The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Masashi Mizuno - One of the best experts on this subject based on the ideXlab platform.

  • Intestinal Anti-Inflammatory Activity of Lentinan: Influence on IL-8 and TNFR1 Expression in Intestinal
    2016
    Co-Authors: Epithelial Cells, Takashi Hashimoto, Kazuki Kanazawa, Yosuke Nishitani, Ling Zhang, Masaru Yoshida, Takeshi Azuma, Masashi Mizuno
    Abstract:

    Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract. It is unknown whether b-1,3;1,6-glucan can induce immune suppressive effects. Here, we study intestinal anti-inflammatory activity of Lentinula edodes-derived b-1,3;1,6-glucan, which is known as Lentinan. Dextran sulfate sodium (DSS)-induced colitis mice were used to elucidate effects of Lentinan in vivo. In the cellular level assessment, Lentinan was added into a co-culture model consisting of intestinal epithelial Caco-2 cells and LPS-stimulated macrophage RAW264.7 cells. Ligated intestinal loop assay was performed for assessing effects of Lentinan on intestinal epithelial cells (IECs) in vivo. Oral administration of Lentinan (100 mg/mouse) significantly ameliorated DSS-induced colitis in body weight loss, shortening of colon lengths, histological score, and inflammatory cytokine mRNA expression in inflamed tissues. Lentinan reduced interleukin (IL)-8 mRNA expression and nuclear factor (NF)-kB activation in Caco-2 cells without decreasing of tumor necrosis factor (TNF)-a production from RAW264.7 cells. Flow cytometric analysis revealed that surface levels of TNF receptor (TNFR) 1 were decreased by Lentinan treatment. A clathrin-mediated endocytosis inhibitor, monodansylcadaverine, canceled Lentinan inhibition of IL-8 mRNA expression. Moreover, Lentinan inhibited TNFR1 expression in Caco-2 cells in both protein and mRNA level. Lentinan also inhibited TNFR1 mRNA expression in mouse IECs. These results suggest that Lentinan exhibits intestinal anti-inflammatory activity through inhibition of IL-8 mRNA expression associated with the inhibition of NF-k

  • Lentinan degradation in the lentinula edodes fruiting body during postharvest preservation is reduced by downregulation of the exo β 1 3 glucanase exg2
    Journal of Agricultural and Food Chemistry, 2014
    Co-Authors: Naotake Konno, Yosuke Nishitani, Keiko Nakade, Masashi Mizuno
    Abstract:

    Lentinan from Lentinula edodes fruiting bodies (shiitake mushrooms) is a valuable β-glucan for medical purposes based on its anticancer activity and immunomodulating activity. However, Lentinan content in fruiting bodies decreases after harvesting and storage due to an increase in glucanase activity. In this study, we downregulated the expression of an exo-β-1,3-glucanase, exg2, in L. edodes using RNA interference. In the wild-type strain, β-1,3-glucanase activity in fruiting bodies remarkably increased after harvesting, and 41.7% of the Lentinan content was lost after 4 days of preservation. The EXG2 downregulated strain showed significantly lower Lentinan degrading activity (60-70% of the wild-type strain) in the fruiting bodies 2-4 days after harvesting. The Lentinan content of fresh fruiting bodies was similar in the wild-type and EXG2 downregulated strains, but in the downregulated strain, only 25.4% of the Lentinan was lost after 4 days, indicating that downregulation of EXG2 enables keeping the Lentinan content high longer.

  • Lentinan Degradation in the Lentinula edodes Fruiting Body during Postharvest Preservation Is Reduced by Downregulation of the exo-β-1,3-Glucanase EXG2
    2014
    Co-Authors: Naotake Konno, Yosuke Nishitani, Keiko Nakade, Masashi Mizuno
    Abstract:

    Lentinan from Lentinula edodes fruiting bodies (shiitake mushrooms) is a valuable β-glucan for medical purposes based on its anticancer activity and immunomodulating activity. However, Lentinan content in fruiting bodies decreases after harvesting and storage due to an increase in glucanase activity. In this study, we downregulated the expression of an exo-β-1,3-glucanase, exg2, in L. edodes using RNA interference. In the wild-type strain, β-1,3-glucanase activity in fruiting bodies remarkably increased after harvesting, and 41.7% of the Lentinan content was lost after 4 days of preservation. The EXG2 downregulated strain showed significantly lower Lentinan degrading activity (60–70% of the wild-type strain) in the fruiting bodies 2–4 days after harvesting. The Lentinan content of fresh fruiting bodies was similar in the wild-type and EXG2 downregulated strains, but in the downregulated strain, only 25.4% of the Lentinan was lost after 4 days, indicating that downregulation of EXG2 enables keeping the Lentinan content high longer

  • intestinal anti inflammatory activity of Lentinan influence on il 8 and tnfr1 expression in intestinal epithelial cells
    PLOS ONE, 2013
    Co-Authors: Yosuke Nishitani, Takashi Hashimoto, Kazuki Kanazawa, Ling Zhang, Masaru Yoshida, Takeshi Azuma, Masashi Mizuno
    Abstract:

    Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract. It is unknown whether β-1,3;1,6-glucan can induce immune suppressive effects. Here, we study intestinal anti-inflammatory activity of Lentinula edodes-derived β-1,3;1,6-glucan, which is known as Lentinan. Dextran sulfate sodium (DSS)-induced colitis mice were used to elucidate effects of Lentinan in vivo. In the cellular level assessment, Lentinan was added into a co-culture model consisting of intestinal epithelial Caco-2 cells and LPS-stimulated macrophage RAW264.7 cells. Ligated intestinal loop assay was performed for assessing effects of Lentinan on intestinal epithelial cells (IECs) in vivo. Oral administration of Lentinan (100 µg/mouse) significantly ameliorated DSS-induced colitis in body weight loss, shortening of colon lengths, histological score, and inflammatory cytokine mRNA expression in inflamed tissues. Lentinan reduced interleukin (IL)-8 mRNA expression and nuclear factor (NF)-κB activation in Caco-2 cells without decreasing of tumor necrosis factor (TNF)-α production from RAW264.7 cells. Flow cytometric analysis revealed that surface levels of TNF receptor (TNFR) 1 were decreased by Lentinan treatment. A clathrin-mediated endocytosis inhibitor, monodansylcadaverine, canceled Lentinan inhibition of IL-8 mRNA expression. Moreover, Lentinan inhibited TNFR1 expression in Caco-2 cells in both protein and mRNA level. Lentinan also inhibited TNFR1 mRNA expression in mouse IECs. These results suggest that Lentinan exhibits intestinal anti-inflammatory activity through inhibition of IL-8 mRNA expression associated with the inhibition of NF-κB activation which is triggered by TNFR1 endocytosis and lowering of their expression in IECs. Lentinan may be effective for the treatment of gut inflammation including IBD.

  • Lentinan treatment ameliorates DSS-induced colitis in mice.
    2013
    Co-Authors: Yosuke Nishitani, Takashi Hashimoto, Kazuki Kanazawa, Ling Zhang, Masaru Yoshida, Takeshi Azuma, Masashi Mizuno
    Abstract:

    Oral administration of Lentinan was started 7 days prior to DSS treatment. (A) Body weight changes of DSS-induced colitis mice with or without Lentinan treatment according to the protocol described in materials and methods. Difference between 100 µg/mouse of Lentinan-treated mice and non-treated DSS colitis mice was significant at P

Lina Zhang - One of the best experts on this subject based on the ideXlab platform.

  • advances in Lentinan isolation structure chain conformation and bioactivities
    Food Hydrocolloids, 2011
    Co-Authors: Yangyang Zhang, Xiaohua Wang, Sheng Li, Lina Zhang, Peter C K Cheung
    Abstract:

    Abstract Lentinan, a β-(1 → 3)- d -glucan isolated from a common edible mushroom, Lentinus edodes, is known as a biologically active macromolecules with very strong host-mediated anti-cancer activity, via activation of the human immune system. However, its widespread medicinal application is hindered by some technical difficulties in its extraction and purification, as well as a lack of thorough understanding of the structure-and-function relationship of this polysaccharide. This review aims at highlighting the different areas of research conducted on Lentinan in the past 40 years, including its extraction and purification processes, the analysis of structure, the determination of its chain conformation and conformation transition in solution, as well as its rheological properties and bioactivities especially on anti-cancer treatment. About 156 literatures were cited to summarize the advancement of Lentinan in the review paper.

  • renaturation of triple helical polysaccharide Lentinan in water diluted dimethylsulfoxide solution
    Carbohydrate Research, 2010
    Co-Authors: Xiaohua Wang, Fu Cai, Lina Zhang
    Abstract:

    Abstract Triple helical Lentinan, a β-(1→3)- d -glucan from Lentinus edodes , was denatured in dimethylsulfoxide (DMSO) into single random coils. The randomly coiled Lentinan/DMSO solutions were diluted with pure water to w H (the weight fraction of water in the mixed solvent) of 95%, and their intrinsic viscosity [ η ], weight-average molecular weight M w , radius of gyration R g , and hydrodynamic radius R h were investigated at 25 °C after over 5-day storage. The [ η ] and M w values, especially the conformation parameter ρ (≡ R g / R h ), of the renatured Lentinan were close to those of the originally extracted one, suggesting that random Lentinan chains in DMSO were reassembled into triple helical structures. Moreover, the renatured Lentinan in 95% water/5% DMSO solution exhibited a unique behavior of triple helical glucans that shear modulus G ′ decreased sharply at temperature from 8.4 °C to 13.3 °C with increasing temperature, which was ascribed to the intramolecular conformation transition from ordered triple helical I to disordered triple helical II. The AFM images gave was suggested intuitively evidence that the renatured Lentinan mainly existed as rod-like chains, supporting that formation of triple helical structure. The optimal Lentinan concentration for triple helical configuration formation was estimated to be over 0.04%. The time dependence of R h and UV absorption of the water-diluted Lentinan/DMSO solution with an indicator of azo dye of Congo red suggested that renaturation of triple helix was a very rapid process. Moreover, the blue-shift of UV–vis absorption spectra suggested that the dye molecules of Congo red were assembled into supramolecular structure in the hydrophobic cavity of the renatured triple helical Lentinan. All the results showed that the triple helical structure formed once the randomly coiled Lentinan/DMSO was diluted to the final water content of 95%.

  • physicochemical properties and antitumor activities for sulfated derivatives of Lentinan
    Carbohydrate Research, 2009
    Co-Authors: Xiaohua Wang, Lina Zhang
    Abstract:

    Five fractions of Lentinan, a beta-(1-->3)-D-glucan bearing beta-(1-->6)-d-glucopyranosyl branches, were treated with chlorosulfonic acid for 90 min at 60 degrees C in pyridine medium to synthesize water-soluble sulfated derivatives having the substitution degree of 1.44-1.76. The (13)C NMR spectra of the sulfated beta-glucans indicated that the C-6 position was preferentially substituted by the sulfate groups. The values of the weight-average molecular weight (M(w)), radius of gyration (s(2)(z)(1/2)), and intrinsic viscosity ([eta]) of the sulfated Lentinan fractions were determined by size-exclusion chromatography with multi-angle laser light scattering (SEC-MALLS) and viscometry in 0.15 M aq NaCl at 25 degrees C, respectively. The dependence of [eta] on M(w) for the sulfated Lentinan was found to be [eta]=8.93 x 10(-3)M(w)(0.73+/-0.02) (mL/g) in 0.15 M aq NaCl (for M(w) ranging from 14.6 x 10(4) to 50.4 x 10(4)). On the basis of the Yamakawa-Fujii-Yoshizaki (YFY) theory, the conformational parameters of the sulfated Lentinan were calculated as 950 nm(-1) for the molar mass per unit contour length (M(L)), 4.8 nm for the persistence length (q), and 13.9 for the characteristic ratio (C(infinity)), indicating relatively extended single flexible chains in solution. The sulfated glucan fractions exhibited in vitro antiproliferative activities against sarcoma 180 (S-180) cells, and their inhibition ratios were lower than that of the triple-helix Lentinan, but higher than that for the one with single random-coil Lentinan chains.

  • multiple conformation transitions of triple helical Lentinan in dmso water by microcalorimetry
    Journal of Physical Chemistry B, 2009
    Co-Authors: Xiaohua Wang, Yangyang Zhang, Lina Zhang, Yanwei Ding
    Abstract:

    The hydrogen bonding interactions of the triple helical Lentinan, β-(1→3)-d-glucan from Lentinus edodes, in the mixtures of dimethyl sulfoxide (DMSO) and water were investigated by light scattering, viscometry, and ultrasensitive differential scanning calorimetry (US-DSC). The results revealed that two conformation transitions occurred in the Lentinan solution with an increase of temperature. A reversible transition from triple helix I to triple helix II, namely, from a high degree of immobilization of the backbone to a more freely rotating one, occurred in the temperature range from 8 to 45 °C. The other was an irreversible conformation transition from triple helix to single strand flexible chain at 90−140 °C, depending on the DMSO concentration. The side chain of the triple helix I Lentinan combined with water clusters through hydrogen bonds to form an associating water layer in the first region, leading to a high degree of immobilization of the backbone. However, the side chain could rotate in triple h...

  • multiple conformation transitions of triple helical Lentinan in dmso water by microcalorimetry
    Journal of Physical Chemistry B, 2009
    Co-Authors: Xiaohua Wang, Yangyang Zhang, Lina Zhang, Yanwei Ding
    Abstract:

    The hydrogen bonding interactions of the triple helical Lentinan, beta-(1-->3)-D-glucan from Lentinus edodes, in the mixtures of dimethyl sulfoxide (DMSO) and water were investigated by light scattering, viscometry, and ultrasensitive differential scanning calorimetry (US-DSC). The results revealed that two conformation transitions occurred in the Lentinan solution with an increase of temperature. A reversible transition from triple helix I to triple helix II, namely, from a high degree of immobilization of the backbone to a more freely rotating one, occurred in the temperature range from 8 to 45 degrees C. The other was an irreversible conformation transition from triple helix to single strand flexible chain at 90-140 degrees C, depending on the DMSO concentration. The side chain of the triple helix I Lentinan combined with water clusters through hydrogen bonds to form an associating water layer in the first region, leading to a high degree of immobilization of the backbone. However, the side chain could rotate in triple helix II at slightly elevated temperature, as a result of the breaking of the associating structure with relatively lower energy. The second transition resulted from the destruction of the intra- and intermolecular hydrogen bonds in Lentinan, which sustain the triple helical structure. Furthermore, the transition in the high temperature region showed high cooperation, suggesting that the intra- and intermolecular hydrogen bonds with the relatively high energy were destructed simultaneously. Therefore, the diversity of the hydrogen bonds created the multiple conformational transitions of the triple helical polysaccharide in the aqueous solution.

Xiaohua Wang - One of the best experts on this subject based on the ideXlab platform.

  • advances in Lentinan isolation structure chain conformation and bioactivities
    Food Hydrocolloids, 2011
    Co-Authors: Yangyang Zhang, Xiaohua Wang, Sheng Li, Lina Zhang, Peter C K Cheung
    Abstract:

    Abstract Lentinan, a β-(1 → 3)- d -glucan isolated from a common edible mushroom, Lentinus edodes, is known as a biologically active macromolecules with very strong host-mediated anti-cancer activity, via activation of the human immune system. However, its widespread medicinal application is hindered by some technical difficulties in its extraction and purification, as well as a lack of thorough understanding of the structure-and-function relationship of this polysaccharide. This review aims at highlighting the different areas of research conducted on Lentinan in the past 40 years, including its extraction and purification processes, the analysis of structure, the determination of its chain conformation and conformation transition in solution, as well as its rheological properties and bioactivities especially on anti-cancer treatment. About 156 literatures were cited to summarize the advancement of Lentinan in the review paper.

  • renaturation of triple helical polysaccharide Lentinan in water diluted dimethylsulfoxide solution
    Carbohydrate Research, 2010
    Co-Authors: Xiaohua Wang, Fu Cai, Lina Zhang
    Abstract:

    Abstract Triple helical Lentinan, a β-(1→3)- d -glucan from Lentinus edodes , was denatured in dimethylsulfoxide (DMSO) into single random coils. The randomly coiled Lentinan/DMSO solutions were diluted with pure water to w H (the weight fraction of water in the mixed solvent) of 95%, and their intrinsic viscosity [ η ], weight-average molecular weight M w , radius of gyration R g , and hydrodynamic radius R h were investigated at 25 °C after over 5-day storage. The [ η ] and M w values, especially the conformation parameter ρ (≡ R g / R h ), of the renatured Lentinan were close to those of the originally extracted one, suggesting that random Lentinan chains in DMSO were reassembled into triple helical structures. Moreover, the renatured Lentinan in 95% water/5% DMSO solution exhibited a unique behavior of triple helical glucans that shear modulus G ′ decreased sharply at temperature from 8.4 °C to 13.3 °C with increasing temperature, which was ascribed to the intramolecular conformation transition from ordered triple helical I to disordered triple helical II. The AFM images gave was suggested intuitively evidence that the renatured Lentinan mainly existed as rod-like chains, supporting that formation of triple helical structure. The optimal Lentinan concentration for triple helical configuration formation was estimated to be over 0.04%. The time dependence of R h and UV absorption of the water-diluted Lentinan/DMSO solution with an indicator of azo dye of Congo red suggested that renaturation of triple helix was a very rapid process. Moreover, the blue-shift of UV–vis absorption spectra suggested that the dye molecules of Congo red were assembled into supramolecular structure in the hydrophobic cavity of the renatured triple helical Lentinan. All the results showed that the triple helical structure formed once the randomly coiled Lentinan/DMSO was diluted to the final water content of 95%.

  • physicochemical properties and antitumor activities for sulfated derivatives of Lentinan
    Carbohydrate Research, 2009
    Co-Authors: Xiaohua Wang, Lina Zhang
    Abstract:

    Five fractions of Lentinan, a beta-(1-->3)-D-glucan bearing beta-(1-->6)-d-glucopyranosyl branches, were treated with chlorosulfonic acid for 90 min at 60 degrees C in pyridine medium to synthesize water-soluble sulfated derivatives having the substitution degree of 1.44-1.76. The (13)C NMR spectra of the sulfated beta-glucans indicated that the C-6 position was preferentially substituted by the sulfate groups. The values of the weight-average molecular weight (M(w)), radius of gyration (s(2)(z)(1/2)), and intrinsic viscosity ([eta]) of the sulfated Lentinan fractions were determined by size-exclusion chromatography with multi-angle laser light scattering (SEC-MALLS) and viscometry in 0.15 M aq NaCl at 25 degrees C, respectively. The dependence of [eta] on M(w) for the sulfated Lentinan was found to be [eta]=8.93 x 10(-3)M(w)(0.73+/-0.02) (mL/g) in 0.15 M aq NaCl (for M(w) ranging from 14.6 x 10(4) to 50.4 x 10(4)). On the basis of the Yamakawa-Fujii-Yoshizaki (YFY) theory, the conformational parameters of the sulfated Lentinan were calculated as 950 nm(-1) for the molar mass per unit contour length (M(L)), 4.8 nm for the persistence length (q), and 13.9 for the characteristic ratio (C(infinity)), indicating relatively extended single flexible chains in solution. The sulfated glucan fractions exhibited in vitro antiproliferative activities against sarcoma 180 (S-180) cells, and their inhibition ratios were lower than that of the triple-helix Lentinan, but higher than that for the one with single random-coil Lentinan chains.

  • multiple conformation transitions of triple helical Lentinan in dmso water by microcalorimetry
    Journal of Physical Chemistry B, 2009
    Co-Authors: Xiaohua Wang, Yangyang Zhang, Lina Zhang, Yanwei Ding
    Abstract:

    The hydrogen bonding interactions of the triple helical Lentinan, β-(1→3)-d-glucan from Lentinus edodes, in the mixtures of dimethyl sulfoxide (DMSO) and water were investigated by light scattering, viscometry, and ultrasensitive differential scanning calorimetry (US-DSC). The results revealed that two conformation transitions occurred in the Lentinan solution with an increase of temperature. A reversible transition from triple helix I to triple helix II, namely, from a high degree of immobilization of the backbone to a more freely rotating one, occurred in the temperature range from 8 to 45 °C. The other was an irreversible conformation transition from triple helix to single strand flexible chain at 90−140 °C, depending on the DMSO concentration. The side chain of the triple helix I Lentinan combined with water clusters through hydrogen bonds to form an associating water layer in the first region, leading to a high degree of immobilization of the backbone. However, the side chain could rotate in triple h...

  • multiple conformation transitions of triple helical Lentinan in dmso water by microcalorimetry
    Journal of Physical Chemistry B, 2009
    Co-Authors: Xiaohua Wang, Yangyang Zhang, Lina Zhang, Yanwei Ding
    Abstract:

    The hydrogen bonding interactions of the triple helical Lentinan, beta-(1-->3)-D-glucan from Lentinus edodes, in the mixtures of dimethyl sulfoxide (DMSO) and water were investigated by light scattering, viscometry, and ultrasensitive differential scanning calorimetry (US-DSC). The results revealed that two conformation transitions occurred in the Lentinan solution with an increase of temperature. A reversible transition from triple helix I to triple helix II, namely, from a high degree of immobilization of the backbone to a more freely rotating one, occurred in the temperature range from 8 to 45 degrees C. The other was an irreversible conformation transition from triple helix to single strand flexible chain at 90-140 degrees C, depending on the DMSO concentration. The side chain of the triple helix I Lentinan combined with water clusters through hydrogen bonds to form an associating water layer in the first region, leading to a high degree of immobilization of the backbone. However, the side chain could rotate in triple helix II at slightly elevated temperature, as a result of the breaking of the associating structure with relatively lower energy. The second transition resulted from the destruction of the intra- and intermolecular hydrogen bonds in Lentinan, which sustain the triple helical structure. Furthermore, the transition in the high temperature region showed high cooperation, suggesting that the intra- and intermolecular hydrogen bonds with the relatively high energy were destructed simultaneously. Therefore, the diversity of the hydrogen bonds created the multiple conformational transitions of the triple helical polysaccharide in the aqueous solution.

Yangyang Zhang - One of the best experts on this subject based on the ideXlab platform.

  • advances in Lentinan isolation structure chain conformation and bioactivities
    Food Hydrocolloids, 2011
    Co-Authors: Yangyang Zhang, Xiaohua Wang, Sheng Li, Lina Zhang, Peter C K Cheung
    Abstract:

    Abstract Lentinan, a β-(1 → 3)- d -glucan isolated from a common edible mushroom, Lentinus edodes, is known as a biologically active macromolecules with very strong host-mediated anti-cancer activity, via activation of the human immune system. However, its widespread medicinal application is hindered by some technical difficulties in its extraction and purification, as well as a lack of thorough understanding of the structure-and-function relationship of this polysaccharide. This review aims at highlighting the different areas of research conducted on Lentinan in the past 40 years, including its extraction and purification processes, the analysis of structure, the determination of its chain conformation and conformation transition in solution, as well as its rheological properties and bioactivities especially on anti-cancer treatment. About 156 literatures were cited to summarize the advancement of Lentinan in the review paper.

  • multiple conformation transitions of triple helical Lentinan in dmso water by microcalorimetry
    Journal of Physical Chemistry B, 2009
    Co-Authors: Xiaohua Wang, Yangyang Zhang, Lina Zhang, Yanwei Ding
    Abstract:

    The hydrogen bonding interactions of the triple helical Lentinan, β-(1→3)-d-glucan from Lentinus edodes, in the mixtures of dimethyl sulfoxide (DMSO) and water were investigated by light scattering, viscometry, and ultrasensitive differential scanning calorimetry (US-DSC). The results revealed that two conformation transitions occurred in the Lentinan solution with an increase of temperature. A reversible transition from triple helix I to triple helix II, namely, from a high degree of immobilization of the backbone to a more freely rotating one, occurred in the temperature range from 8 to 45 °C. The other was an irreversible conformation transition from triple helix to single strand flexible chain at 90−140 °C, depending on the DMSO concentration. The side chain of the triple helix I Lentinan combined with water clusters through hydrogen bonds to form an associating water layer in the first region, leading to a high degree of immobilization of the backbone. However, the side chain could rotate in triple h...

  • multiple conformation transitions of triple helical Lentinan in dmso water by microcalorimetry
    Journal of Physical Chemistry B, 2009
    Co-Authors: Xiaohua Wang, Yangyang Zhang, Lina Zhang, Yanwei Ding
    Abstract:

    The hydrogen bonding interactions of the triple helical Lentinan, beta-(1-->3)-D-glucan from Lentinus edodes, in the mixtures of dimethyl sulfoxide (DMSO) and water were investigated by light scattering, viscometry, and ultrasensitive differential scanning calorimetry (US-DSC). The results revealed that two conformation transitions occurred in the Lentinan solution with an increase of temperature. A reversible transition from triple helix I to triple helix II, namely, from a high degree of immobilization of the backbone to a more freely rotating one, occurred in the temperature range from 8 to 45 degrees C. The other was an irreversible conformation transition from triple helix to single strand flexible chain at 90-140 degrees C, depending on the DMSO concentration. The side chain of the triple helix I Lentinan combined with water clusters through hydrogen bonds to form an associating water layer in the first region, leading to a high degree of immobilization of the backbone. However, the side chain could rotate in triple helix II at slightly elevated temperature, as a result of the breaking of the associating structure with relatively lower energy. The second transition resulted from the destruction of the intra- and intermolecular hydrogen bonds in Lentinan, which sustain the triple helical structure. Furthermore, the transition in the high temperature region showed high cooperation, suggesting that the intra- and intermolecular hydrogen bonds with the relatively high energy were destructed simultaneously. Therefore, the diversity of the hydrogen bonds created the multiple conformational transitions of the triple helical polysaccharide in the aqueous solution.

  • rheology of triple helical Lentinan in solution steady shear viscosity and dynamic oscillatory behavior
    Food Hydrocolloids, 2008
    Co-Authors: Yangyang Zhang, Lina Zhang
    Abstract:

    Abstract The steady shear viscosity and dynamic oscillatory behaviors of triple helical Lentinan, a β-(1→3)- d -glucan from Lentinus edodes, in water at 25 °C were studied by Rheometric Scientific ARES-controlled strain rheometer. The intrinsic viscosity was measured by Ubbelohde viscometer and estimated to be 903.3 mL/g from the intercept of the linear plot of ηsp/c vs. ηsp. As found for normal disordered polysaccharides, shear-thinning behavior was observed. But a peculiarity is that the shear-thinning behavior occurred at lower concentration and very low critical shear rate. The zero shear viscosity (η0) and specific viscosity (ηsp) increased with an increase of polymer concentration and degree of space occupancy (c[η]), respectively, similar to the general trend of most disordered polysaccharides. The critical concentration c*, at which the transition from a dilute solution of independently moving chains to a network occurred, was determined to be about 3.8×10−4 g/mL, which was much lower than that of general disordered polymers. This may be attributable to the nature of stiffness of triple helical Lentinan. The results from dynamic experiments revealed that Lentinan in pure water could form cross-linked network structure and weak gels with increasing polysaccharide concentration.

  • dynamic viscoelastic behavior of triple helical Lentinan in water effects of concentration and molecular weight
    Polymer, 2007
    Co-Authors: Yangyang Zhang, Lina Zhang
    Abstract:

    Abstract The dynamic viscoelasitc behavior of Lentinan, one triple helical β-(1 → 3)- d -glucan from the fruiting body of Lentinus edodes , in water was investigated as a function of concentration and molecular weight at 25 °C by using dynamic rheology. It was revealed that the shear storage moduli ( G ′), viscous loss moduli ( G ″), and the dynamic complex viscosity ( η ∗ ) exhibited strong dependence on concentration and molecular weight. At low concentrations, the Lentinan/water systems displayed liquid-like behavior with G ′ lower than G ″ at low frequencies and crossing-over at high frequencies. With increasing concentration, the elastic response of the Lentinan/water system was stronger than the viscous response, leading to the conclusion that the Lentinan/water systems displayed a predominantly solid-like behavior. The gel point ( c gel ) was determined from Winter–Chambon method (frequency-independence of tan  δ ). The most important point is that the c gel was much lower than some synthesized polymers and other flexible polysaccharides, which may be attributable to the high stiffness of triple helical Lentinan and strong intra- and intermolecular interactions among polysaccharide chains. Furthermore, a decrease in molecular weight leads to a sharp increase of c gel . The dynamic strain sweep measurements proved that the gelation of Lentinan in water is induced by the extremely entangled and stiff triple helices forming continuous network, and the Lentinan gel is structurally more like a solution that is unable to flow within a timescale of usual observation.

Kenichiro Minato - One of the best experts on this subject based on the ideXlab platform.

  • Characterization of the Lentinula edodes exg2 gene encoding a Lentinan-degrading exo-β-1,3-glucanase
    Current Genetics, 2005
    Co-Authors: Yuichi Sakamoto, Masashi Mizuno, Kenichiro Minato, Masaru Nagai, Toshitsugu Sato
    Abstract:

    Lentinan, an antitumor substance purified from Lentinula edodes , is degraded during post-harvest preservation as a result of increased glucanase activity. We isolated an exo-β-1,3-glucanase encoding gene, exg2 , from L. edodes which is a homologue of an exo-glucanase-encoding gene conserved in ascomycetous fungi. The exg2 gene was cloned as an approximately 2.4-kbp cDNA, and as a genomic sequence of 3.9-kbp. The product of the exg2 gene is predicted to contain 759 amino acids with a molecular weight of 79 kDa and a pI value of 4.6. The putative N-terminus of EXG2 is identical to the N-terminal sequences of Lentinan-degrading enzymes, GNase I and II, and a custom-made anti-EXG2 peptide anti-serum cross-reacted with purified GNase I and II. Transcription and translation of exg2 was low in the gills of mature fruiting bodies, but increased after harvesting. We conclude that the exg2 gene is a Lentinan-degrading enzyme-encoding-gene in L. edodes .

  • an exo β 1 3 glucanase synthesized de novo degrades Lentinan during storage of lentinule edodes and diminishes immunomodulating activity of the mushroom
    Carbohydrate Polymers, 2004
    Co-Authors: Kenichiro Minato, Hironobu Tsuchida, Sachiko Kawakami, Keiichi Nomura, Masashi Mizuno
    Abstract:

    Abstract Two β-1,3-glucanase isoenzymes, GNase I and II, were isolated from Lentinule edodes fruiting body. They degraded Lentinan in an exo manner during storage of the mushroom. GNase I and II were monomeric proteins with apparent molecular masses of 72.9 and 74.7 kDa, respectively. It was shown that K m values for GNase I and GNase II against Lentinan were 1.02 and 2.41 μM, respectively. Moreover, it was demonstrated by western blotting analysis that this enzyme was synthesized de novo in L. edodes during storage at 20 °C, but not at 1 or 5 °C. And this pattern of western blot was consistent with that of glucanase activity during storage of L. edodes . In addition, the immunomodulating effects of Lentinan on TNF-α and NO production were diminished with its degradation by this enzyme. These results suggested that synthesis of exo β-1,3-glucanases were induced under storage conditions at 20 °C, and Lentinan degradation by their attack might result in the depletion of immunomodulating activity of L. edodes .

  • autolysis of Lentinan an antitumor polysaccharide during storage of lentinus edodes shiitake mushroom
    Journal of Agricultural and Food Chemistry, 1999
    Co-Authors: Kenichiro Minato, Masashi Mizuno, Hirofumi Terai, Hironobu Tsuchida
    Abstract:

    The Lentinan contents in the Lentinus edodes fruit body during storage were examined by ELISA method using anti-Lentinan antibodies. The Lentinan content (12.8 mg.g(-)(1) dw) before storage decreased to 3.7 mg.g(-)(1) dw over 7 days at 20 degrees C. However, it only slightly decreased at 1 degrees C and only decreased to 9.3 mg. g(-)(1) dw at 5 degrees C. Glucanase activity, which seems to be associated with Lentinan degradation, increased more during storage of L. edodes at 20 degrees C than it did at lower temperatures. In addition, only glucose was detected as a degraded product from Lentinan by the glucanase. This suggested that this enzyme would fit the profile of an exo-type glucanase. Also, polyphenol oxidase activity, known as an index of freshness reduction in the mushroom, increased approximately 2.7-fold (to 61.5 units.mg(-)(1)) over 7 days during storage at 20 degrees C. However, its activity changed little during storage at lower temperatures. These results indicate that the reduction during storage of the quality of L. edodes as a functional food is accompanied by the decrease of Lentinan, and by browning, and that exo-glucanase plays an important role in the decrease of Lentinan content.