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1.
Food Chem ; 352: 129358, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33657484

RESUMO

A novel maltoheptaose-palmitate ester (G7-PA) was synthesized and investigated for emulsion properties. First of all, the optimal conditions for lipase-catalyzed G7-PA synthesis, which were 0.2 of the G7/PA molar ratio, 33.5 U of immobilized CALB per 1 g of PA in 10% DMSO, were determined by response surface methodology. G7-PA was compared with the commercial sucrose-PA (S-PA) in terms of emulsion-forming ability and stability at extreme conditions. At the 0.1% surfactant concentration, G7-PA emulsion exhibited a droplet distribution similar to the 0.2% surfactant condition, while S-PA emulsion was quickly destabilized. G7-PA showed better emulsifying properties than the S-PA at the acidic condition (pH 3). Flocculation and phase separation was observed at the S-PA emulsion, but the G7-PA emulsion was stable for 7-day. In thermostability tests, G7-PA and S-PA both were stable up to the boiling temperature. Conclusively, G7-PA exhibits excellent properties as a biosurfactant in O/W emulsion compared with S-PA.


Assuntos
Biocatálise , Emulsificantes/química , Emulsificantes/síntese química , Ésteres/química , Glucanos/química , Glucanos/síntese química , Lipase/metabolismo , Técnicas de Química Sintética
2.
Molecules ; 24(14)2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31311184

RESUMO

Herein, contaminants remaining in distillate and distillers' stillage were quantitatively measured after distillation. After rice bran powder was contaminated with 10 ppm of lead (Pb) and cadmium (Cd) or 0.02-1.27 ppm of five pesticides (terbufos, fenthion, iprobenfos, flutolanil, and ethoprophos) followed by fermentation, single-stage distillation was performed. In the obtained distillate, no Pb or Cd was found, as expected. However, when the pesticides were added as contaminants, trace-0.05 ppm of some pesticides were detected in the distillate, possibly due to the high vapor pressure (e.g., that of ethoprophos) and contamination amount (e.g., that of flutolanil, terbufos, and fenthion). In contrast, none of the contaminating pesticides were observed in the distilled spirits when a fermented liquefaction contaminated with 0.04-4 ppm of six pesticides (fenthion, terbufos, ethoprophos, iprobenfos, oxadiazon, and flutolanil) was distilled using a pilot-plant scale distillation column, indicating that the pesticides hardly migrate to the distilled spirits.


Assuntos
Bebidas Alcoólicas/análise , Contaminação de Alimentos/análise , Oryza/química , Resíduos de Praguicidas/análise , Anilidas/análise , Cádmio/análise , Destilação , Fention/análise , Fermentação , Chumbo/análise , Compostos Organotiofosforados/análise , Projetos Piloto
3.
Carbohydr Polym ; 218: 126-135, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31221313

RESUMO

In this study, maltoheptaose (G7)-based sugar esters were synthesized from maltoheptaose and fatty acids (C10-C16) using a commercial lipase. With the exception of dimethyl sulfoxide (DMSO; 76.4%, w/v), G7 showed only limited solubility in organic solvents. Among the fatty acids, palmitic acid (PA) was the best substrate for G7-based ester formation. G7-PA ester was successfully synthesized as the monoester structure exclusively in 10% DMSO of t-butanol with a 22% conversion yield. NMR and enzymatic analyses of the purified monoester product revealed that the ester bond in the G7 was located at C-6 of the glucose at the reducing end. The G7-PA monoester showed the melting temperature at 56.3 °C that was 6.5 °C lower than that of the free PA and exhibited a different endothermic pattern from the free G7. The G7-PA monoester exhibited excellent emulsifier potential with more even droplet size distribution compared with the commercial sucrose esters for an oil-in-water emulsion system.


Assuntos
Hidrolases de Éster Carboxílico/química , Ésteres/química , Proteínas Fúngicas/química , Glucanos/química , Candida/enzimologia , Emulsificantes/síntese química , Emulsificantes/química , Emulsões , Esterificação , Ésteres/síntese química , Ácidos Graxos/química , Glucanos/síntese química , Solubilidade , Temperatura de Transição
4.
Food Sci Biotechnol ; 28(1): 35-41, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30815292

RESUMO

The product of ferulic acid decarboxylation, 4-vinylguaiacol (4-VG), is an important antioxidant and is reported to have an antioxidant capacity comparable to α-tocopherol. In this study, evaluation on antioxidant capacities of ferulic acid, catechin, and 4-VG was performed when 200 ppm of each compound was added in a 10% O/W emulsion for 50 days. Peroxide value (POV) results of the O/W emulsion containing 4-VG were noteworthy. The POV was 1.9 meq/L of emulsion after 29 days, which was no different to the initial value (day 0). Even when the oxidation was allowed to advance to day 50, the POV remained at 2.2 meq/L of emulsion, representing only a tiny increase relative to the initial value on day 0. 1H-NMR results also showed that the lowest conjugated forms and no aldehydes were detected in emulsion of 4-VG stored for 50 days, proving the excellent antioxidant capacity in the O/W emulsion.

5.
Nutrients ; 11(3)2019 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30901932

RESUMO

In this study, two in vitro digestion models were employed to compare the rate of lipolysis in soybean oil (SBO), pomegranate oil (PGO), a physical blend (PHY, 1:1 molar ratio of SBO:PGO, w/w), and their enzymatically interesterified oil (IO). In the pH-stat digestion model (emulsified oils with bile salts), PGO emulsion containing 74.7% conjugated form of linolenic acid (CLn) showed a significantly lower release rate of free fatty acid (FFA) than the other oil emulsions (p < 0.05). In FFA release rates and oil droplet sizes between PHY and IO emulsions, no significant differences were observed (p > 0.05). In a simulated model of small intestinal digestion, the lipolysis rates of SBO, PGO, PHY, and IO after digestion for 30 min in digestion fluids were 80.4%, 66.5%, 74.8%, and 77.0%, respectively. The rate of lipolysis in PGO was significantly lower than that in SBO (p < 0.05), and the lowest lipolysis rate was observed in the conjugated form of trilinolenoyl glycerol (CLn-CLn-CLn).


Assuntos
Ácidos Graxos/farmacologia , Lipólise/efeitos dos fármacos , Lythraceae , Óleos Vegetais/farmacologia , Óleo de Soja/farmacologia , Ácidos e Sais Biliares , Digestão/efeitos dos fármacos , Emulsões/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Intestino Delgado/metabolismo , Modelos Biológicos , Ácido alfa-Linoleico
6.
Prev Nutr Food Sci ; 21(3): 289-295, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27752506

RESUMO

Curcumin is a flavonoid found in the rhizome of the turmeric plant (Curcuma longa L.) and has recently attracted interest because it has numerous biological functions and therapeutic properties. In the present study, we attempted to incorporate curcumin into medium-chain triglyceride (MCT) nanoemulsions (0.15 wt% curcumin, 10 wt% MCT oil, and 10 wt% emulsifiers) with various emulsifiers [polyoxyethylene (20) sorbitan monolaurate (Tween-20), sorbitan monooleate (SM), and soy lecithin (SL)]. The physicochemical properties of the nanoemulsions including the Ostwald ripening stability were investigated. The initial droplet size was found to be 89.08 nm for the nanoemulsion with 10 wt% Tween-20 (control), and when Tween-20 was partially replaced with SM and SL, the size decreased: 73.43 nm with 4 wt% SM+6 wt% Tween-20 and 67.68 nm with 4 wt% SL+6 wt% Tween-20 (prepared at 15,000 psi). When the nanoemulsions were stored for 28 days at room temperature, the droplet size increased as the storage time increased. The largest increase was observed for the control nanoemulsion, followed by the 4 wt% SL+6 wt% Tween-20 and 4 wt% SM+6 wt% Tween-20 systems. The Turbiscan dispersion stability results strongly supported the relationship between droplet size and storage time. The time-dependent increase in droplet size was attributed to the Ostwald ripening phenomenon. Thus, the Ostwald ripening stability of curcumin-loaded MCT nanoemulsions with Tween-20 was considerably improved by partially replacing the Tween-20 with SM or SL. In addition, curcumin may have acted as an Ostwald ripening inhibitor.

7.
J Food Sci ; 81(1): C35-41, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26641978

RESUMO

Caffeic acid was used to synthesize 4-vinylcatechol (4-VC) by thermal decarboxylation and to prepare caffeic acid phenethyl ester (CAPE) by esterification reaction. The identities of synthesized products were confirmed by (1)H NMR. Antioxidative activities of 4-VC and CAPE were compared with α-tocopherol and BHT in stripped soybean oil at 60 °C under the dark. To evaluate the degrees of oxidation at different concentrations and combinations, peroxide value (PV) and (1)H NMR were performed. From the results of PV, the formation of primary oxidation products (i.e., hydroperoxides) in stripped soybean oil containing 200 ppm CAPE was the slowest. The relative oxidation degree of 200 ppm CAPE (9.5%) was lower than other samples on 9 d. Similar results were obtained by (1)H NMR analysis. After 15 d of storage, levels of conjugated diene forms and aldehydes of 200 ppm CAPE sample (57.3 and 0.9 mmol/mol oil) were also lower than other treatments. In addition, 4-VC and α-tocopherol were found to have a synergistic antioxidant effect.


Assuntos
Antioxidantes/química , Ácidos Cafeicos/química , Catecóis/química , Álcool Feniletílico/análogos & derivados , Óleo de Soja/química , Peróxido de Hidrogênio/química , Oxirredução , Peróxidos/química , Álcool Feniletílico/química , alfa-Tocoferol/análise
8.
J Food Sci ; 80(3): C510-4, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25678328

RESUMO

To compare the oxidative stability between diacylglycerol (DAG) oil and conventional triacylglycerol (TAG) oil (that is, soybean oil), the prepared stripped diacylglycerol oil (SDO) and soybean oil (SSBO) were stored at 60 °C in the dark for 144 h. During storage peroxide values (POVs), contents of aldehydes, unsaturated fatty acids were measured to evaluate the oxidative stabilities of the 2 oils. The results showed the content of C18:2, C18:3, and total unsaturated fatty acid decreased faster in DAG oil than in soybean oil, whereas the decreased rate of C18:1 was similar in 2 oils. Also, both rate constants (K1 and K2) obtained from POV (K1 ) and total aldehydes (K2 ) indicated that DAG oil (K1 = 3.22 mmol/mol FA h(-1) , K2 = 0.023 h(-1)) was oxidized more rapidly than soybean oil (K1 = 2.56 mmol/mol FA h(-1) , K2 = 0.021 h(-1)), which was mainly due to the difference of acylglycerol composition of the 2 oils along with higher C18:3 (9.6%) in SDO than SSBO (5.7%). It is concluded that DAG was more easily oxidized than soybean oil at 60 °C in the dark for 144 h.


Assuntos
Diglicerídeos/análise , Peroxidação de Lipídeos , Óleos/análise , Óleo de Soja/análise , Triglicerídeos/análise , Dieta , Glicerídeos/análise , Humanos , Oxirredução
9.
Food Chem ; 174: 124-31, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25529661

RESUMO

In this study, we have produced a structured lipid with a low ω6/ω3 ratio by lipase-catalysed interesterification with perilla and grape seed oils (1:3, wt/wt). A Ginkgo biloba leaf extract was fractionated in a column packed with HP-20 resin, producing a flavonoid glycoside fraction (FA) and a biflavone fraction (FB). FA exhibited higher antioxidant capacity than FB, showing 58.4 mmol gallic acid equivalent (GAE)/g-of-total-phenol-content, 58.8 mg quercetin equivalent (QUE)/g-of-total-flavonoid-content, 4.5 mmol trolox/g-of-trolox-equivalent antioxidant capacity, 0.14 mg extract/mL-of-free-radical-scavenging-activity (DPPH assay, IC50), and 2.3 mmol Fe2SO4 · 7H2O/g-of-ferric-reducing-antioxidant-power. The oil-in-water emulsion containing the stripped structured lipid as an oil phase with FA exhibited the highest stability and the lowest oil globule diameters (d43 and d32), where the aggregation was unnoticeable by Turbiscan and particle size analyses during 30 days of storage. Furthermore, FA was effective in retarding the oxidation of the emulsions.


Assuntos
Ácidos Graxos Ômega-3/química , Ácidos Graxos Ômega-6/química , Flavonoides/química , Ginkgo biloba/química , Glicosídeos/química , Extratos Vegetais/química , Antioxidantes/química , Emulsões/química , Lipídeos/química , Oxirredução , Fenóis/química
10.
J Food Sci ; 78(1): C43-9, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23278764

RESUMO

UNLABELLED: The desired mix of alpha-linolenic acid (ALA)-enriched structured lipid (SL) and physically blended lipid (PB) was prepared from grape seed oil and perilla oil at a weight ratio of 3:1. The major triacylglycerol species (LnLnL) in PB was drastically increased after interesterification (SL), from 0.5% to 16.8%. After the reaction, the total unsaturated fatty acid at the sn-2 position was decreased from 98.83% in PB to 91.36% in SL. The reduction of vitamin E compounds was also observed. Compared with a PB-based emulsion, SL-based emulsions showed oxidative instability, as assessed by lipid hydroperoxide (LOOH) and 2-thiobarbituric acid-reactive substances (TBARS) values, which was mainly due to the SL which contained less LA, ALA, and ΣUSFA at the sn-2 position and less γ-tocopherol than did PB. PB-, and SL-based emulsions with Ginkgo biloba extract (GBE) which showed significantly lower values of LOOH and TBARS compared to a blank control. GBE was effective in retarding the oxidation of the emulsion by quenching the free radicals in the water phase of the emulsion and inhibiting the formation of primary and secondary oxidation products. These results indicate that GBE could be used as an antioxidant additive for stabilizing ALA-enriched emulsions. PRACTICAL APPLICATION: The results suggest the possibility to supplement Ginkgo biloba extract in alpha linolenic acid-enriched structured lipid-based emulsions which would increase the therapeutic value and enhance the antioxidant potential of the emulsions.


Assuntos
Antioxidantes/farmacologia , Ginkgo biloba/química , Extratos Vegetais/análise , Ácido alfa-Linoleico/análise , Antioxidantes/análise , Emulsões , Gorduras/química , Peróxidos Lipídicos/análise , Oxirredução , Óleos Vegetais/análise , Óleos Vegetais/química , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Triglicerídeos/análise , Ácido alfa-Linoleico/química , gama-Tocoferol/análise
11.
J Food Sci ; 78(1): C17-24, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23278855

RESUMO

UNLABELLED: Modified butterfats (MBFs) were produced by lipase-catalyzed interesterification with 2 substrate blends (6:6:8 and 4:6:10, by weight) of anhydrous butterfat (ABF), palm stearin, and flaxseed oil in a stirred-batch type reactor after short path distillation. The 6:6:8 and 4:6:10 MBF contained 21.7% and 26.5%α-linolenic acid, respectively. Total saturated fatty acids of the MBFs ranged from 41.4% to 47.4%. The cholesterol contents of the 6:6:8 and 4:6:10 MBFs were 21.0 and 12.1 mg/100 g, respectively. In addition, the melting points of the 6:6:8 and 4:6:10 MBFs were 32 °C and 31 °C, respectively. After preparation of recombined milks (oil-in-water emulsions) with MBFs, the stability of emulsions prepared with the MBFs (6:6:8 and 4:6:10) was compared to those with ABF during 10-d storage at 30 °C. Skim milk powder (containing 1% protein) was added to prepare emulsions as an emulsifier. Microstructures of emulsions freshly prepared with the ABF and the MBFs consisted of uniform fat globules with no flocculation during 10-d storage. With respect to fat globule size distribution, the volume-surface mean droplet diameter (d(32)) of the 6:6:8 and 4:6:10 MBF emulsions ranged between 0.33 and 0.34 µm, which was similar to the distribution in ABF emulsion. PRACTICAL APPLICATION: Milk, an expensive dairy food, has been widely used in various milk-derived food products. Modified butterfats (MBFs) contain α-linolenic acid as an essential fatty acid. Emulsion stability of recombined milks (oil-in-water emulsions) with MBFs was similar to that in anhydrous butterfat emulsion during 10-d storage. They may be a promising alternative for reconstituted milks to use in processed milk-based products.


Assuntos
Manipulação de Alimentos/métodos , Leite/química , Ácido alfa-Linoleico/análise , Animais , Manteiga/análise , Varredura Diferencial de Calorimetria , Colesterol/análise , Emulsões , Esterificação , Ácidos Graxos/análise , Óleo de Semente do Linho/análise , Óleo de Semente do Linho/química , Microscopia Confocal , Óleo de Palmeira , Tamanho da Partícula , Fitosteróis/análise , Óleos Vegetais/análise , Óleos Vegetais/química , Tocoferóis/análise , Triglicerídeos/análise
12.
J Food Sci ; 77(1): C39-45, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22122200

RESUMO

Alpha-linolenic acid (ALA) enriched structured lipid (SL) was produced by lipase-catalyzed interesterification from perilla oil (PO) and corn oil (CO). The effects of different reaction conditions (substrate molar ratio [PO/CO 1:1 to 1:3], reaction time [0 to 24 h], and reaction temperature [55 to 65 °C]) were studied. Lipozyme RM IM from Rhizomucor miehei was used as biocatalyst. We obtained 32.39% of ALA in SL obtained under the optimized conditions (molar ratio-1:1 [PO:CO], temperature-60 °C, reaction time-15 h). In SL, the major triacylglycerol (TAG) species (linolenoyl-linolenoyl-linolenoyl glycerol [LnLnLn], linolenoyl-linolenoyl-linoleoyl glycerol [LnLnL]) mainly from PO and linoleoyl-linoleoyl-oleoyl glycerol (LLO), linoleoyl-oleoyl-oleoyl glycerol (LOO), palmitoyl-linoleoyl-oleoyl glycerol (PLO) from CO decreased while linolenoyl-linolenoyl-oleoyl glycerol (LnLnO) (18.41%), trilinolein (LLL) (9.06%), LLO (16.66%), palmitoyl-linoleoyl-linoleoyl glycerol (PLL) (9.69%) were increased compared to that of physical blend. Total tocopherol content (28.01 mg/100 g), saponification value (SV) (192.2), and iodine value (IV) (161.9) were obtained. Furthermore, oxidative stability of the SL was also investigated by addition of 3 different antioxidants (each 200 ppm of rosemary extract [SL-ROS], BHT [SL-BHT], catechin [SL-CAT]) was added into SL and stored in 60 °C oven for 30 d. 2-Thiobabituric acid-reactive substances (TBARS) value was 0.16 mg/kg in SL-CAT and 0.18 mg/kg in SL-ROS as compared with 0.22 mg/kg in control (SL) after oxidation. The lowest peroxide value (POV, 200.9 meq/kg) and longest induction time (29.88 h) was also observed in SL-CAT.


Assuntos
Antioxidantes/química , Óleo de Milho/metabolismo , Proteínas Fúngicas/metabolismo , Lipase/metabolismo , Triglicerídeos/metabolismo , Ácido alfa-Linoleico/metabolismo , Catequina/química , Óleo de Milho/química , Esterificação , Conservantes de Alimentos/química , Temperatura Alta , Cinética , Concentração Osmolar , Oxirredução , Óleos Vegetais/química , Óleos Vegetais/metabolismo , Rhizomucor/enzimologia , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Tocoferóis/análise , Triglicerídeos/análise , Triglicerídeos/química , Ácido alfa-Linoleico/análise , Ácido alfa-Linoleico/química
13.
J Agric Food Chem ; 60(1): 467-75, 2012 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-22117614

RESUMO

The effects of the purple-fleshed sweet potato extract (PFSPE) on oxidation stabilities of a model oil-in-water emulsion prepared with enzymatically synthesized fish oil-soybean oil structured lipid (SL) versus physically blended lipid (PBL) without modification were evaluated. The anthocyanins in PFSPE were analyzed and identified by HPLC-MS. The fatty acid composition of SL was similar to that of PBL, except palmitic acid (1.48 in PBL and 9.61% in SL) and linoleic acid (62.47 in PBL and 49.58% in SL). Peonidin 3-caffeoylsophoroside-5-glucoside, peonidin-3-(6',6'-caffeoylferuloylsophoroside)-5-glucoside, peonidin-dicaffeoylsophoroside-5-glucoside, peonidin 3-(6',6"-caffeoyl-p-hydroxybenzoylsophoroside)-5-glucoside were identified as the major anthocyanin compounds in PFSPE. Different levels (200, 500, 1000 ppm) of PFSPE were added into both SL- and PBL-based emulsions, with 200 ppm catechin as comparison. Oxidation was monitored by measuring the peroxide value and thiobarbituric acid reactive substances. The antioxidant activity of PFSPE increased with an increased concentration, the concentration of 1000 ppm showed high antioxidant ability similar to that of catechin in both PBL- and SL-based oil-in-water emulsions. It is notable that the SL-based emulsion appeared to have better oxidative stability than the PBL-based emulsion.


Assuntos
Óleos de Peixe/química , Ipomoea batatas/química , Lipídeos/química , Extratos Vegetais/química , Emulsões/química , Oxirredução
14.
Neurosci Lett ; 498(2): 110-3, 2011 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-21420468

RESUMO

The Period1 (Per1) is a clock-oscillating gene product that plays an essential role in the generation and modulation of circadian rhythm in the suprachiasmatic nucleus (SCN) of hypothalamus. However, Per1 is also expressed in many other brain regions including cerebral cortex, hippocampus, and amygdala, suggesting that Per1 may be involved in the broader cellular functions in addition to the rhythm regulation. In this study, we found that chemical or electrical seizure-inducing stimulations regulate Per1 expression. Treatments with electric convulsive shock (ECS) or kainic acid (KA) robustly up-regulated the expressions of per1 mRNA and protein in the hippocampal formation and cerebral cortex. In consistent, we found that neuronal depolarization or KA treatment increased per1 mRNA expression in cultured primary cortical neurons. Because it has been demonstrated that Per family molecules contribute to the regulation of stress-induced cell death, we also explored the effect of Per1 overexpression on the survival of cultured neurons. However, neither basal, staurosporine- nor KA-induced neuronal death was affected by forced expression of Per1. Collectively, these results suggest that the Per1 expression is neuronal activity- and epileptogen-dependent, although its functional significance is remained to be explored.


Assuntos
Epilepsia/metabolismo , Hipocampo/metabolismo , Proteínas do Tecido Nervoso/biossíntese , Proteínas Circadianas Period/biossíntese , Animais , Células Cultivadas/efeitos dos fármacos , Córtex Cerebral/citologia , Eletrochoque , Epilepsia/induzido quimicamente , Epilepsia/etiologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Regulação da Expressão Gênica , Ácido Caínico/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/fisiologia , Neurônios/citologia , Neurônios/efeitos dos fármacos , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/fisiologia , Cloreto de Potássio/farmacologia , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Estaurosporina/farmacologia
15.
J Neurosci ; 29(44): 14039-49, 2009 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-19890013

RESUMO

Activity-dependent alterations of synaptic contacts are crucial for synaptic plasticity. The formation of new dendritic spines and synapses is known to require actin cytoskeletal reorganization specifically during neural activation phases. Yet the site-specific and time-dependent mechanisms modulating actin dynamics in mature neurons are not well understood. In this study, we show that actin dynamics in spines is regulated by a Rac anchoring and targeting function of inositol 1,4,5-trisphosphate 3-kinase A (IP(3)K-A), independent of its kinase activity. On neural activation, IP(3)K-A bound directly to activated Rac1 and recruited it to the actin cytoskeleton in the postsynaptic area. This focal targeting of activated Rac1 induced spine formation through actin dynamics downstream of Rac signaling. Consistent with the scaffolding role of IP(3)K-A, IP(3)K-A knock-out mice exhibited defects in accumulation of PAK1 by long-term potentiation-inducing stimulation. This deficiency resulted in a reduction in the reorganization of actin cytoskeletal structures in the synaptic area of dentate gyrus. Moreover, IP(3)K-A knock-out mice showed deficits of synaptic plasticity in perforant path and in hippocampal-dependent memory performances. These data support a novel model in which IP(3)K-A is critical for the spatial and temporal regulation of spine actin remodeling, synaptic plasticity, and learning and memory via an activity-dependent Rac scaffolding mechanism.


Assuntos
Regiões de Interação com a Matriz/fisiologia , Fosfotransferases (Aceptor do Grupo Álcool)/fisiologia , Transdução de Sinais/fisiologia , Sinapses/fisiologia , Proteínas rac1 de Ligação ao GTP/fisiologia , Animais , Células HeLa , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ratos , Ratos Sprague-Dawley
16.
Neurosci Lett ; 433(3): 259-64, 2008 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-18261853

RESUMO

Sox11 is a transcription factor that is proposed to be involved in the development and regeneration of the brain [M.P. Jankowski, P.K. Cornuet, S. Mcllwrath, H.R. Koerber, K.M. Albers, SRY-box containing gene 11 (Sox11) transcription factor is required for neuron survive and neurite growth, Neuroscience 143 (2006) 501-514]. In this study, we compared the expression patterns of Sox11 and its two putative binding partners, Brn1 and Brn2 during development and following transient forebrain ischemia in the rat. The spatiotemporal expression pattern of Brn1 was similar to that of Sox11 from the late embryonic to postnatal development, and they are strongly expressed in the brain regions where neuronal progenitors and immature neurons are enriched. On the other hand, Brn2 was ubiquitously expressed in most tissues including developing nervous system. Neuronal depolarization of cerebral cortex neurons in vitro enhanced both Sox11 and Brn1 expression, whereas the induction of Brn2 was only marginal, further suggesting the similar transcriptional modulation of Sox11 and Brn1. In the hippocampus, however, they showed a little different expression patterns. The expression of Brn1 was not substantial in developing dentate gyrus (DG) where Sox11 expression was strong. The transient forebrain ischemia enhanced Sox11 gene expression moderately in the CA1 and strongly in the DG, whereas Brn1 was selectively induced only in the CA1 of the hippocampal formation. Collectively, overall results suggest that the expression of Sox11 and Brn1 may be modulated by the cell-type specific machinery.


Assuntos
Envelhecimento/metabolismo , Isquemia Encefálica/metabolismo , Encéfalo/metabolismo , Proteínas de Homeodomínio/metabolismo , Ataque Isquêmico Transitório/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Fatores do Domínio POU/metabolismo , Proteína da Região Y Determinante do Sexo/metabolismo , Envelhecimento/genética , Animais , Animais Recém-Nascidos , Encéfalo/embriologia , Encéfalo/crescimento & desenvolvimento , Isquemia Encefálica/genética , Isquemia Encefálica/fisiopatologia , Células Cultivadas , Giro Denteado/embriologia , Giro Denteado/crescimento & desenvolvimento , Giro Denteado/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica no Desenvolvimento/genética , Hipocampo/embriologia , Hipocampo/crescimento & desenvolvimento , Hipocampo/metabolismo , Proteínas de Homeodomínio/genética , Ataque Isquêmico Transitório/genética , Ataque Isquêmico Transitório/fisiopatologia , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Fatores do Domínio POU/genética , Ratos , Ratos Sprague-Dawley , Proteína da Região Y Determinante do Sexo/genética , Células-Tronco/metabolismo , Ativação Transcricional/genética , Regulação para Cima/fisiologia
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