalytic material for formate production, a metallic phase is formed under high reduction overpotentials, reducing its activity. Here, using a fluorine-doped tin oxide catalyst, a high Faradaic efficiency for formate (95% at 100 mA cm-2) and a maximum partial current density of 330 mA cm-2 (at 400 mA cm-2) is achieved for the electroreduction of CO2. Furthermore, the formate selectivity (≈90%) is nearly constant over 7 days of operation at a current density of 100 mA cm-2. In-situ/operando spectroscopies reveal that the fluorine dopant plays a critical role in maintaining the high oxidation state of Sn, leading to enhanced durability at high current densities. First-principle calculation also suggests that the fluorine-doped tin oxide surface could provide a thermodynamically stable environment to form HCOO* intermediate than tin oxide surface. These findings suggest a simple and efficient approach for designing active and durable electrocatalysts for the electrosynthesis of formate from CO2.

14.
Bioresour Technol ; 354: 127171, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35472638

RESUMO

Isopropanol is a commodity chemical widely used as a biofuel, fuel additive, rubbing alcohol and intermediate in various fields. Here, an engineered Corynebacterium glutamicum overproducing isopropanol was developed. To our knowledge, despite a representative industrial host to produce valuable chemicals, the high-level production of isopropanol in C. glutamicum has never been reported. First, the problem of the inability to produce isopropanol was solved by finding a key factor in its metabolism. The consolidation and modular optimization of synthetic bypasses including succinate and mevalonate bypasses enhanced isopropanol production. Flux redistribution of central metabolism significantly directed the carbon flux toward isopropanol biosynthesis. The final engineered strain produced 10.25 ± 1.12 g/L isopropanol in two-stage fed-batch fermentation with an optimized gas stripping, which is the highest titer, yield and productivity in C. glutamicum. These strategies could be useful for the high-level production of isopropanol in C. glutamicum.


Assuntos
Corynebacterium glutamicum , 2-Propanol , Corynebacterium glutamicum/metabolismo , Fermentação , Engenharia Metabólica , Ácido Succínico/metabolismo
15.
Diagn Microbiol Infect Dis ; 103(1): 115658, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35299130

RESUMO

This study compared the accuracy of a new MALDI-TOF mass spectrometry system, ASTA MicroIDSys system, with that of MALDI Biotyper system for the identification of reference and clinical bacterial and yeast strains. The identification accuracy of the 2 systems was compared using a total of 406 strains comprising 142 aerobic and 180 anaerobic bacterial strains and 84 yeast strains. The genus and species identification rates were 98.0% and 89.4% using MicroIDSys and 96.1% and 89.4% using Biotyper, respectively. The species identification rates of MicroIDSys and Biotyper for aerobic bacteria were 93.0% and 97.2%, respectively, and those for anaerobic bacteria were 85.6% and 81.7%, respectively. The accuracy of yeast identification at the species level was 91.7% using MicroIDSys and 92.9% using Biotyper. These findings indicate that MicroIDSys could be useful for the accurate identification of bacteria and yeast in clinical microbiology laboratories.


Assuntos
Bactérias , Saccharomyces cerevisiae , Bactérias/química , Humanos , Lasers , República da Coreia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos
16.
Nat Commun ; 13(1): 605, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-35105874

RESUMO

Computational calculations and experimental studies reveal that the CoOOH phase and the intermediate-spin (IS) state are the key factors for realizing efficient Co-based electrocatalysts for the oxygen evolution reaction (OER). However, according to thermodynamics, general cobalt oxide converts to the CoO2 phase under OER condition, retarding the OER kinetics. Herein, we demonstrate a simple and scalable strategy to fabricate electrodes with maintaining Fe-CoOOH phase and an IS state under the OER. The changes of phase and spin states were uncovered by combining in-situ/operando X-ray based absorption spectroscopy and Raman spectroscopy. Electrochemical reconstruction of chalcogenide treated Co foam affords a highly enlarged active surface that conferred excellent catalytic activity and stability in a large-scale water electrolyzer. Our findings are meaningful in that the calculated results were experimentally verified through the operando analyses. It also proposes a new strategy for electrode fabrication and confirms the importance of real active phases and spin states under a particular reaction condition.

17.
J Agric Food Chem ; 70(5): 1516-1524, 2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-35088592

RESUMO

l-Ergothioneine (EGT) is a strong antioxidant used in industry, and it is commonly extracted from mushrooms; however, its production is limited. As an alternative, we developed metabolically engineered Corynebacterium glutamicum with reinforced sulfur assimilation and pentose phosphate pathways, which led to the accumulation of 45.0 and 63.2 mg/L EGT, respectively. Additionally, the overexpression of cysEKR resulted in further promoted EGT production in ET4 (66.5 mg/L) and ET7 (85.0 mg/L). Based on this result, we developed the strain ET11, in which all sulfur assimilatory, PP, and l-cysteine synthetic pathways were reinforced, and it synthesized 264.4 mg/L EGT. This study presents the first strategy for EGT synthesis that does not require precursor addition in C. glutamicum, and the production time was shortened. In addition, the synthesized EGT showed high radical scavenging activity (70.7%), thus confirming its antioxidant function. Consequently, this study showed the possibility of EGT commercialization by overcoming the limitations of industrial processes.


Assuntos
Agaricales , Corynebacterium glutamicum , Ergotioneína , Antioxidantes , Corynebacterium glutamicum/genética , Aditivos Alimentares
18.
Small ; 18(8): e2105087, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34894074

RESUMO

The diamond-graphite hybrid thin film with low-dimensional nanostructure (e.g., nitrogen-included ultrananocrystalline diamond (N-UNCD) or the alike), has been employed in many impactful breakthrough applications. However, the detailed picture behind the bottom-up evolution of such intriguing carbon nanostructure is far from clarified yet. Here, the authors clarify it, through the concerted efforts of microscopic, physical, and electrochemical analyses for a series of samples synthesized by hot-filament chemical vapor deposition using methane-hydrogen precursor gas, based on the hydrogen-dependent surface reconstruction of nanodiamond and on the substrate-temperature-dependent variation of the growth species (atomic hydrogen and methyl radical) concentration near substrate. The clarified picture provides insights for a drastic enhancement in the electrochemical activities of the hybrid thin film, concerning the detection of important biomolecule, that is, ascorbic acid, uric acid, and dopamine: their limits of detections are 490, 35, and 25 nm, respectively, which are among the best of the all-carbon thin film electrodes in the literature. This work also enables a simple and effective way of strongly enhancing AA detection.


Assuntos
Grafite , Nanoestruturas , Diamante/química , Dopamina/análise , Técnicas Eletroquímicas , Eletrodos , Grafite/química , Nanoestruturas/química
19.
Microbiol Immunol ; 65(12): 566-574, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34516008

RESUMO

The performance of the ASTA MicroIDSys system (ASTA), a new matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) system, was evaluated for the identification of viridans group streptococci (VGS) and compared with the results obtained with the Bruker Biotyper system (Bruker Daltonics). A total of 106 Streptococcus reference strains belonging to 24 species from the bacterial strain bank was analyzed using the two MALDI-TOF MS systems. Of the 106 reference strains tested, ASTA MicroIDSys and Bruker Biotyper correctly identified 84.9% and 81.1% at the species level, 100% and 97.2% at the group level and 100% and 98.1% at the genus level, respectively. The difference between the two systems was not statistically significant (P = 0.289). Out of 24 species, 13 species were accurately identified to the species level with 100% accurate identification rates with both systems. The accurate identification rates at the species level of ASTA MicroIDSys and Bruker Biotyper were 100% and 87.5% for the S. anginosus group; 78.4% and 73.5% for the S. mitis group; 91.7% and 91.7% for the S. mutans group; and 100% and 100% for the S. salivarius group, respectively. The ASTA MicroIDSys showed an identification performance equivalent to that of the Bruker Biotyper for VGS. Therefore, it would be useful for the identification of VGS strains in clinical microbiology laboratories.


Assuntos
Bactérias , Estreptococos Viridans , Lasers , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
20.
J Agric Food Chem ; 69(40): 11912-11918, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34586795

RESUMO

Metabolic engineering of non-photosynthetic microorganisms to increase the utilization of CO2 has been focused on as a green strategy to convert CO2 into valuable products such as fatty acids. In this study, a CO2 utilization pathway involving carbonic anhydrase and biotin carboxylase was formed to recycle CO2 in the oleaginous yeast Yarrowia lipolytica, thereby increasing the production of fatty acids. In the recombinant strain in which the CO2 utilization pathway was introduced, the production of fatty acids was 10.7 g/L, which was 1.5-fold higher than that of the wild-type strain. The resulting strain had a 1.4-fold increase in dry cell mass compared to the wild-type strain. In addition, linoleic acid was 47.7% in the fatty acid composition of the final strain, which was increased by 11.6% compared to the wild-type strain. These results can be applied as an essential technology for developing efficient and eco-friendly processes by directly utilizing CO2.


Assuntos
Yarrowia , Dióxido de Carbono , Ácidos Graxos , Engenharia Metabólica , Yarrowia/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...