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Gabriella Gazzani - One of the best experts on this subject based on the ideXlab platform.

  • Anti- and pro-oxidant activity of Cichorium genus vegetables and effect of thermal treatment in biological systems
    Food Chemistry, 2006
    Co-Authors: Adele Papetti, Maria Daglia, Pietro Grisoli, Cesare Dacarro, C. Gregotti, Gabriella Gazzani
    Abstract:

    Abstract The antiradical activity of water soluble components in six vegetables belonging to the Cichorium genus, i.e., three cultivars of red intybus species var. silvestre (Treviso, Chioggia, Verona red chicories), a white intybus species var. foliosum (Belgian chicory), and two vegetables of the endivia species var. latifolium (escarole chicory) and var. crispum (“crispa” chicory), were studied using two biological systems consisting of: (1) Microsome Membrane rat hepatocyties in which oxidative damage was induced by CCl4; (2) gram-positive bacterium, Staphylococcus aureus cultures, subjected to damage with cumene hydroperoxyde. The obtained results show that in both systems the red vegetables possess the strongest antioxidant properties and contain different antioxidant compounds whether at a low or high molecular weight, but only those of high molecular-weight (MW > 3500 Da) are able to act as antioxidants in all the used systems. The lower MW fraction (MW

Saburo Matsuo - One of the best experts on this subject based on the ideXlab platform.

  • ER-resident Gi2 protein controls sar1 translocation onto the ER during budding of transport vesicles.
    Journal of cellular biochemistry, 2011
    Co-Authors: Hiroshi Nakagawa, Haruka Umadome, Shuichi Miyazaki, Katsuhiro Tanaka, Kazuhiko Nishimura, Masayuki Komori, Saburo Matsuo
    Abstract:

    In our previous study, fluoride ([AlF(4) ](-) ) disturbed ER-to-Golgi transport through the activation of ER-resident heterotrimeric G protein (ER-G protein). Therefore, ER-G protein may be implicated in ER-to-Golgi transport at the early stage prior to coat protein assembly. Sar1 translocation onto the endoplasmic reticulum (ER) Membrane is suppressed by non-selective protein kinase inhibitor H89, suggesting the participation of H89-sensitive kinase in this process. To investigate the involvement of ER-G protein in ER-to-Golgi transport, the effect of G(i) protein activator (mastoparan 7) was examined on Sar1 translocation onto the ER in a cell-free system consisting of Microsome Membrane and cytosol. Sar1 translocation onto the Microsome Membrane was induced by addition of GTPγS in the cell-free system. Translocation of Sar1 by GTPγS was suppressed significantly by both H89 and mastoparan 7. Mastoparan 7 suppressed the translocation of Sar1 onto the Microsome Membrane with dosage dependency, but mastoparan 17, the inactive analog of mastoparan 7, had no effect on Sar1 translocation. The suppressive effect of mastoparan 7 was recovered by treatment with pertussis toxin (IAP). Moreover, G(i2) protein was detected on the Microsome Membrane by western blotting for heterotrimeric G(i) proteins. These results indicate that ER-G(i2) protein modulated Sar1 translocation onto the ER, suggesting that ER-resident G(i2) protein is an important negative regulator of vesicular transport at the early stage of vesicle formation before coat protein assembly on the ER.

Adele Papetti - One of the best experts on this subject based on the ideXlab platform.

  • Anti- and pro-oxidant activity of Cichorium genus vegetables and effect of thermal treatment in biological systems
    Food Chemistry, 2006
    Co-Authors: Adele Papetti, Maria Daglia, Pietro Grisoli, Cesare Dacarro, C. Gregotti, Gabriella Gazzani
    Abstract:

    Abstract The antiradical activity of water soluble components in six vegetables belonging to the Cichorium genus, i.e., three cultivars of red intybus species var. silvestre (Treviso, Chioggia, Verona red chicories), a white intybus species var. foliosum (Belgian chicory), and two vegetables of the endivia species var. latifolium (escarole chicory) and var. crispum (“crispa” chicory), were studied using two biological systems consisting of: (1) Microsome Membrane rat hepatocyties in which oxidative damage was induced by CCl4; (2) gram-positive bacterium, Staphylococcus aureus cultures, subjected to damage with cumene hydroperoxyde. The obtained results show that in both systems the red vegetables possess the strongest antioxidant properties and contain different antioxidant compounds whether at a low or high molecular weight, but only those of high molecular-weight (MW > 3500 Da) are able to act as antioxidants in all the used systems. The lower MW fraction (MW

Geoffrey D. Holman - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of GLUT4 and GLUT1 subcellular trafficking in basal and insulin-stimulated 3T3-L1 cells.
    The Journal of biological chemistry, 1993
    Co-Authors: Jing Yang, Geoffrey D. Holman
    Abstract:

    The two glucose transporter isoforms GLUT4 and GLUT1 present in 3T3-L1 cells were labeled in the insulin-stimulated and basal states with the impermeant bis-mannose photolabel, 2-N-4-(1-azi-2,2,2-trifluoroethyl)benzoyl-1,3-bis-(D-mannos- 4-yloxy)-2-propylamine. The redistributions of these labeled transporters from the plasma Membrane to the low density Microsome Membrane fraction were followed while cells were maintained at either insulin-stimulated or basal steady states. In both these steady states GLUT4 and GLUT1 were continuously recycled. Analysis of the time courses for tracer-tagged GLUT4 and GLUT1 redistribution showed that the endocytosis rate constants were only approximately 30% slower in the insulin-stimulated (0.08 and 0.093 min-1) compared with the basal (0.116 and 0.121 min-1) state. In the insulin-stimulated state, the rate constants for GLUT4 and GLUT1 exocytosis (0.086 and 0.096 min-1) were similar to those of endocytosis. In contrast, the exocytosis rate constants of GLUT4 and GLUT1 in the basal state were 0.01 and 0.035 min-1. We therefore conclude that the main effect of insulin is to increase GLUT4 and GLUT1 exocytosis rate constants by approximately 9- and 3-fold, respectively, and that the unique feature of the GLUT4 isoform is the very slow rate of exocytosis in the basal state.

  • Determination of the rates of appearance and loss of glucose transporters at the cell surface of rat adipose cells.
    Biochemical Journal, 1991
    Co-Authors: A E Clark, Geoffrey D. Holman, I J Kozka
    Abstract:

    We have used an impermeant bis-mannose compound (2-N-[4-(1-azi-2,2,2-trifluoroethyl)benzoyl]-1,3-bis-(D-mannos+ ++- 4-yloxy)-2- propylamine; ATB-BMPA) to photolabel the glucose transporter isoforms GLUT4 and GLUT1 that are present in rat adipose cells. Plasma-Membrane fractions and light-Microsome Membrane fractions were both labelled by ATB-BMPA. The labelling of GLUT4 in the plasma Membrane fraction from insulin-treated cells was approximately 3-fold higher than that of basal cells and corresponded with a decrease in the labelling of the light-Microsome fraction. In contrast with this, the cell-surface labelling of GLUT4 from insulin-treated intact adipose cells was increased approximately 15-fold above basal levels. In these adipose cell preparations, insulin stimulated glucose transport activity approximately 30-fold. Thus the cell-surface labelling, but not the labelling of Membrane fractions, closely corresponded with the stimulation of transport. The remaining discrepancy may be due to an approx. 2-fold activation of GLUT4 intrinsic transport activity. We have studied the kinetics of trafficking of transporters and found the following. (1) Lowering the temperature to 18 degrees C increased basal glucose transport and levels of cell-surface glucose transporters by approximately 3-fold. This net increase in transporters probably occurs because the process of recruitment of transporters is less temperature-sensitive than the process involved in internalization of cell-surface transporters. (2) The time course for insulin stimulation of glucose transport activity occurred with a slight lag period of 47 s and a t 1/2 3.2 min. The time course of GLUT4 and GLUT1 appearance at the cell surface showed no lag and a t 1/2 of approximately 2.3 min for both isoforms. Thus at early times after insulin stimulation there was a discrepancy between transporter abundance and transport activity. The lag period in the stimulation of transport activity may represent the time required for the approximately 2-fold stimulation of transporter intrinsic activity. (3) The decrease in transport activity after insulin removal occurred with a very high activation energy of 159 kJ.mol-1. There was thus no significant decrease in transport or less of cell-surface transporters over 60 min at 18 degrees C. The decrease in transport activity occurred with a t1/2 of 9-11 min at 37 degrees C.(ABSTRACT TRUNCATED AT 400 WORDS)

Liang Y - One of the best experts on this subject based on the ideXlab platform.

  • Hypoglycemic effects of peroxovanadate complexes on glucose transportor of diabetic rats
    Zhonghua yi xue za zhi, 1997
    Co-Authors: Yuan M, Yu B, Liang Y
    Abstract:

    OBJECTIVE To demonstrate the hypoglycemic effects and translocation of glucose transport (Glut 1 and Glut 4) promoted by peroxovanadate and nicotinic acid complexes (POR) in streptozotozin-induced diabetic rats. METHODS Peroxovanadate complexes nicotinic acid (POR) was prepared in laboratory. POR and vanadate were administered in drink water. The muscles from diabetic rats were subjected to sucrose density gradient centrifugation to prepare plasma Membrane and Microsome Membrane. Antibodies to COOH-terminal of glucose transportor were used in Western Blot to evaluate the translocation. RESULTS Peroxovanadate complexes of nicotinic acid (POR) showed marked hypoglycemic effects on STZ-induced diabetic rats. 1mg/kg oral pathway POR could significantly reduce the plasma glucose levels (from 18.95 +/- 2.61mmol/L to 6.36 +/- 2.23mmol/L, t = 12.233, P < 0.01) over four week's treatment, whereas, same dose of single sodium vanadate or nicotinic acid did not have hypoglycemic effects. The net vanadium intake was about 1/90 of single effectively vanadate treatment. When Western blot was used POR increased the translocation of Glut 4 and Glut 1 from intracellular site of plasma Membrane. CONCLUSION Peroxovanadate-nicotinic acid complexes (POR) are the novel vanadyl that markedly reduce plasma glucose in a lower dose comparing to vanadate in STZ-DM rats by oral administration. Translocation of glucose transportor may play a part in hypoglycemic mechanism.

  • Effects of peroxovanadate complexes on reducing glycemia in diabetic rats and translocation of glucose transporter.
    Chinese medical journal, 1997
    Co-Authors: Yuan M, Yu B, Liang Y
    Abstract:

    OBJECTIVE To demonstrate the hypoglycemic effects and translocation of glucose transporter (Glut 1 and Glut 4) promoted by peroxovanadate and nicotinic acid complexes (nicotinic chelated bitriperoxovanadate, POR; N-O nicotinic chelated peroxovanadate, POV) in streptozotozin-induced diabetic rats. METHODS Peroxovanadate complexes of nicotinic acid (POR and POV) were prepared and characterized in laboratory. POR, POV and vanadate were administrated in drink water. The muscles from diabetic rats were subjected to prepare plasma Membrane and Microsome Membrane. Antibodies to COOH-terminal of glucose transporter were used in Western Blot to evaluate the translocation. RESULTS POR and POV showed markedly hypoglycemic effects in streptozotocin (STZ)-induced diabetic rats. POV, which may be a N-oxide compound of peroxovanadate, have high potency of acute effects comparing to carboxylate-complexes of peroxovanadate (POR). In chronic tests, 1 mg/kg oral pathway POR could significantly reduce the plasma glucose levels over four week's treatment, whereas the same dose of single sodium vanadate or nicotinic acid did not have hypoglycemic effects. The net vanadium intake is about 1/90 of single effectively vanadate treatment. The Western Blot showed that POR increased the translocation of Glut 4 and Glut 1 from intracellular site of Membrane. CONCLUSIONS Peroxovanadate-nicotinic acid complexes (POR and POV) are the novel vanadyl that acutely and markedly reduce plasma glucose in a lower dose comparing to vanadate in STZ-DM rats by oral administration. Translocation of glucose transportor may take a part in their hypoglycemic effects.