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1.
Front Neurol ; 15: 1423956, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38988601

RESUMEN

Purpose: How cortical functional reorganization occurs after hearing loss in preschool children with congenital sensorineural hearing loss (CSNHL) is poorly understood. Therefore, we used resting-state functional MRI (rs-fMRI) to explore the characteristics of cortical reorganization in these patents. Methods: Sixty-three preschool children with CSNHL and 32 healthy controls (HCs) were recruited, and the Categories of Auditory Performance (CAP) scores were determined at the 6-month follow-up after cochlear implantation (CI). First, rs-fMRI data were preprocessed, and amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) were calculated. Second, whole-brain functional connectivity (FC) analysis was performed using bilateral primary auditory cortex as seed points. Finally, Spearman correlation analysis was performed between the differential ALFF, ReHo and FC values and the CAP score. Results: ALFF analysis showed that preschool children with CSNHL had lower ALFF values in the bilateral prefrontal cortex and superior temporal gyrus than HCs, but higher ALFF values in the bilateral thalamus and calcarine gyrus. And correlation analysis showed that some abnormal brain regions were weak negatively correlated with CAP score (p < 0.05). The ReHo values in the bilateral superior temporal gyrus, part of the prefrontal cortex and left insular gyrus were lower, whereas ReHo values in the bilateral thalamus, right caudate nucleus and right precentral gyrus were higher, in children with CSNHL than HCs. However, there was no correlation between ReHo values and the CAP scores (p < 0.05). Using primary auditory cortex (PAC) as seed-based FC further analysis revealed enhanced FC in the visual cortex, proprioceptive cortex and motor cortex. And there were weak negative correlations between the FC values in the bilateral superior temporal gyrus, occipital lobe, left postcentral gyrus and right thalamus were weakly negatively correlated and the CAP score (p < 0.05). Conclusion: After auditory deprivation in preschool children with CSNHL, the local functions of auditory cortex, visual cortex, prefrontal cortex and somatic motor cortex are changed, and the prefrontal cortex plays a regulatory role in this process. There is functional reorganization or compensation between children's hearing and these areas, which may not be conducive to auditory language recovery after CI in deaf children.

2.
Child Abuse Negl ; 129: 105642, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35509141

RESUMEN

BACKGROUND: Chinese parents and students, especially senior high school students, attach great importance to academic performance. Some studies have confirmed that childhood neglect is related to academic performance. However, the internal mechanism is relatively underexplored. OBJECTIVE: Guided by life course theory and bioecological theory, this study examined the relationship between childhood neglect and academic performance using a serial mediation model that included belief in a just world (PBJW) and academic resilience as hypothesized mediators. METHODS: A sample of 614 tenth grade students (297 males and 307 females, and 10 who did not report their sex; Mage = 15.75 years old, SD = 0.71 years old) completed questionnaires regarding demographics, childhood neglect, PBJW, academic resilience, and academic performance. RESULTS: After demographic covariates were controlled for, the results revealed that: (a) childhood neglect was negatively associated with academic performance; (b) PBJW and academic resilience mediated the link between childhood neglect and academic performance in a parallel fashion; and (c) PBJW and academic resilience also mediated the link between childhood neglect and academic performance in a sequential fashion. CONCLUSIONS: Childhood neglect is negatively related to adolescent academic performance, and the relation is mediated by PBJW and academic resilience both parallelly and sequentially.


Asunto(s)
Rendimiento Académico , Maltrato a los Niños , Adolescente , Niño , China/epidemiología , Femenino , Humanos , Lactante , Masculino , Padres , Estudiantes
3.
Food Chem ; 197 Pt B: 1292-300, 2016 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-26675871

RESUMEN

Nowadays, food industry is facing challenges in preserving better quality of fruit and vegetable products after processing. Recently, many attentions have been drawn to ginger rhizome processing due to its numerous health promoting properties. In our study, ginger rhizome slices were subjected to air-drying (AD), freeze drying (FD), infrared drying (IR), microwave drying (MD) and intermittent microwave & convective drying (IM&CD). Quality attributes of the dried samples were compared in terms of volatile compounds, 6, 8, 10-gingerols, 6-shogaol, antioxidant activities and microstructure. Results showed that AD and IR were good drying methods to preserve volatiles. FD, IR and IM&CD led to higher retention of gingerols, TPC, TFC and better antioxidant activities. However, FD and IR had relative high energy consumption and drying time. Therefore, considering about the quality retention and energy consumption, IM&CD would be very promising for thermo sensitive material.


Asunto(s)
Antioxidantes/farmacología , Extractos Vegetales/farmacología , Zingiber officinale/química , Antioxidantes/química , Catecoles/análisis , Alcoholes Grasos/análisis , Flavonoides/análisis , Liofilización/métodos , Zingiber officinale/ultraestructura , Humanos , Microondas , Análisis de Componente Principal , Volatilización
4.
Food Sci Biotechnol ; 25(1): 137-143, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-30263249

RESUMEN

Changes in antioxidant activities, phenolic contents, cyclic nucleotides, and volatiles of jujube after dehydration using freeze-drying (FD), air drying (AD), sun drying (SD), and microwave drying (MD) were investigated. All dehydration methods caused a decrease in antioxidant activities, aldehyde, acid, and alkane contents. Esters were increased by the dehydration. FD was superior to other dehydration methods for retention of total phenolics, total flavonoids, and antioxidant activities. MD caused an increase of catechin and epichtechin levels. Although AD, MD, and SD caused declines in cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) contents, AD at 50oC was a good choice to obtain jujubes with high levels of cAMP and cGMP. Theoretical fundamentals for selection of suitable drying techniques to minimize the negative effects caused by dehydration and for meeting production requirements are provided.

5.
J Sci Food Agric ; 93(6): 1404-11, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23400926

RESUMEN

BACKGROUND: The anthocyanins of Kyoho grape juice-making pomace, Cabernet Sauvignon grape winemaking pomace and their fresh skin were identified and quantified by high-performance liquid chromatography-tandem mass spectrometry, and the influence of processing on the anthocyanin profiles was investigated. RESULTS: Twenty-three and 16 anthocyanins were found in fresh skin of Kyoho and Cabernet Sauvignon grapes, respectively. Malvidin 3-(trans)-coumaroyl-5-diglucoside and malvidin 3-glucoside were the most abundant anthocyanin in fresh skin of Kyoho and Cabernet Sauvignon grapes, respectively. The cis and trans isomers of malvidin 3-coumaroyl-5-diglucoside are reported in Kyoho grape for the first time. In addition, the anthocyanin content of juice-making pomace of Kyoho grapes and winemaking pomace of Cabernet Sauvignon grapes was significantly lower than the fresh skin samples (p < 0.05). The percentage variation of non-acylated anthocyanins was lower than that of acylated anthocyanins in all pomace samples. CONCLUSION: Kyoho grape and Cabernet Sauvignon grape showed distinctive anthocyanin profiles. Juice-making pomace is a better source of anthocyanins for use in functional foods than winemaking pomace.


Asunto(s)
Antocianinas/análisis , Bebidas/análisis , Manipulación de Alimentos/métodos , Frutas/química , Vitis/química , Acilación , Dieta , Glucósidos/análisis , Humanos , Especificidad de la Especie , Vitis/clasificación , Vino/análisis
6.
Int J Food Microbiol ; 142(1-2): 180-4, 2010 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-20650536

RESUMEN

This study investigated the inactivation of total aerobic bacteria (TAB), lactic acid bacteria (LAB), yeasts in sour Chinese cabbage (SCC) treated by high hydrostatic pressure (HHP). The pressure level ranged from 200 to 600 MPa and the treatment time were 10-30 min. All samples were stored at 4, 27 and 37 degrees C for 90 days. The pressure level of 200 MPa had no significant impact on these microorganisms. The counts of TAB were significantly reduced by 2.7-4.0 log(10)CFU/g at 400 MPa and 4.2-4.5 log(10)CFU/g at 600 MPa from 6.2 log(10)CFU/g; the counts of LAB were also reduced by 2.4-4.3 log(10)CFU/g at 400 MPa from 7.0 log(10)CFU/g and LAB was completely inactivated at 600 MPa; the counts of yeasts were reduced by 1.5-2.0 log(10)CFU/g at 400 and 600 MPa from 4.2 log(10)CFU/g. Storage temperatures significantly influenced the microbial proliferation in HHP-treated SCC depending on the pressure levels. The surviving TAB and LAB at 400 MPa equaled initial counts after 15-day storage at 27 and 37 degrees C, whereas they were inhibited at 4 degrees C up to 60 days. The surviving TAB at 600 MPa did not grow. Yeasts at 400 and 600 MPa decreased below detectable level after 2 days at all the three storage temperatures. From the microbial safety point of view, the result indicated that HHP at 600 MPa could be used as an alternative preservation method for SCC.


Asunto(s)
Bacterias/crecimiento & desarrollo , Brassica/crecimiento & desarrollo , Conservación de Alimentos/métodos , Levaduras/crecimiento & desarrollo , Microbiología de Alimentos , Presión Hidrostática , Viabilidad Microbiana
7.
Bioresour Technol ; 101(18): 7162-8, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20418098

RESUMEN

The extraction kinetics of anthocyanins from red cabbage using high pressure CO(2) (HPCD) against conventional acidified water (CAW) was investigated. The HPCD time, temperature, pressure and volume ratio of solid-liquid mixture vs. pressurized CO(2) (R((S+L)/G)) exhibited important roles on the extraction kinetics of anthocyanins. The extraction kinetics showed two phases, the yield increased with increasing the time in the first phase, the yield defined as steady-state yield (y(*)) was constant in the second phase. The y(*) of anthocyanins using HPCD increased with higher temperature, higher pressure and lower R((S+L)/G). The general mass transfer model with higher regression coefficients (R(2)>0.97) fitted the kinetic data better than the Fick's second law diffusion model. As compared with CAW, the time (t(*)) to reach the y(*) of anthocyanins using HPCD was reduced by half while its corresponding overall volumetric mass transfer coefficients k(L)xa from the general mass transfer model increased by two folds.


Asunto(s)
Antocianinas/aislamiento & purificación , Brassica/química , Dióxido de Carbono/química , Cromatografía con Fluido Supercrítico/métodos , Extractos Vegetales/aislamiento & purificación , Presión
8.
Int J Food Microbiol ; 139(3): 177-81, 2010 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-20338657

RESUMEN

In this paper, the ultrasonic inactivation efficacy of Alicyclobacillus acidiphilus DSM14558(T) and Alicyclobacillus acidoterrestris DSM 3922(T) inoculated into apple juice was investigated at power level from 200 to 600 W for treatment time from 1 to 30 min. The survival ratio of A. acidiphilus DSM14558(T) and A. acidoterrestris DSM 3922(T) decreased with the time of exposure to ultrasounds and with their power. Weibull distribution function, log-logistic model, modified Gompertz equation and biphasic linear model were used to describe the experimental data and the fitness of the models was assessed by the adjusted correlation coefficient (adj-R(2)) and the root mean square error (RMSE). The results showed that, for A. acidiphilus DSM14558(T), the Weibull distribution function described well the characteristic of ultrasonic inactivation, while for A. acidoterrestris DSM 3922(T), the adequate one was the biphasic linear model. Alicyclobacilli had a much higher resistance to ultrasonic treatments in apple juice than in buffer, which indicated that the resistance of alicyclobacilli to ultrasound varied significantly depending on their environment; A. acidoterrestris DSM 3922(T), with the greatest microbial reduction of 4.56 log cycles at 600 W for 30 min, seemed more sensitive to ultrasonic treatments than A. acidiphilus DSM14558(T).


Asunto(s)
Alicyclobacillus/crecimiento & desarrollo , Bebidas/microbiología , Microbiología de Alimentos , Malus/microbiología , Ultrasonido , Contaminación de Alimentos/prevención & control , Modelos Lineales , Viabilidad Microbiana , Modelos Teóricos
9.
Guang Pu Xue Yu Guang Pu Fen Xi ; 29(1): 259-62, 2009 Jan.
Artículo en Chino | MEDLINE | ID: mdl-19385253

RESUMEN

A study was carried out on the contents of mineral elements such as K, Ca, Na, and Mg in seven different orange varieties, namely Pineapple orange, Hamlin, Trovita, Jincheng, 1,232 Tangor, Olinda Valencia and Delta Valencia, by flame atomic absorption spectrometry. The results indicated that the content sequence of different nutritional elements was K > Mg > Ca > Na, with a range of 1,233.75-1,866.23, 77.51-167.15, 49.32-125.29 and 1.22-9.26 mg x L(-1) respectively. The range scale of the four elements was largely consistent with the reference value of AIJN (Association of the Industry of Juices and Nectars from Fruits and Vegetables of the European Union). The samples can be clustered into 2 groups by factor analysis, and lower Na content would be the characteristic of the Valencia varieties. All these data would offer important information for orange juice adulteration determination and quality evaluation.


Asunto(s)
Citrus sinensis/química , Frutas/química , Minerales/análisis , Espectrofotometría Atómica/métodos , Calcio/análisis , Cromatografía Líquida de Alta Presión , Citrus sinensis/clasificación , Glucosa/análisis , Magnesio/análisis , Manganeso/análisis , Sodio/análisis
10.
J Agric Food Chem ; 55(14): 5429-35, 2007 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-17579424

RESUMEN

In this study, a rapid and sensitive method to determine the flavor precursors was established on the basis of modified Kubec's gas chromatography (GC) method. For the new method, the interference of halogen was removed by adding borohydride that replaced halide as a reducing reagent, and the analysis was completed within 25 min for the determination of S-alk(en)yl-L-cysteine sulfoxides (ACSOs). In comparison with the results of high-performance liquid chromatography (HPLC), the modified GC method is much better in the separation and detection of ACSOs in yellow onion bulbs than the original method. A small amount of 2-propenyl-L-cysteine sulfoxides (2-PeCSO) was detected with the modified GC method, and propyl-L-cysteine sulfoxides (PrCSO) were not detected. The results of GC determination indicated that 2-PeCSO probably was the hydrolysate of a byproduct or an isomer of gamma-glumtyl-1-propenyl-L-cysteine sulfoxides in biosynthesis process.


Asunto(s)
Cisteína/análogos & derivados , Cebollas/química , Sulfóxidos/análisis , Cromatografía de Gases/métodos , Cromatografía Líquida de Alta Presión , Cisteína/análisis , Raíces de Plantas/química , Gusto
11.
Ultrason Sonochem ; 14(6): 767-78, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17321780

RESUMEN

Anthocyanins (Acys) are naturally occurring compounds that impart color to fruit, vegetables and plants. The extraction of Acys from red raspberry (Rubus idaeus L. var. Heritage) by ultrasound-assisted process (UAP) was studied. A central composite rotate design (CCRD) was used to obtain the optimal conditions of ultrasound-assisted extraction (UAE), and the effects of operating conditions, such as the ratio of solvents to materials, ultrasonic power and extraction time, on the extraction yield of Acys were studied through response surface methodology (RSM). The optimized conditions of UAE were as follows: ratio of solvents to materials was 4:1 (ml/g), extraction time was 200s, and ultrasonic power was 400 W. Under these conditions 34.5 mg of Acys from 100g of fresh fruits (T(Acy), expressed as cyanidin-3-glucoside), approximately 78.13% of the total red pigments, could be obtained by UAE. The Acys compositions of extracts were identified by high-performance liquid chromatography-mass spectrometry (HPLC-MS), 12 kinds of Acys had been detected and eight kinds of Acys were characterized. Result indicated that cyanidin-3-sophoroside, cyanidin-3-(2(G)-glucosylrutinoside), cyanidin-3-sambubioside, cyanidin-3-rutinoside, cyanidin-3-xylosylrutinoside, cyanidin-3-(2(G)-glucosylrutinoside), and cyanidin-3-rutinoside were main components in extracts. In addition, in comparison with the conventional solvent extraction, UAE is more efficient and rapid to extract Acys from red raspberry, due to the strong disruption of fruit tissue structure under ultrasonic acoustic cavitation, which had been observed with the scanning electron microscopy (SEM). However, the Acys compositions in extracts by both methods were similar, which were investigated using HPLC profile.


Asunto(s)
Antocianinas/química , Antocianinas/aislamiento & purificación , Cromatografía Líquida de Alta Presión/métodos , Frutas/química , Espectrometría de Masas/métodos , Rosaceae/química , Sonicación , Extractos Vegetales/aislamiento & purificación , Extracción en Fase Sólida/métodos
12.
J Agric Food Chem ; 54(21): 8103-7, 2006 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-17032016

RESUMEN

Immersion of intact aged garlic (Allium sativum) cloves in a series of 5% weak organic monocarboxylate solutions (pH 2.0) resulted in green color formation. No color was formed upon treatment with other weak organic acids, such as citric and malic acids, and the inorganic hydrochloric acid under the same conditions. To understand the significance of monocarboxylic acids and their differing function from that of other acids, acetic acid was compared with organic acids citric and malic and the inorganic hydrochloric acid. The effects of these acids on the permeability of plasma and intracellular membrane of garlic cells were measured by conductivity, light microscopy, and transmission electron microscopy. Except for hydrochloric acid, treatment of garlic with all three organic acids greatly increased the relative conductivity of their respective pickling solutions, indicating that all tested organic acids increased the permeability of plasma membrane. Moreover, a pickling solution containing acetic acid exhibited 1.5-fold higher relative conductivity (approximately 90%) as compared to those (approximately 60%) of both citric and malic acids, implying that exposure of garlic cloves to acetic acid not only changed the permeability of the plasma membrane but also increased the permeability of intracellular membrane. Exposure of garlic to acetic acid led to the production of precipitate along the tonoplast, but no precipitate was formed by citric and malic acids. This indicates that the structure of the tonoplast was damaged by this treatment. Further support for this conclusion comes from results showing that the concentration of thiosulfinates [which are produced only by catalytic conversion of S-alk(en)yl-l-cysteine sulfoxides in cytosol by alliinase located in the vacuole] in the acetic acid pickling solution is 1.3 mg/mL, but almost no thiosulfinates were detected in the pickling solution of citric and malic acids. Thus, all present results suggest that damage of tonoplast by treatment with monocarboxylates such as acetic acid may be the main reason for the greening of garlic.


Asunto(s)
Ácidos Carboxílicos/farmacología , Permeabilidad de la Membrana Celular/efectos de los fármacos , Ajo/ultraestructura , Raíces de Plantas/ultraestructura , Ácido Acético/farmacología , Precipitación Química , Ácido Cítrico/farmacología , Ácido Clorhídrico/farmacología , Malatos/farmacología , Microscopía Electrónica
13.
J Agric Food Chem ; 54(21): 8346-51, 2006 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-17032050

RESUMEN

Both microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) have been widely applied in the extraction of a variety of biologically active compounds including carotenoids due to their lower pollution to environment, high extraction efficiency, lower cost, and shorter extraction time as compared to conventional extraction techniques. However, there are few reports on their effects on the stability of these compounds. In the present study, the stability of (all-E)-astaxanthin, one of the carotenoids, was examined under the action of both ultrasound and microwave. Results showed that microwave induced the isomerization of (all-E)-astaxanthin to its Z analogues, preferentially to (13Z)-astaxanthin as analyzed by HPLC coupled with diode array detection and LC-MS; and the percentage of the isomerization increased with increasing both treatment time and microwave power. In contrast to the microwave, the ultrasound degraded (all-E)-astaxanthin to unidentified colorless compound(s) as suggested by HPLC analysis and UV/vis measurements, and the degradation likewise increased as both treatment time and ultrasonic power increased. The results presented here emphasized that both MAE and UAE techniques should be carefully used in the extraction of unstable compounds such as (all-E)-astaxanthin.


Asunto(s)
Microondas , Ultrasonido , Cromatografía Líquida de Alta Presión , Estabilidad de Medicamentos , Isomerismo , Espectrometría de Masas , Xantófilas/química , Xantófilas/aislamiento & purificación
14.
Sci China C Life Sci ; 49(3): 227-34, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16856491

RESUMEN

Subgroup J Avian leucosis virus (ALV-J) strain NX0101 was inoculated into chicken embryo fibroblasts (CEF) monolayers in 6-well plates. The six wells of CEF inoculated with NX0101 were divided into groups A (without anti-ALV-J serum in the medium) and B (with anti-ALV-J serum in the medium), then viruses from each well of both groups were separately passed in CEF every 6 d and formed their independent passage lineages. For each lineage of both groups, gp85 genes of the viruses in the 10th, 20th and 30th passages were amplified, cloned and sequenced. The sequence data indicated that the homologies of gp85 at aa level between the primary virus and the passed viruses of different passages of 3 lineages in group A were 97.7%-99.7%; and the homologies of gp85 between the primary virus and the passed viruses of different passages of 3 lineages in group B were 93.8%-96.1%. Analysis of the ratios of nonsynonium (NS) vs synonium (S) mutations of nucleic acids demonstrated that NS/S in 3 highly variable (hr-) regions at aa#110-120, aa#141-151 and aa#189-194 of gp85 in 3 lineages of group A were 2 (8/4), 1(3/3) and 1.3 (4/3), however, NS/S in the same 3 hr-regions of group B were 4.1 (13/3), 4.7 (14/3) and 3.3 (11/3). This study is the first demonstration of influence of immune selective pressure on evolution of ALV-J gp85 by specific antibodies under the controlled in vitro experiments.


Asunto(s)
Antígenos Virales/genética , Virus de la Leucosis Aviar/genética , Virus de la Leucosis Aviar/inmunología , Evolución Molecular , Genes Virales , Proteínas del Envoltorio Viral/genética , Proteínas del Envoltorio Viral/inmunología , Animales , Anticuerpos Antivirales , Especificidad de Anticuerpos , Virus de la Leucosis Aviar/clasificación , Virus de la Leucosis Aviar/fisiología , Células Cultivadas , Embrión de Pollo , Mutación , Pruebas de Neutralización , Filogenia , Selección Genética , Replicación Viral
15.
J Agric Food Chem ; 53(24): 9620-3, 2005 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-16302786

RESUMEN

Carotenoids are unstable and susceptible to disruption by environmental factors such as heat, light, and solvents. However, there is little information on the effect of metal ions on stability of carotenoids, especially those essential elements in human nutrition. Astaxanthin is one of the few carotenoids containing four oxygen donors. Usually, these oxygen donors can coordinate with heavy metal ions such as Cu(II) and Fe(III). In the present study, the interaction of trans-astaxanthin with Cu(II) was examined. It was found that Cu(II) markedly induces the conversion of trans-astaxanthin to its cis forms, which mainly consist of 9-cis-astaxanthin and 13-cis-astaxanthin as suggested by UV-visible spectra and HPLC measurements. Increasing either incubation time of Cu(II) and trans-astaxanthin in ethanol or the Cu(II)/astaxanthin ratio results in an increased percentage of cis isomers derived from trans-astaxanthin. All these results provide important information on the effects of dietary factors on the bioavailability and bioactivity of trans-astaxanthin.


Asunto(s)
Cobre/farmacología , Etanol , beta Caroteno/análogos & derivados , Cromatografía Líquida de Alta Presión , Cobre/química , Isomerismo , Espectrofotometría , Xantófilas , beta Caroteno/química
16.
J Agric Food Chem ; 53(18): 7103-7, 2005 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-16131117

RESUMEN

While green discoloration during garlic processing is of a major concern, this greening is desirable and required for the traditional homemade Chinese "Laba" garlic. To obtain insights into the mechanism of color formation, simulation of the greening of "Laba" garlic was carried out in the laboratory by soaking aged garlic in 5% (v/v, pH 2.33) acetic acid solution. After 2 days, the garlic cloves turned green. Up to 4 days, pigment(s) diffused from garlic cloves to the pickling solution. The solution exhibits two maximal absorbances at approximately 440 and approximately 590 nm, corresponding to yellow and blue species, respectively, the combination of which creates the green coloration. With increasing time from 4 to 25 days, the concentration of both yellow and blue species increases at nearly the same rate, while after 25 days, the concentration of the yellow species increases faster than that of the blue species. Interestingly, most thiosulfinates ( approximately 85%) in garlic cloves were converted within 4 days, suggesting that thiosulfinate conversion is proportional to the formation of the pigments. Consistent with this conclusion, alliinase and acetic acid were required for the color formation. UV-vis spectral measurements and pH results suggest that the color formation occurs by two kinds of processes: one enzymatic and the other nonenzymatic. Low pH (2.0-3.0) favors nonenzymatic reactions, while high pH (6.0 or above) is conducive to enzymatic reactions. Thus, the ideal pH for the entire process of garlic greening is between 4.0 and 5.0, which is a compromise of the optimal pH of both the enzymatic and nonenzymatic reactions.


Asunto(s)
Color , Manipulación de Alimentos , Ajo/química , Ácido Acético/química , Liasas de Carbono-Azufre/metabolismo , China , Concentración de Iones de Hidrógeno , Espectrofotometría Ultravioleta , Ácidos Sulfínicos/química
17.
Methods Mol Med ; 116: 103-13, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16000857

RESUMEN

Interferon action against viruses is mediated in part through a ribonucleic acid (RNA) decay pathway known as the 2-5A system. Unusual 5'-triphosphorylated, 2',5'-linked oligoadenylates (2-5A) are produced in mammalian cells by interferon-inducible 2-5A synthetases (OAS) in response to viral double-stranded RNA. 2-5A activates a uniquely regulated endoribonuclease, RNase L, resulting in the cleavage of single-stranded viral and cellular RNAs, thus suppressing viral replication. In addition, RNase L was recently identified as a strong candidate for the hereditary prostate cancer 1 susceptibility allele. RNase L is ubiquitously expressed at basal levels in a wide range of mammalian cell types. Conventional RNase L assays, which can be inconvenient and cumbersome, typically involve cleavage of radioactively labeled RNA species or of endogenous ribosomal RNA. Here we describe a convenient, rapid, nonradioactive, and relatively inexpensive fluorescence resonance energy transfer (FRET) that may be used to accurately measure levels of either 2-5A or RNase L activity with a high degree of specificity and sensitivity. The RNA probe used in the FRET assay was designed based on a region of respiratory syncytial genomic RNA. We demonstrate the utility of our FRET assay with several novel biostable analogs of 2-5A.


Asunto(s)
Nucleótidos de Adenina/metabolismo , Endorribonucleasas/metabolismo , Transferencia Resonante de Energía de Fluorescencia/métodos , Oligorribonucleótidos/metabolismo , 2',5'-Oligoadenilato Sintetasa/genética , 2',5'-Oligoadenilato Sintetasa/metabolismo , Nucleótidos de Adenina/química , Animales , Endorribonucleasas/genética , Activación Enzimática , Oligorribonucleótidos/química , ARN/metabolismo , Sensibilidad y Especificidad
18.
Cancer Res ; 63(20): 6795-801, 2003 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-14583476

RESUMEN

The RNASEL gene, a strong candidate for the hereditary prostate cancer 1 allele (HPC1), encodes a single-stranded specific endoribonuclease involved in the antiviral actions of IFNs. RNase L is activated enzymatically after binding to unusual 5'-phosphorylated, 2',5'-linked oligoadenylates (2-5A). Biostable phosphorothioate analogues of 2-5A were synthesized chemically and used to study the effects of naturally occurring mutations and polymorphisms in RNASEL. The 2-5A analogues induced RNase L activity and caused apoptosis in cultures of late-stage, metastatic human prostate cancer cell lines DU145, PC3, and LNCaP. However, DU145 and PC3 cells were more sensitive to 2-5A than LNCaP cells, which are heterozygous for an inactivating deletion mutation in RNase L. The RNase activities of missense variants of human RNase L were compared after expression in a mouse RNase L(-/-) cell line. Several variants (G59S, I97L, I220V, G296V, S322F, Y529C, and D541E) produced similar levels of RNase L activity as wild-type enzyme. In contrast, the R462Q variant, previously implicated in up to 13% of unselected prostate cancer cases, bound 2-5A at wild-type levels but had a 3-fold decrease in RNase activity. The deficiency in RNase L(R462Q) activity was correlated with a reduction in its ability to dimerize into a catalytically active form. Furthermore, RNase L(R462Q) was deficient in causing apoptosis in response to 2-5A consistent with its possible role in prostate cancer development. Our findings support the notion that RNASEL mutations and some variants allow tumor cells to escape a potent apoptotic pathway.


Asunto(s)
Nucleótidos de Adenina/farmacología , Apoptosis/efectos de los fármacos , Endorribonucleasas/genética , Mutación Missense , Oligorribonucleótidos/farmacología , Neoplasias de la Próstata/enzimología , Apoptosis/genética , Neoplasias Óseas/secundario , Neoplasias Encefálicas/secundario , Línea Celular Tumoral , Dimerización , Activación Enzimática/efectos de los fármacos , Humanos , Metástasis Linfática , Masculino , Neoplasias de la Próstata/tratamiento farmacológico , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/patología
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