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1.
Cereb Cortex ; 34(9)2024 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-39315647

RESUMEN

While some studies have used a transdiagnostic approach to relate depression to metabolic or functional brain alterations, the structural substrate of depression across clinical diagnostic categories is underexplored. In a cross-sectional study of 52 patients with major depressive disorder and 51 with post-traumatic stress disorder, drug-naïve, and spanning mild to severe depression severity, we examined transdiagnostic depressive correlates with regional gray matter volume and the topological properties of gray matter-based networks. Locally, transdiagnostic depression severity correlated positively with gray matter volume in the right middle frontal gyrus and negatively with nodal topological properties of gray matter-based networks in the right amygdala. Globally, transdiagnostic depression severity correlated positively with normalized characteristic path length, a measure implying brain integration ability. Compared with 62 healthy control participants, both major depressive disorder and post-traumatic stress disorder patients showed altered nodal properties in regions of the fronto-limbic-striatal circuit, and global topological organization in major depressive disorder in particular was characterized by decreased integration and segregation. These findings provide evidence for a gray matter-based structural substrate underpinning depression, with the prefrontal-amygdala circuit a potential predictive marker for depressive symptoms across clinical diagnostic categories.


Asunto(s)
Amígdala del Cerebelo , Trastorno Depresivo Mayor , Sustancia Gris , Imagen por Resonancia Magnética , Corteza Prefrontal , Trastornos por Estrés Postraumático , Humanos , Masculino , Trastorno Depresivo Mayor/diagnóstico por imagen , Trastorno Depresivo Mayor/fisiopatología , Femenino , Trastornos por Estrés Postraumático/diagnóstico por imagen , Trastornos por Estrés Postraumático/fisiopatología , Trastornos por Estrés Postraumático/patología , Adulto , Corteza Prefrontal/diagnóstico por imagen , Corteza Prefrontal/patología , Amígdala del Cerebelo/diagnóstico por imagen , Amígdala del Cerebelo/patología , Imagen por Resonancia Magnética/métodos , Estudios Transversales , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Persona de Mediana Edad , Vías Nerviosas/diagnóstico por imagen , Vías Nerviosas/patología , Índice de Severidad de la Enfermedad , Adulto Joven
2.
Phys Rev Lett ; 130(25): 250801, 2023 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-37418722

RESUMEN

Secure key rate (SKR) of point-point quantum key distribution (QKD) is fundamentally bounded by the rate-loss limit. Recent breakthrough of twin-field (TF) QKD can overcome this limit and enables long distance quantum communication, but its implementation necessitates complex global phase tracking and requires strong phase references that not only add to noise but also reduce the duty cycle for quantum transmission. Here, we resolve these shortcomings, and importantly achieve even higher SKRs than TF-QKD, via implementing an innovative but simpler measurement-device-independent QKD that realizes repeaterlike communication through asynchronous coincidence pairing. Over 413 and 508 km optical fibers, we achieve finite-size SKRs of 590.61 and 42.64 bit/s, which are respectively 1.80 and 4.08 times of their corresponding absolute rate limits. Significantly, the SKR at 306 km exceeds 5 kbit/s and meets the bitrate requirement for live one-time-pad encryption of voice communication. Our work will bring forward economical and efficient intercity quantum-secure networks.

3.
Microb Cell Fact ; 21(1): 35, 2022 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-35264166

RESUMEN

BACKGROUND: D-Xylonic acid is a versatile platform chemical with broad potential applications as a water reducer and disperser for cement and as a precursor for 1,4-butanediol and 1,2,4-tributantriol. Microbial production of D-xylonic acid with bacteria such as Gluconobacter oxydans from inexpensive lignocellulosic feedstock is generally regarded as one of the most promising and cost-effective methods for industrial production. However, high substrate concentrations and hydrolysate inhibitors reduce xylonic acid productivity. RESULTS: The D-xylonic acid productivity of G. oxydans DSM2003 was improved by overexpressing the mGDH gene, which encodes membrane-bound glucose dehydrogenase. Using the mutated plasmids based on pBBR1MCS-5 in our previous work, the recombinant strain G. oxydans/pBBR-R3510-mGDH was obtained with a significant improvement in D-xylonic acid production and a strengthened tolerance to hydrolysate inhibitors. The fed-batch biotransformation of D-xylose by this recombinant strain reached a high titer (588.7 g/L), yield (99.4%), and volumetric productivity (8.66 g/L/h). Moreover, up to 246.4 g/L D-xylonic acid was produced directly from corn stover hydrolysate without detoxification at a yield of 98.9% and volumetric productivity of 11.2 g/L/h. In addition, G. oxydans/pBBR-R3510-mGDH exhibited a strong tolerance to typical inhibitors, i.e., formic acid, furfural, and 5-hydroxymethylfurfural. CONCLUSION: Through overexpressing mgdh in G. oxydans, we obtained the recombinant strain G. oxydans/pBBR-R3510-mGDH, and it was capable of efficiently producing xylonic acid from corn stover hydrolysate under high inhibitor concentrations. The high D-xylonic acid productivity of G. oxydans/pBBR-R3510-mGDH made it an attractive choice for biotechnological production.


Asunto(s)
Gluconobacter oxydans , Fermentación , Gluconobacter oxydans/genética , Gluconobacter oxydans/metabolismo , Xilosa/análogos & derivados , Xilosa/metabolismo , Zea mays/metabolismo
4.
Opt Express ; 29(10): 14505-14512, 2021 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-33985172

RESUMEN

Time transfer based on phase modulation schemes has attracted extensive attention in recent years. We propose and experimentally demonstrate an adjustable and stable Michelson interferometer (MI) with a DC phase tracking algorithm for two-way time transfer. Time signal with one pulse per second (1 PPS) is loaded on an optical carrier modulated in phase and demodulated by a Michelson interferometer. The whole compact and cost-effective demodulator is symmetrical with a single coupler to split and recombine optical waves, flexible with one photodetector and a bias tee to separate the DC signal and recovery pulses and stable with a phase modulator to compensate for the drift-phase noise. We show the implementation of modulation and demodulation of the time signal and obtain the stability of 2.31 × 10-11 at 1000 s averaging time. We then demonstrate two-way time transfer over 1556 km lab fibers. The experimental result shows time interval stability of 1 PPS with 5.62 × 10-11 at 1000 s averaging time. It has the potential to transfer time signals in long-distance fiber optic links.

5.
Biotechnol Lett ; 43(10): 2035-2043, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34448097

RESUMEN

OBJECTIVES: 3,4-Dihydroxybutyric acid (3,4-DHBA) is a multifunctional C4 platform compound widely used for the synthesis of various materials, including pharmaceuticals. Although, a biosynthetic pathway for 3,4-DHBA production has been developed, its low yield still precludes large-scale use. Here, a heterologous four-step biosynthetic pathway was established in recombinant Escherichia coli (E. coli) using a combinatorial strategy. RESULTS: Several aldehyde dehydrogenases (ALDHs) were screened, using in vitro enzyme assays, to identify suitable catalysts for the dehydrogenation of 3,4-dihydroxybutanal (3,4-DHB) to 3,4-DHBA. A pathway containing glucose dehydrogenase (BsGDH) from Bacillus subtilis, D-xylonate dehydratase (YagF) from E. coli, benzoylformate decarboxylase (PpMdlC) from Pseudomonas putida and ALDH was introduced into E. coli, generating 3.04 g/L 3,4-DHBA from D-xylose (0.190 g 3,4-DHBA/g D-xylose). Disruption of competing pathways by deleting xylA, ghrA, ghrB and adhP contributed to an 87% increase in 3,4-DHBA accumulation. Expression of a fusion construct containing PpMdlC and YagF enhanced the 3,4-DHBA titer, producing the highest titer and yield reported thus far (7.71 g/L; 0.482 g 3,4-DHBA/g D-xylose). CONCLUSIONS: These results showed that deleting genes from competing pathways and constructing fusion proteins significantly improved the titer and yield of 3,4-DHBA in engineered E. coli.


Asunto(s)
Butileno Glicoles/metabolismo , Butiratos/metabolismo , Escherichia coli , Ingeniería Metabólica/métodos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Vías Biosintéticas/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Xilosa/metabolismo
6.
Dig Dis Sci ; 65(10): 2896-2906, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-31900716

RESUMEN

PURPOSE: Based on previous researches of HoxC6, this study aims to investigate the expression levels of isoforms HoxC6-1 and HoxC6-2 and to explore their roles in gastric carcinogenesis as well as the possible molecular mechanism. METHODS: We investigated expression levels of HoxC6, HoxC6-1, and HoxC6-2 in gastric cancer tissues, coupled with relevant data in TCGA dataset. In vitro, HoxC6, HoxC6-1, and HoxC6-2 knockdown by small interference RNA was carried for evaluating the changes of malignant biological behaviors of gastric cancer cells, such as proliferation, migration, invasion, apoptosis, and cell cycle alternation. Metastasis-related nucleotide lncRNA HOTAIR was selected by bioinformatics, and verification was carried out by in vitro researches. RESULTS: Data suggested HoxC6-1 and HoxC6-2 were considerably over-expressed with different folds in gastric cancerous tissues. Decreased expression of HoxC6-2 was detected in well-differentiated type of gastric cancer. In vitro, the conclusion that HoxC6 functions as a tumor oncogene illuminated by previous studies was verified again. Additionally, down-regulating of HoxC6-2 significantly inhibited SGC-7901 and BGC-823 cells from proliferation, migration, invasion, apoptosis, while quite slight results or none statistically significant results were observed when HoxC6-1 was knockdown. Besides, over-expression of HOTAIR, which is relevant with HoxC6 during gastric carcinogenesis, was detected in gastric cancerous tissues. Restored expression of HoxC6 partially reversed the decreased migration caused by down-regulating HOTAIR in gastric cancer cells. CONCLUSION: HoxC6 acts as an oncogene in gastric carcinogenesis and might be a promising therapeutic target. Isoform HoxC6-2 plays a primary carcinogenic role in gastric carcinogenesis. HOTAIR, over-expressed in gastric cancer, might regulate HoxC6 on the protein level in promoting migration of gastric cells.


Asunto(s)
Carcinogénesis/metabolismo , Proteínas de Homeodominio/metabolismo , Proteínas Oncogénicas/metabolismo , Neoplasias Gástricas/metabolismo , Apoptosis , Carcinogénesis/genética , Carcinogénesis/patología , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Bases de Datos Genéticas , Femenino , Regulación Neoplásica de la Expresión Génica , Proteínas de Homeodominio/genética , Humanos , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Proteínas Oncogénicas/genética , Isoformas de Proteínas , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Transducción de Señal , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología
7.
Opt Express ; 27(26): 38109-38115, 2019 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-31878582

RESUMEN

We demonstrate a radio frequency (RF) phase-stable transmission over fiber based on microwave photonic phase shifter. In the proposed system, both assistant RF signals are applied to drive two arms of a dual-drive Mach-Zehnder modulator (DMZM), respectively. An optical bandpass filter is followed to filter out the first-order sideband of optical modulated signal. Due to the phase independence between two optical sidebands, the phase perturbation caused by fiber-length variations can be compensated automatically via controlling the direct-current bias voltage of the DMZM. We have performed RF transfer in a 155 km single-mode fiber with a frequency instability of 3.05 × 10-17 at 10,000 s averaging time.

8.
Opt Lett ; 42(21): 4517-4520, 2017 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-29088202

RESUMEN

We report on the switchable generation of a rectangular noise-like pulse (NLP) and a dissipative soliton resonance (DSR) in a fiber laser with highly nonlinear effect at very low pump power. The NLP centered at 1530.5 nm demonstrates a new characteristic that its profile evolves gradually from rectangular shape to Gaussian-like shape with the increasing pump power. By appropriately manipulating the polarization controller (PC), the laser switches emit a DSR pulse centered at 1551.3 nm. The duration of the DSR could broaden from 17.4 ns to the cavity round trip time with increasing the pump power, while keeping the pulse profile and the intensity unaltered. This type of fiber laser may not only facilitate further investigations of the characteristics of NLP and DSR but also serve as a multi-functional optical source for potential applications.

9.
J Headache Pain ; 18(1): 4, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28091819

RESUMEN

Intracranial hypotension, especially spontaneous intracranial hypotension (SIH), is a well-recognized entity associated with cerebrospinal fluid (CSF) leaks, and has being recognized better in resent years, while still woefully inadequate. An increasing number of factors including iatrogenic factors are realized to involve in development and progression of intracranial hypotension. The diagnosis remains difficult due to the various clinical manifestations, some of which are nonspecific and easily to be neglected. Multiple imaging tests are optional in CSF leakage identification while clinicians are still confronted with difficulties when making selection resulting from superiorities and disadvantages of different imaging tests. Treatments for intracranial hypotension are multifarious but evidence is anecdotal. Values of autologous epidural blood patching (EBP), the mainstay of first-line interventional treatment currently, is getting more and more regards while there are no systematic review of its efficacy and risks. Hereby, the purpose of this review was to reveal the present strategy of intracranial hypotension diagnosis and treatment by reviewing literatures, coupled with our experience in clinical work.


Asunto(s)
Hipotensión Intracraneal/diagnóstico , Hipotensión Intracraneal/terapia , Humanos
10.
Microb Cell Fact ; 15(1): 191, 2016 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-27835967

RESUMEN

BACKGROUND: (R)-[3,5-bis(trifluoromethyl)phenyl] ethanol [(R)-3,5-BTPE] is a valuable chiral intermediate for Aprepitant (Emend) and Fosaprepitant (Ivemend). Biocatalyzed asymmetric reduction is a preferred approach to synthesize highly optically active (R)-3,5-BTPE. However, the product concentration and productivity of reported (R)-3,5-BTPE synthetic processes remain unsatisfied. RESULTS: A NADPH-dependent carbonyl reductase from Lactobacillus kefir (LkCR) was discovered by genome mining for reduction of 3,5-bis(trifluoromethyl) acetophenone (3,5-BTAP) into (R)-3,5-BTPE with excellent enantioselectivity. In order to synthesize (R)-3,5-BTPE efficiently, LkCR was coexpressed with glucose dehydrogenase from Bacillus subtilis (BsGDH) for NADPH regeneration in Escherichia coli BL21 (DE3) cells, and the optimal recombinant strain produced 250.3 g/L (R)-3,5-BTPE with 99.9% ee but an unsatisfied productivity of 5.21 g/(L h). Then, four different linker peptides were used for the fusion expression of LkCR and BsGDH in E. coli to regulate catalytic efficiency of the enzymes and improved NADPH-recycling efficiency. Using the best strain (E. coli/pET-BsGDH-ER/K(10 nm)-LkCR), up to 297.3 g/L (R)-3,5-BTPE with enantiopurity >99.9% ee was produced via reduction of as much as 1.2 M of substrate with a 96.7% yield and productivity of 29.7 g/(L h). CONCLUSIONS: Recombinant E. coli/pET-BsGDH-ER/K(10 nm)-LkCR was developed for the bioreduction of 3,5-BTAP to (R)-3,5-BTPE, offered the best results in terms of high product concentration and productivity, demonstrating its great potential in industrial manufacturing of (R)-3,5-BTPE.


Asunto(s)
Aldehído Reductasa/metabolismo , Glucosa 1-Deshidrogenasa/metabolismo , Aldehído Reductasa/genética , Aldo-Ceto Reductasas , Biotransformación , Electroforesis en Gel de Poliacrilamida/métodos , Glucosa 1-Deshidrogenasa/genética , Técnicas de Placa-Clamp , Alcohol Feniletílico/análogos & derivados , Alcohol Feniletílico/metabolismo
11.
Microb Cell Fact ; 15(1): 121, 2016 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-27392695

RESUMEN

BACKGROUND: 2-keto-D-gluconic acid (2KGA) is widely used as a chemical intermediate in the cosmetic, pharmaceutical and environmental industries. Several microbial fermentation processes have been developed for production of 2KGA but these suffer from substrate/product inhibition, byproduct formation and low productivity. In previous work, we showed that 2KGA can be specifically produced from glucose (Glu) or gluconic acid (GA) by resting wild-type Gluconobacter oxydans DSM2003 cells, although substrate concentration was relatively low. In this study, we attempted to improve 2KGA productivity by G. oxydans DSM2003 by overexpressing the ga2dh gene, which encodes the membrane-bound gluconate-2-dehydrogenase enzyme (GA2DH). RESULTS: The ga2dh gene was overexpressed in G. oxydans DSM2003 under the control of three promoters, P tufB , P ga2dh or P ghp0169 , respectively. Among the recombinant strains obtained, G. oxydans_tufB_ga2dh showed a similar growth rate to that of the control strain and displayed the highest specific productivity of 2KGA from GA, which was increased nearly twofold compared with that of the control strain during batch biotransformation. When biocatalysis conditions were optimized, with provision of sufficient oxygen during biotransformation, up to 480 g/L GA was completely utilized over 45 h by resting cells of G. oxydans_tufB_ga2dh and 453.3 g/L 2KGA was produced. A productivity of 10.07 g/L/h and a yield of 95.3 % were obtained. Overexpression of the ga2dh gene also significantly improved the conversion of Glu to 2KGA. Under optimized conditions, 270 g/L Glu was converted to 321 g/L 2KGA over 18 h, with a yield of 99.1 % and a productivity of 17.83 g/L/h. The glucose concentrations during the batch biotransformation and the 2KGA productivities achieved in this study were relatively high compared with the results of previous studies. CONCLUSIONS: This study developed an efficient bacterial strain (G. oxydans_tufB_ga2dh) for the production of 2KGA by overexpressing the ga2dh gene in G. oxydans. Supply of sufficient oxygen enhanced the positive effect of gene overexpression on 2KGA production. Gluconobacter oxydans_tufB_ga2dh is thus a competitive species for use in 2KGA production.


Asunto(s)
Proteínas Bacterianas/genética , Deshidrogenasas de Carbohidratos/genética , Membrana Celular/enzimología , Gluconobacter oxydans/metabolismo , Azúcares Ácidos/metabolismo , Proteínas Bacterianas/metabolismo , Deshidrogenasas de Carbohidratos/metabolismo , Membrana Celular/genética , Fermentación , Regulación Bacteriana de la Expresión Génica , Gluconobacter oxydans/enzimología , Gluconobacter oxydans/genética , Glucosa/metabolismo , Regiones Promotoras Genéticas
12.
Biotechnol Appl Biochem ; 63(4): 465-70, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25989134

RESUMEN

The asymmetric reduction of prochiral carbonyl compounds by NAD(P)H-dependent carbonyl reductases represents a powerful method for the production of optically active alcohols. The stereoselectivity of a series of carbonyl reductases were evaluated toward the reduction of ethyl 2-oxo-4-phenylbutyrate (OPBE). A majority of reductases produced the ethyl (R)-2-hydroxy-4-phenylbutyrate ((R)-HPBE) with low to excellent enantiomeric excess (e.e.), whereas about 30% reductases catalyzed OPBE to form (S)-HPBE. Among them, the carbonyl reductase from Saccharomyces cerevisiae (SeCR) and short-chain dehydrogenase from Gluconobacter oxydans (GoKR) exhibited 100% e.e., yielding the corresponding (R) and (S)-HPBE, respectively. However, the SeCR showed relative higher activity (29.0 U/mg) and affinity (Km of 0.22 mM) than those of GoKR. Docking analysis found that the interaction of OPBE with enzyme-NADPH complex determined the NADPH-provided hydrogen transfer and the configuration of reductive product. These results indicated that the three-dimensional (3D) structure of enzymes controlled the stereoselectivity of the reductive product based on the geometry of the substrate and cofactor.


Asunto(s)
Oxidorreductasas de Alcohol/metabolismo , Simulación del Acoplamiento Molecular , Fenilbutiratos/química , Fenilbutiratos/metabolismo , Oxidorreductasas de Alcohol/química , Biocatálisis , Cinética , Oxidación-Reducción , Conformación Proteica , Saccharomyces cerevisiae/enzimología , Estereoisomerismo , Especificidad por Sustrato
13.
Biotechnol Lett ; 38(9): 1527-34, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27193896

RESUMEN

OBJECTIVES: To characterize a novel ene-reductase from Meyerozyma guilliermondii and achieve the ene-reductase-mediated reduction of activated C=C bonds. RESULTS: The gene encoding an ene-reductase was cloned from M. guilliermondii. Sequence homology analysis showed that MgER shared the maximal amino acid sequence identity of 57 % with OYE2.6 from Scheffersomyces stipitis. MgER showed the highest specific activity at 30 °C and pH 7 (100 mM sodium phosphate buffer), and excellent stereoselectivities were achieved for the reduction of (R)-carvone and ketoisophorone. Under the reaction conditions (30 °C and pH 7.0), 150 mM (R)-carvone could be completely converted to (2R,5R)-dihydrocarvone within 22 h employing purified MgER as catalyst, resulting in a yield of 98.9 % and an optical purity of >99 % d.e. CONCLUSION: MgER was characterized as a novel ene-reductase from yeast and showed great potential for the asymmetric reduction of activated C=C bonds of α,ß-unsaturated compounds.


Asunto(s)
Proteínas Fúngicas/metabolismo , NADPH Deshidrogenasa/metabolismo , Oxidorreductasas/metabolismo , Saccharomycetales/enzimología , Monoterpenos Ciclohexánicos , Monoterpenos/metabolismo , Saccharomycetales/metabolismo
14.
Biotechnol Lett ; 38(7): 1131-8, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27015861

RESUMEN

OBJECTIVES: To investigate the roles of adhS, which encodes the AdhS subunit of membrane-bound alcohol dehydrogenase (mADH) in Gluconobacter oxydans DSM2003, and to rationally improve mADH activity. RESULTS: adhS was identified and overexpressed in G. oxydans DSM2003. Its overexpression promoted the AdhA subunit which serves as the primary dehydrogenase transfer from the periplasmic space to the periplasmic surface of the membrane thereby increasing the amount of active mADH and thus enhancing mADH activity up to 1.96-fold. The increased mADH activity significantly altered product selectivity (glyceric acid/dihydroxyacetone) during glycerol oxidation and increased the glyceric acid production by 7.6-fold. By comparison, overexpression of adhS and adhABS was equally effective in increasing the mADH activity and glyceric acid production. CONCLUSIONS: adhS overexpression effectively improved mADH activity, indicating that for mADH, adhS might be a limiting component. The findings provide a guide for the efficient application of Gluconobacter spp. in hydroxy acid production.


Asunto(s)
Alcohol Deshidrogenasa/metabolismo , Membrana Celular/enzimología , Gluconobacter oxydans/enzimología , Gluconobacter oxydans/metabolismo , Ácidos Glicéricos/metabolismo
15.
World J Surg Oncol ; 13: 293, 2015 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-26438198

RESUMEN

BACKGROUND: The effectiveness of endoscopic submucosal dissection (ESD) has been increasingly reported. However, studies addressing the safety and application value of ESD in elderly patients with early gastric cancer (EGC) were still lacking. This meta-analysis was intended to evaluate the feasibility and safety of ESD in elderly patients with EGC. METHODS: A systematic search was conducted in PubMed, EBSCO, Cochrane Library, EMBASE, and Web of Science. Studies were screened out if data of elderly and non-elderly gastric cancer patients were reported separately. The qualities of included studies were assessed using Newcastle-Ottawa Quality Assessment Scale. The pooled odd ratios (ORs) with 95 % confidence intervals (CIs) were calculated. Statistical analysis was conducted using the Review Manager 5.2 (Cochrane Collaboration, Oxford, UK). RESULTS: Nine studies (eight in Japan, one in China), including a total of 30,100 lesions, met the inclusion criteria. The "en bloc" and histological complete resection rates of the elderly and non-elderly groups were similar [OR, 0.98, 95 % CI, 0.56 to 1.71; P = 0.93 and OR, 0.79, 95 % CI, 0.58 to 1.07; P = 0.13, respectively]. As for procedure-related complications, similar perforation rates [OR, 1.19, 95 % CI, 0.94 to 1.51; P = 0.15], and bleeding rates [OR, 1.13, 95 % CI, 0.83 to 1.56); P = 0.43] between the elderly and non-elderly groups were observed. Whereas, the elderly patients had a higher procedure-related pneumonia rate compared with non-elderly ones [OR, 2.18, 95 % CI, 1.55 to 3.08; P < 0.01]. CONCLUSIONS: The ESD procedure appears to be a safe technique in elderly patients with EGC while appropriate approach should be taken to avoid procedure-related pneumonia.


Asunto(s)
Disección , Gastroscopía , Neoplasias Gástricas/patología , Neoplasias Gástricas/cirugía , Factores de Edad , Anciano , Mucosa Gástrica/patología , Mucosa Gástrica/cirugía , Humanos , Resultado del Tratamiento
16.
Bioprocess Biosyst Eng ; 38(12): 2487-95, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26481922

RESUMEN

In this work, a two-step process was developed for the production of 3-hydroxypropionic acid from glycerol. In the first step, glycerol was converted to 1,3-propanediol by Klebsiella pneumonia. In the second step, the 1,3-propanediol was converted into 3-hydroxypropionic acid by Gluconobacter oxydans. In a 7.0 L bioreactor, the whole process took 54 h, consumed 480 g glycerol and produced 242 g 3-hydroxypropionic acid. The conversion rate of glycerol to 3-hydroxypropionic acid was 50.4 % (g g(-1)). The final concentration of 3-hydroxypropionic acid arrived 60.5 g L(-1). The process was effective for 3-HP production from glycerol and it might provide a new approach to the biosynthesis of 3-HP from a cheap starting material. Moreover, in this paper, it was first reported that the by-product of 3-hydroxypropionic acid production from 1,3-propandeiol was acrylic acid.


Asunto(s)
Gluconobacter oxydans/metabolismo , Glicerol/metabolismo , Klebsiella pneumoniae/metabolismo , Ácido Láctico/análogos & derivados , Reactores Biológicos , Ácido Láctico/biosíntesis
17.
Antonie Van Leeuwenhoek ; 106(5): 1049-60, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25199563

RESUMEN

Using enrichment procedures, a lipolytic strain was isolated from a stinky tofu brine and was identified as Bacillus amyloliquefaciens (named B. amyloliquefaciens Nsic-8) by morphological, physiological, biochemical tests and 16S rDNA sequence analysis. Meanwhile, the key enzyme gene (named lip BA) involved in ester metabolism was obtained from Nsic-8 with the assistance of homology analysis. The novel gene has an open reading frame of 645 bp, and encodes a 214-amino-acid lipase (LipBA). The deduced amino acid sequence shows the highest identity with the lipase from B. amyloliquefaciens IT-45 (NCBI database) and belongs to the family of triacylglycerol lipase (EC 3.1.1.3). The lipase gene was expressed in Escherichia coli BL21(DE3) using plasmid pET-28a. The enzyme activity and specific activity were 250 ± 16 U/ml and 1750 ± 153 U/mg, respectively. The optimum pH and temperature of the recombinant enzyme were 9.0 and 40 °C respectively. LipBA showed much higher stability under alkaline conditions and was stable at pH 7.0-11.0. The Km and Vmax values of purified LipBA using 4-nitrophenyl palmitate as the substrate were 1.04 ± 0.06 mM and 119.05 ± 7.16 µmol/(ml min), respectively. After purification, recombinant lipase was immobilized with the optimal conditions (immobilization time 3 h at 30 °C, with 92 % enzyme recovery) and the immobilized enzyme was applied in biodiesel production. This is the first report of the lipase activity and lipase gene obtained from B. amyloliquefaciens (including wild strain and recombinant strain) and the recombinant LipBA with the detailed enzymatic properties. Also the preliminary study of the transesterification shows the potential value in biodiesel production applications.


Asunto(s)
Bacillus/enzimología , Biocombustibles , Enzimas Inmovilizadas/metabolismo , Lipasa/metabolismo , Alimentos de Soja/microbiología , Bacillus/genética , Bacillus/aislamiento & purificación , Clonación Molecular , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Estabilidad de Enzimas , Enzimas Inmovilizadas/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Concentración de Iones de Hidrógeno , Cinética , Lipasa/genética , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , Sales (Química) , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Temperatura
18.
Biosci Biotechnol Biochem ; 78(8): 1350-6, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25130736

RESUMEN

The versatile carbonyl reductases from Gluconobacter oxydans in the enantioselective reduction of ketones to the corresponding alcohols were exploited by genome search approach. All purified enzymes showed activities toward the tested ketoesters with different activities. In the reduction of 4-phenyl-2-butanone with in situ NAD(P)H regeneration system, (S)-alcohol was obtained with an e.e. of up to 100% catalyzed by Gox0644. Under the same experimental condition, all enzymes catalyzed ethyl 4-chloroacetoacetate to give chiral products with an excellent e.e. of up to 99%, except Gox0644. Gox2036 had a strict requirement for NADH as the cofactor and showed excellent enantiospecificity in the synthesis of ethyl (R)-4-chloro-3-hydroxybutanoate. For the reduction of ethyl 2-oxo-4-phenylbutyrate, excellent e.e. (>99%) and high conversion (93.1%) were obtained by Gox0525, whereas the other enzymes showed relatively lower e.e. and conversions. Among them, Gox2036 and Gox0525 showed potentials in the synthesis of chiral alcohols as useful biocatalysts.


Asunto(s)
Oxidorreductasas de Alcohol/genética , Oxidorreductasas de Alcohol/metabolismo , Genómica , Gluconobacter oxydans/enzimología , Gluconobacter oxydans/genética , Cetonas/química , Cetonas/metabolismo , Oxidorreductasas de Alcohol/química , Secuencia de Aminoácidos , Coenzimas/metabolismo , Regulación Bacteriana de la Expresión Génica , Datos de Secuencia Molecular , Oxidación-Reducción , Análisis de Secuencia , Estereoisomerismo , Especificidad por Sustrato
19.
Sheng Wu Gong Cheng Xue Bao ; 40(3): 943-952, 2024 Mar 25.
Artículo en Zh | MEDLINE | ID: mdl-38545989

RESUMEN

The biotechnology industry is a strategic emerging industry in our country, holding a crucial position in the national economy. The training of innovative high-quality professionals carries immense significance. As the cornerstone course in biotechnology, "Enzyme Engineering" directly impacts the students' caliber and industry development. This course aims to address pertinent issues present in the current curriculum delivery, such as inadequately optimized content, excessive dependency on textbooks, and reliance on monotonous teaching methods. By adjusting the course outline, updating the case material repository, and engaging students' enthusiasm, we developed a three-dimensional approach to instruct. This approach included a blend of online and offline components, interactive teaching through the flipped classroom methodology, heuristic teaching using problem-based learning (PBL) mode, and topic teaching via case studies. We also improved the assessment mechanism to stimulate students' enthusiasm for learning nurture their innovation capabilities. Our objective was to foster high-quality professionals with a robust foundation and practical expertise. Through teaching exploration and practice, we have witnessed significant improvement in both teaching efficacy and students' engineering practice and innovation abilities.


Asunto(s)
Curriculum , Aprendizaje Basado en Problemas , Humanos , Estudiantes , Aprendizaje , Biotecnología
20.
Heliyon ; 10(10): e31105, 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38779019

RESUMEN

Managing severe chronic pain is a challenging task, given the limited effectiveness of available pharmacological and non-pharmacological treatments. This issue continues to be a significant public health concern, requiring a substantial therapeutic response. Ziconotide, a synthetic peptide initially isolated from Conus magus in 1982 and approved by the US Food and Drug Administration and the European Medicines Agency in 2004, is the first-line intrathecal method for individuals experiencing severe chronic pain refractory to other therapeutic measures. Ziconotide produces powerful analgesia by blocking N-type calcium channels in the spinal cord, which inhibits the release of pain-relevant neurotransmitters from the central terminals of primary afferent neurons. However, despite possessing many favorable qualities, including the absence of tolerance development, respiratory depression, and withdrawal symptoms (largely due to the absence of a G-protein mediation mechanism), ziconotide's application is limited due to factors such as intrathecal administration and a narrow therapeutic window resulting from significant dose-related undesired effects of the central nervous system. This review aims to provide a comprehensive and clinically relevant summary of the literatures concerning the pharmacokinetics and metabolism of intrathecal ziconotide. It will also describe strategies intended to enhance clinical efficacy while reducing the incidence of side effects. Additionally, the review will explore the current efforts to refine the structure of ziconotide for better clinical outcomes. Lastly, it will prospect potential developments in the new class of selective N-type voltage-sensitive calcium-channel blockers.

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