Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Biomater Res ; 28: 0058, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39040622

RESUMEN

Stem cell therapy is an attractive approach to bone tissue regeneration in osteoporosis (OP); however, poor cell engraftment and survival within injured tissues limits its success in clinical settings. Nitric oxide (NO) is an important signaling molecule involved in various physiological processes, with emerging evidence supporting its diverse roles in modulating stem cell behavior, including survival, migration, and osteogenic differentiation. To control and enhance osteogenic differentiation of mesenchymal stem cells (MSCs) for OP therapy, we designed a near-infrared (NIR) light-triggered NO-releasing nanoplatform based on upconversion nanoparticles (UCNPs) that converts 808-nm NIR light into visible light, stimulating NO release by light control. We demonstrate that the UCNP nanoplatforms can encapsulate a light-sensitive NO precursor, Roussin's black salt (RBS), through the implementation of a surface mesoporous silica coating. Upon exposure to 808-nm irradiation, NO is triggered by the controlled upconversion of UCNP visible light at the desired time and location. This controlled release mechanism facilitates photoregulated differentiation of MSCs toward osteogenic lineage and avoids thermal effects and phototoxicity on cells, thus offering potential therapeutic applications for treating OP in vivo. Following the induction of osteogenic differentiation, the UCNP nanoplatforms exhibit the capability to serve as nanoprobes for the real-time detection of differentiation through enzymatic digestion and fluorescence recovery of UCNPs, enabling assessment of the therapeutic efficacy of OP treatment. Consequently, these UCNP-based nanoplatforms present a novel approach to control and enhance osteogenic differentiation of MSCs for OP therapy, simultaneously detecting osteogenic differentiation for evaluating treatment effectiveness.

2.
Sci Total Environ ; 947: 174459, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-38964397

RESUMEN

In this study, coal-based solid waste geopolymer mortar (SWCB) was prepared by using granulated ground blast-furnace slag (GGBS) and coal gasification coarse slag (CGCS) as precursors, and soda residue (SR) and phosphogypsum (PG) as activators, with gangue sand (GS) utilized as an inert filler. The corresponding compressive strength, fluidity, ion leaching, and microstructure of the developed SWCB were systematically investigated under varying solid contents, binder-to-sand ratios, and activator ratios. The findings suggest that the incorporation of activators promoted the dissolution of the silicon-aluminum phase in GGBS and CGCS into Al(OH)4-, [SiO(OH)3]-, and [SiO2(OH)2]2-, which could subsequently react with the Ca2+ and SO42- released by PG, forming AFt and C-(A)-S-H, thereby playing a crucial role in enhancing matrix strength. AFt was the predominant hydration product in the early reaction stage. The morphology of the AFt phase evolved from needle-like or filamentous to fine and coarse rods as hydration progressed. Initially, the formation of C-(A)-S-H gel increased with rising activator content before decreasing. The optimal synergy between AFt and C-(A)-S-H was observed at an activator content of 30 %. However, the growth of gypsum crystals was hindered when the activator content surpassed 30 %, resulting in a plate-like or columnar morphology. C-(A)-S-H gel exhibited remarkable adsorption capability towards P atoms attributed to intermolecular Van der Waal's forces, enabling simultaneous physical encapsulation of P atoms, while Cl element immobilization was primarily attributed to the contribution of SiOH sites to Cl adsorption.

3.
Sci Rep ; 14(1): 9060, 2024 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-38643280

RESUMEN

The damping coefficient serves to quantify the energy dissipation in particle collisions and constitutes a crucial parameter in discrete element simulations. Nevertheless, the factors influencing the damping coefficient remain unclear, and the damping coefficients of the majority of materials have not been precisely determined. In this investigation, the damping coefficients of eight representative particles were studied using the acoustic frequency sampling method, and the correlations between these coefficients and collision velocity, material density, and elastic modulus were analyzed. The findings indicate that damping coefficients exhibit insensitivity to velocity in strongly elastic and moderately elastic material particles. Conversely, for weakly elastic material particles, damping coefficients demonstrate an increase with rising velocity. The damping coefficient of metallic particles exhibits a linear relationship with material density and elastic modulus.

4.
Materials (Basel) ; 16(8)2023 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-37110001

RESUMEN

With the wide application of petroleum resources, oil substances have polluted the environment in every link from crude oil extraction to utilization. Cement-based materials are the main materials in civil engineering, and the study of their adsorption capacity for oil pollutants can expand the scope of functional engineering applications of cement-based materials. Based on the research status of the oil-wet mechanism of different kinds of oil-absorbing materials, this paper lists the types of conventional oil-absorbing materials and introduces their application in cement-based materials while outlining the influence of different oil-absorbing materials on the oil-absorbing properties of cement-based composites. The analysis found that 10% Acronal S400F emulsion can reduce the water absorption rate of cement stone by 75% and enhance the oil-absorption rate by 62%. Adding 5% polyethylene glycol can increase the oil-water relative permeability of cement stone to 1.2. The oil-adsorption process is described by kinetic and thermodynamic equations. Two isotherm adsorption models and three adsorption kinetic models are explained, and oil-absorbing materials and adsorption models are matched. The effects of specific surface area, porosity, pore interface, material outer surface, oil-absorption strain, and pore network on the oil-absorption performance of materials are reviewed. It was found that the porosity has the greatest influence on the oil-absorbing performance. When the porosity of the oil-absorbing material increases from 72% to 91%, the oil absorption can increase to 236%. In this paper, by analyzing the research progress of factors affecting oil-absorption performance, ideas for multi-angle design of functional cement-based oil-absorbing materials can be obtained.

5.
Materials (Basel) ; 16(6)2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36984395

RESUMEN

The percolation of the interfacial transition zone (ITZ) is generally regarded as an important factor that may accelerate the penetration of aggressive agents in concrete materials, and its threshold is largely determined by the features of aggregates. In most numerical studies about ITZ percolation, both fine aggregates and coarse aggregates are assumed to be the particles of uniform shape, and their size distributions are generally strung together by a single function, which is quite different from reality. To quantify the ITZ percolation associated with the polydispersity of aggregate shapes and size gradations in a more realistic way, the two-dimensional (2D) meso-scale model of concrete is generated by simplifying coarse aggregates and fine aggregates as polygons and ovals, respectively. Moreover, the size gradations of them are also represented by two separate expressions. By combining these models with percolation theory, the percolation of ITZ in the 2D case is explicitly simulated, and the influence of aggregate shape- and size-diversities on the critical threshold ϕagg,c is studied in detail. Based on the simulated results of ϕagg,c, an empirically analytical expression is further proposed to fast predict the ITZ percolation, and its reliability is verified. The results show that the ITZ thickness, average aggregate fineness, coarse aggregate shape, and fine aggregate shapes are the four main contributing factors to the ITZ percolation. Compared with the existing literature, the proposed model here has a broader range of applications (e.g., mortar, concrete, and other granular systems) in the 2D case and can provide the larger predicted results, which may be closer to reality.

6.
Chemosphere ; 307(Pt 3): 135987, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35970219

RESUMEN

The preparation of geopolymer from alkaline solid waste instead of strong alkali presents the disadvantage of low early strength. However, improving the early mechanical properties of the geopolymer to meet the engineering requirements is challenging. In this paper, the effects of different moulding pressures and curing methods on the properties of red mud-ground granulated blast furnace slag activated by municipal solid waste incineration fly ash (MSWIFA)-carbide slag (CRMG) were studied and evaluated in terms of compressive strength and XRD, FTIR, SEM, and MIP techniques analysis. The results showed that the moulding pressure of 30 MPa could increase the compressive strength at 3 d by 182% and decrease the porosity from 30.28% to 27.38%. These results are attributable to the fact that the moulding pressure causes the particles to be tightly bound and promotes the geopolymerisation reaction. High-temperature (HT) curing could accelerate the hydration reaction and increase the compressive strength at 3 d by 133.7% and 141.6% compared with those obtained by water curing (WC) and room-temperature (RT) curing, respectively. Microscopic analyses showed that HT curing can promote the generation of C-(A)-S-H gel, geopolymer gel and hydrate calcium chloroaluminate (HCC), fill the pores, and increase the structure's compactness. Finally, the proposed method was verified by synthesising geopolymer pavement bricks (GPB), and the compressive strength at 3 d was found to reach 54 MPa under an optimal curing method (moulding pressure of 30 MPa, 90 °C for 12 h). Compared with concrete pavement bricks, GPB presents broad application prospects for saving economic costs and protecting the environment. The results provide a theoretical basis and technical support for the application of CRMG in rapid demoulding projects such as unfired bricks.

7.
Front Oncol ; 11: 752573, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34868959

RESUMEN

An increasing number of studies have shown that circRNAs are closely related to the carcinogenesis and development of prostate cancer (PCa). However, little is known about the effect of the biological functions of circRNAs on the enzalutamide resistance of PCa. Through bioinformatic analysis and experiments, we investigated the expression pattern of circRNAs in enzalutamide-resistant PCa cells. Quantitative real-time PCR was used to detect the expression of circRAB3IP, and plasmids that knock down or overexpress circRAB3IP were used to evaluate its effect on the enzalutamide sensitivity of PCa cells. Mechanistically, we explored the potential regulatory effects of eIF4A3 and LEF1 on the biogenesis of circRAB3IP. Our in vivo and in vitro data indicated that increased expression of circRAB3IP was found in enzalutamide-resistant PCa, and knockdown of circRAB3IP significantly enhanced enzalutamide sensitivity in PCa cells. However, upregulation of circRAB3IP resulted in the opposite effects. Further mechanistic research demonstrated that circRAB3IP could regulate the expression of serum and glucocorticoid-regulated kinase 1 (SGK1) by serving as a sponge that directly targets miR-133a-3p/miR-133b. Then, we showed that circRAB3IP partially exerted its biological functions via SGK1 signaling. Furthermore, we discovered that eIF4A3 and LEF1 might increase circRAB3IP expression in PCa.

8.
J Gen Appl Microbiol ; 65(3): 151-160, 2019 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-30686793

RESUMEN

We created a combined system using duckweed and bacteria to enhance the efficiency of ammonium nitrogen (NH4+-N) and total nitrogen (TN) removal from aquaculture wastewater. Heterotrophic nitrifying bacterium was isolated from a sediment sample at an intensive land-based aquaculture farm. It was identified as Acinetobacter sp. strain A6 based on 16S rRNA gene sequence (accession number MF767879). The NH4+-N removal efficiency of the strain and duckweed in culture media and sampled aquaculture wastewater at 15°C was over 99% without any accumulation of nitrite or nitrate. This was significantly higher than strain A6 or duckweed alone. Interestingly, the presence of NO3- increased NH4+-N removal rate by 35.17%. Strain A6 and duckweed had mutual growth promoting-effects despite the presence of heavy metals and antibiotics stresses. In addition, strain A6 colonized abundantly and possibly formed biofilms in the inner leaves of duckweed, and possessed indoleacetic acid (IAA)- and siderophore-producing characteristics. The mutual growth promotion between strain A6 and duckweed may be the reason for their synergistic action of N removal.


Asunto(s)
Acinetobacter/fisiología , Alismatales/microbiología , Compuestos de Amonio/aislamiento & purificación , Interacciones Microbiota-Huesped/fisiología , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Acinetobacter/clasificación , Alismatales/crecimiento & desarrollo , Acuicultura , Biodegradación Ambiental , Procesos Heterotróficos , Filogenia , Aguas del Alcantarillado/microbiología , Temperatura
9.
Ecotoxicol Environ Saf ; 130: 279-88, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27152658

RESUMEN

Using pig manure (PM) compost as a partial substitute for the conventional chemical fertilizers (CFs) is considered an effective approach in sustainable agricultural systems. This study aimed to analyze the impacts of supplementing CF with organic fertilizers (OFs) manufactured using pig manure as a substrate on the spread of tetracycline resistance genes (TRGs) as well as the community structures and diversities of tetracycline-resistant bacteria (TRB) in bulk and cucumber rhizosphere soils. In this study, three organic fertilizers manufactured using the PM as a substrate, namely fresh PM, common OF, and bio-organic fertilizer (BF), were supplemented with a CF. Composted manures combined with a CF did not significantly increase TRB compared with the CF alone, but PM treatment resulted in the long-term survival of TRB in soil. The use of CF+PM also increased the risk of spreading TRGs in soil. As beneficial microorganisms in BF may function as reservoirs for the spread of antibiotic resistance genes, care should be taken when adding them to the OF matrix. The PM treatment significantly altered the community structures and increased the species diversity of TRB, especially in the rhizosphere soil. BF treatment caused insignificant changes in the community structure of TRB compared with CF treatment, yet it reduced the species diversities of TRB in soil. Thus, the partial use of fresh PM as a substitute for CF could increase the risk of spread of TRGs. Apart from plant growth promotion, BF was a promising fertilizer owing to its potential ability to control TRGs.


Asunto(s)
Bacterias/efectos de los fármacos , Fertilizantes/microbiología , Estiércol/microbiología , Rizosfera , Microbiología del Suelo , Resistencia a la Tetraciclina/genética , Agricultura/métodos , Animales , Antibacterianos/farmacología , Bacterias/genética , Bacterias/aislamiento & purificación , Cucumis sativus , Suelo , Porcinos , Tetraciclina/farmacología
10.
Genome Announc ; 3(1)2015 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-25614565

RESUMEN

Bacillus pumilus strain WP8 is an efficient plant growth-promoting rhizobacterium. Here, we present the complete genome of WP8 and its genes involved in plant growth promotion and biocontrol.

11.
Plant Mol Biol ; 87(1-2): 81-98, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25522837

RESUMEN

Two fructan hydrolases were previously reported to exist in Jerusalem artichoke (Helianthus tuberosus) and one native fructan-ß-fructosidase (1-FEH) was purified to homogeneity by SDS-PAGE, but no corresponding cDNA was cloned. Here, we cloned two full-length 1-FEH cDNA sequences from Jerusalem artichoke, named Ht1-FEH I and Ht1-FEH II, which showed high levels of identity with chicory 1-FEH I and 1-FEH II. Functional characterization of the corresponding recombinant proteins in Pichia pastoris X-33 demonstrated that both Ht1-FEHs had high levels of hydrolase activity towards ß(2,1)-linked fructans, but low or no activity towards ß(2,6)-linked levan and sucrose. Like other plant FEHs, the activities of the recombinant Ht1-FEHs were greatly inhibited by sucrose. Real-time quantitative PCR analysis showed that Ht1-FEH I transcripts accumulated to high levels in the developing leaves and stems of artichoke, whereas the expression levels of Ht1-FEH II increased in tubers during tuber sprouting, which implies that the two Ht1-FEHs play different roles. The levels of both Ht1-FEH I and II transcript were significantly increased in the stems of NaCl-treated plants. NaCl treatment also induced transcription of both Ht1-FEHs in the tubers, while PEG treatments slightly inhibited the expression of Ht1-FEH II in tubers. Analysis of sugar-metabolizing enzyme activities and carbohydrate concentration via HPLC showed that the enzyme activities of 1-FEHs were increased but the fructose content was decreased under NaCl and PEG treatments. Given that FEH hydrolyzes fructan to yield Fru, we discuss possible explanations for the inconsistency between 1-FEH activity and fructan dynamics in artichokes subjected to abiotic stress.


Asunto(s)
Glicósido Hidrolasas/metabolismo , Helianthus/fisiología , Estrés Fisiológico , Secuencia de Aminoácidos , Cromatografía Liquida , ADN Complementario , Electroforesis en Gel de Poliacrilamida , Glicósido Hidrolasas/química , Glicósido Hidrolasas/genética , Helianthus/enzimología , Helianthus/genética , Datos de Secuencia Molecular , Filogenia , Homología de Secuencia de Aminoácido , Especificidad por Sustrato , Espectrometría de Masas en Tándem
12.
J Gen Appl Microbiol ; 59(4): 267-77, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24005176

RESUMEN

According to the traditional view, establishment and maintenance of critical population densities in the rhizosphere was the premise of PGPR to exert growth-promoting effects. In light of the facts that soil bacterial community structures can be changed by some PGPR strains including Bacillus pumilus WP8, we hypothesize that regulation of soil bacterial community structure is one of the plant growth-promoting mechanisms of B. pumilus WP8, rather than depending on high-density cells in soil. In this study, denaturing gradient gel electrophoresis (PCR-DGGE) was performed to evaluate the relationship between changes in soil bacterial community structure and growth-promoting effect on the seedling growth of fava beans (Vicia faba L.) during three successive cultivations. We found that B. pumilus WP8 lacks capacity to reproduce in large enough numbers to survive in bulk soil more than 40 days, yet the bacterial community structures were gradually influenced by inoculation of WP8, especially on dominant populations. Despite WP8 being short-lived, it confers the ability of steadily promoting fava bean seedling growth on soil during the whole growing period for at least 90 days. Pseudomonas chlororaphis RA6, another tested PGPR strain, exists in large numbers for at least 60 days but less than 90 days, whilst giving rise to slight influence on bacterial community structure. In addition, along with the extinction of RA6 cells in bulk soils, the effect of growth promotion disappeared simultaneously. Furthermore, the increment of soil catalase activity from WP8 treatment implied the ability to stimulate soil microbial activity, which may be the reason why the dominant population changed and increased as time passed. Our study suggests that regulation of treated soil bacterial community structure may be another possible action mechanism.


Asunto(s)
Bacillus/crecimiento & desarrollo , Biota , Microbiología del Suelo , Bacillus/metabolismo , Dermatoglifia del ADN , Electroforesis en Gel de Gradiente Desnaturalizante , Pseudomonas/crecimiento & desarrollo , Pseudomonas/metabolismo , Vicia faba/crecimiento & desarrollo
13.
Wei Sheng Wu Xue Bao ; 48(4): 480-5, 2008 Apr.
Artículo en Chino | MEDLINE | ID: mdl-18590233

RESUMEN

OBJECTIVE: We identified a microbial transglutaminase (MTGase) gene from Streptomyces hygroscopicus; cloned and expressed it in Escherichia coli. We also analyzed the active sites sequence of S. hygroscopicus MTGase through homologous sequence comparison. METHODS: Wild-type microbial transglutaminase zymogen (pro-MTGase) was purified from liquid culture of S. hygroscopicus (CCTCC M203062). N-terminal amino acid sequence of this pro-MTGase was determined. According to the N-terminal sequence and the corresponding nucleotide sequence of MTGase from other three Streptomyces species, PCR primers of S. hygroscopicus pro-MTGase were designed and the completed gene of pro-MTGase was amplified and sequenced. The gene was sub-cloned into pET-20b(+) vector downstream pelB signal peptide to construct the expression vector pET/pro-MTG. RESULTS: The nucleotide sequence showed 92% homologue with that of S. platensis and S. caniferus. Rosetta (DE3) pLysS carrying the expression vector was induced with IPTG at 24 and expressed pro-MTGase as extracellular soluble protein. SDS-PAGE showed the expressed recombinant pro-MTGase was about 44 kDa, similar to the wild-type pro-MTGase purified from S. hgroscopicus. Recombinant pro-MTGase was activated with trypsin and the enzyme activity reached to 0.24U/mL. CONCLUSION: This is the first report of the gene encoding microbial pro-transglutaminase from S. hygroscopicus, and also this is the first report of expression extracellular soluble pro-MTGase in E. coli in our country.


Asunto(s)
Precursores Enzimáticos/genética , Escherichia coli/genética , Streptomyces/genética , Transglutaminasas/genética , Secuencia de Aminoácidos , Clonación Molecular , Precursores Enzimáticos/biosíntesis , Precursores Enzimáticos/química , Precursores Enzimáticos/aislamiento & purificación , Expresión Génica/efectos de los fármacos , Vectores Genéticos/genética , Datos de Secuencia Molecular , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Solubilidad , Streptomyces/clasificación , Streptomyces/enzimología , Temperatura , Transglutaminasas/biosíntesis , Transglutaminasas/química , Transglutaminasas/aislamiento & purificación
14.
Plant Physiol ; 147(4): 1874-85, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18562768

RESUMEN

Mature plant cell walls lose their ability to expand and become unresponsive to expansin. This phenomenon is believed to be due to cross-linking of hemicellulose, pectin, or phenolic groups in the wall. By screening various hydrolytic enzymes, we found that pretreatment of nongrowing, heat-inactivated, basal cucumber (Cucumis sativus) hypocotyls with pectin lyase (Pel1) from Aspergillus japonicus could restore reconstituted exogenous expansin-induced extension in mature cell walls in vitro. Recombinant pectate lyase A (PelA) and polygalacturonase (PG) from Aspergillus spp. exhibited similar capacity to Pel1. Pel1, PelA, and PG also enhanced the reconstituted expansin-induced extension of the apical (elongating) segments of cucumber hypocotyls. However, the effective concentrations of PelA and PG for enhancing the reconstituted expansin-induced extension were greater in the apical segments than in the basal segments, whereas Pel1 behaved in the opposite manner. These data are consistent with distribution of more methyl-esterified pectin in cell walls of the apical segments and less esterified pectin in the basal segments. Associated with the degree of esterification of pectin, more calcium was found in cell walls of basal segments compared to apical segments. Pretreatment of the calcium chelator EGTA could also restore mature cell walls' susceptibility to expansin by removing calcium from mature cell walls. Because recombinant pectinases do not hydrolyze other wall polysaccharides, and endoglucanase, xylanase, and protease cannot restore the mature wall's extensibility, we can conclude that the pectin network, especially calcium-pectate bridges, may be the primary factor that determines cucumber hypocotyl mature cell walls' unresponsiveness to expansin.


Asunto(s)
Pared Celular/efectos de los fármacos , Cucumis sativus/efectos de los fármacos , Ácido Egtácico/farmacología , Proteínas Fúngicas/farmacología , Hipocótilo/efectos de los fármacos , Polisacárido Liasas/farmacología , Calcio/análisis , Pared Celular/ultraestructura , Cucumis sativus/crecimiento & desarrollo , Cucumis sativus/ultraestructura , Hipocótilo/crecimiento & desarrollo , Hipocótilo/ultraestructura , Datos de Secuencia Molecular , Pectinas/análisis , Proteínas de Plantas/farmacología , Poligalacturonasa/farmacología
15.
J Agric Food Chem ; 56(9): 3403-8, 2008 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-18380462

RESUMEN

Transglutaminase (TGase) is widely used in the food industry for improving protein properties by catalyzing the cross-linking of proteins. In Streptomyces, TGase is secreted as a zymogen, and an activation process has been observed in liquid culture. However, the activation mechanism remains unclear. In the present study, the TGase activation process in Streptomyces hygroscopicus was investigated by biochemical approaches. In a liquid culture, Pro-TGase was secreted and gradually was converted into active TGase during the growth period; however, in a cell-free system in which cells were removed from the liquid culture, TGase activation stalled unexpectedly. Subsequently, the TGase activation process was found to be inhibited by a TGase-activating protease inhibitor (TAPI). N-Terminal amino acid sequencing and a homology search of the purified TAPI revealed that it is a member of the Streptomyces subtilisin inhibitor (SSI) family. Furthermore, it was found that TAPI (0.1 mg/mL) decreased the surface tension of water from 72 to 60 mJ/m2 within 5 min, suggesting that it possesses surface activity. This is the first report that an SSI member functions as a surfactant protein. On the basis of these findings, a model for TAPI-regulated TGase activation process was proposed. This study provides novel insights into the TGase activation process in Streptomyces.


Asunto(s)
Proteínas Bacterianas/farmacología , Streptomyces/química , Subtilisina/antagonistas & inhibidores , Tensoactivos/farmacología , Transglutaminasas/antagonistas & inhibidores , Activación Enzimática/efectos de los fármacos , Streptomyces/enzimología
16.
Sheng Wu Gong Cheng Xue Bao ; 23(5): 873-7, 2007 Sep.
Artículo en Chino | MEDLINE | ID: mdl-18051868

RESUMEN

Pectin lyases from Aspergillus oryzae and Aspergillus niger are usually used for the production of traditional fermented foods, but these fungi produce less pectinases under natural conditions. The cDNA coding mature Pell (without signal peptide) was amplified from Aspergillus oryzae by RT-PCR. Pell cDNA was cloned into pET-28a ( + ) expression vector, then was transformed into E. coli Turner (DE3) plac I cells to express Pell with 6-His tag. For improving the efficiency of Pell expression in E. coli, the conditions of expressing the Pell in E. coli were optimized. E. coli Turner (DE3) plac I cells with pET-28a ( + )-pell was first cultivated at 37 degrees C, 220 r/min until OD600 reached about 0.8. Then, cultivation broth was added with 0.05-0.1 mmol/L IPTG and continuously incubated at 15 degrees C, at 170 r/min for 60 h for expressing of Pell. The recombinant expressed Pell activity could reach 400 u/mL medium, which is 4000-fold of Pell produced naturally by A. oryzae and superior than known recombinant amount of pectin lyases expressed in different fungi expression systems.


Asunto(s)
Aspergillus oryzae/enzimología , Escherichia coli/metabolismo , Polisacárido Liasas/biosíntesis , Secuencia de Aminoácidos , Aspergillus oryzae/genética , Secuencia de Bases , Escherichia coli/genética , Vectores Genéticos/genética , Datos de Secuencia Molecular , Polisacárido Liasas/genética , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
17.
Sheng Wu Gong Cheng Xue Bao ; 23(1): 101-5, 2007 Jan.
Artículo en Chino | MEDLINE | ID: mdl-17366896

RESUMEN

Pectinases are mainly used in the food industry to clarify fruit juices and wine, improve oil extraction, remove the peel from the citrus fruit, increase the firmness of some fruits and degum fibres. The filamentous fungus Aspergillus oryzae, used for the production of traditional fermented foods, only could produce less pectinases under general conditions. So far only a few of PGs expressed in yeast or E. coli were reported but they did not show higher activity. The cDNA of mature PGA (without signal peptide) was synthesized with specific primers from total RNA of Aspergillus oryzae by RT-PCR. PGA cDNA was ligated into pET-28a( + ) expression vector, creating plasmid pET-28a( + )-pgA. The plasmid pET-28a( + )-pgA was transformed into E. coli Turner (DE3) plac I cells to express PGA heterogeneously. For improving the efficiency of PGA expression in E. coli, the conditions for expression of the PGA in E. coli were optimized. E. coli Turner (DE3) plac I cells with pET-28a( + )-pgA was first cultivated at 37 degrees, 220r/min until OD600nm reached about 0.8. Then, cultivation broth was added with 0.5 mmol/L IPTG and incubated at 15 degrees C, 170r/min for other 24 h for induced-expression of PGA. Our data showed that the activity of recombinant expressed PGA could reach to 70u/mL medium, which is 87.5-fold of the activity of PGA produced in culture of A. oryzae and superior than known recombinant expression amount of PGA reported by other researchers.


Asunto(s)
Aspergillus oryzae/enzimología , Escherichia coli/genética , Proteínas Fúngicas/metabolismo , Poligalacturonasa/metabolismo , Secuencia de Aminoácidos , Aspergillus oryzae/genética , Secuencia de Bases , Biocatálisis , ADN Complementario/genética , Proteínas Fúngicas/genética , Regulación Enzimológica de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Datos de Secuencia Molecular , Plásmidos/genética , Poligalacturonasa/genética , Proteínas Recombinantes/metabolismo , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido Nucleico , Temperatura , Factores de Tiempo
18.
Sheng Wu Gong Cheng Xue Bao ; 20(5): 764-9, 2004 Sep.
Artículo en Chino | MEDLINE | ID: mdl-15974006

RESUMEN

After the cell enters into its programmed cell death, xylanases from grass plants gradually matured through its N-terminal and C-terminal sequence been cut by acid proteases several times. They could not be expressed by conventional protein expression system. Search the GenBank database, xynIII from a mutant of T. reesei QM9414(ATCC26921)was found. It is similar to grass plants' xylanase in their families and structures. It couldn't express in T. reesei QM9414, but its gene exist in genomic DNA as one copy. Through overlap-PCR method, 4 exons of xynIII were cloned, sequenced, spliced, and the whole cDNA of mature xynIII was acquired. The cDNA was inserted into pETBlue-2 vector and transformed into E. coli DE3 pLacI cell. Xyn III could be expressed in the transformed cell under the conditions of 37 degrees C, 1 mmol/L IPTG induced for 3h. Low temperature (15 degrees C), long time(64h) induction(0.2 mmol/L IPTG) could enhance xynIII activity.


Asunto(s)
Endo-1,4-beta Xilanasas/genética , Reacción en Cadena de la Polimerasa/métodos , Trichoderma/genética , Clonación Molecular , ADN Complementario/química , Endo-1,4-beta Xilanasas/metabolismo
19.
Zhonghua Liu Xing Bing Xue Za Zhi ; 24(8): 697-9, 2003 Aug.
Artículo en Chino | MEDLINE | ID: mdl-14521791

RESUMEN

OBJECTIVE: To evaluate the immuno-effects of hepatitis B (HB) vaccination in adults. METHODS: Five groups were sampled by means of cluster sampling, and serum HBsAg, anti-HBs and anti-HBc were tested in every group at people aged from 18 to 50. Recombinant HB vaccine was injected to the ones that HBsAg, anti-HBs and anti-HBc were all negative. Concentration of anti-HBs in serum was tested after one year and three years of vaccination. Immuno-effects of recombinant HB vaccination in adults at different ages and between sexes, were then calculated. RESULTS: Good immuno-effects of recombinant HB vaccination in adults were noticed. After one year and three years of vaccination with 5 micro g recombinant HB vaccine, the anti-HBs positive rates were 82.76%, 70.77% while the serum concentrations of anti-HBs were 55.91 mIU/ml and 35.41 mIU/ml respectively. When 10 micro g was used, the concentrations were 83.74%, 72.22%, 56.89 mIU/ml and 30.29 mIU/ml respectively. The effects did not show significant differences between different doses on 10 micro g and of 5 micro g. Concentration of anti-HBs reduced when time went by. The factors such as age and sex influenced the effects of immunity on recombinant HB vaccination. CONCLUSION: Good immunity could be obtained when recombinant hepatitis B was vaccinated in vulnerable population aged 18 to 50.


Asunto(s)
Vacunas contra Hepatitis B/inmunología , Hepatitis B/prevención & control , Vacunación , Vacunas Sintéticas/inmunología , Adolescente , Adulto , Femenino , Anticuerpos contra la Hepatitis B/sangre , Antígenos del Núcleo de la Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/inmunología , Humanos , Masculino , Persona de Mediana Edad
20.
Yi Chuan ; 24(4): 447-54, 2002 Jul.
Artículo en Chino | MEDLINE | ID: mdl-16135428

RESUMEN

There is a complex- and multi-effect for interdependent survival between intestinal- microorganisms and hosts. The symbiosis or coevolution that results from this effect for interdependent survival is used to reveal the phylogenies of hosts as well as intestinal microorganisms. The symbiosis or coevolution between intestinal microorganisms and hosts has been generated by interactive natural selection occurred between them. The symbiosis information that has been formed by interactive natural selection during a long evolutionary process must be recorded in DNA sequences. According to this point of view,we analyzed the phylogeny of 9 intestinal bacteria genera using their contents in intestines of 8 Cyrinidate species. At the same time,we fetched the 16S rRNA gene DNA sequences of 43 intestinal bacteria species being included in these nine genera of six intestinal families from GeneBank and constructed phylogenetic trees by NJ and MP methods. The NJ tree and MP tree have the same topologic configuration and are identical with the classical phylogenetic tree. Both the trees of 16S rRNA gene separated 43 bacteria species into gram-negative bacteria group and the gram-positive bacteria group,which are the first branches. Each of the first branches (groups) made again 6 subbranches (subgroups) where each subbranch is a family.Especially,the subbranch (subgroup) of enterobacteriaceace made again four small branches as genus taxon. This tree also shows that bacilliform bacterium is distinct from each other in the NJ and MP trees. After all species on the tree are merged,the topological configuration of the unrooted tree of 16S gene is closed to that of the host range unrooted tree.However,the position of bacillus is greatly changed on both the unrooted trees. The difference can be found if we increase the examination level and extend the hosts examed.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...