First isolation and structural determination of cyclic β-(1→2)-glucans from an alga, Chlorella pyrenoidosa

Suárez, Erick Reyes; Bugden, Sarah M.; Kai, Fui Boon; Kralovec, Jaroslav A.; Noseda, Miguel D.; Barrow, Colin J.; Grindley, T. Bruce

doi:10.1016/j.carres.2008.07.009

Cited by 49 publications

(6 citation statements)

References 62 publications

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“…A. platensis has been widely consumed as nutritional supplement due to its associated health benefits, such as high protein (up to 60%), vitamin B12, γlinolenic acid (GLA) and phycocyanin content [20]. Chlorella is also rich in protein, as well as pigments and glucans which can act as immunostimulants [21][22].…”

Section: Introductionmentioning

confidence: 99%

Microalgae biomass as an alternative ingredient in cookies: Sensory, physical and chemical properties, antioxidant activity and in vitro digestibility

et al. 2017

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Microalgae can be regarded as an alternative and promising food ingredient due to their nutritional composition, richness in bioactive compounds, and because they are considered a sustainable protein source for the future. The aim of this work was to evaluate microalgae (Arthrospira platensis F & M-C256, Chlorella vulgaris Allma, Tetraselmis suecica F & M-M33 and Phaeodactylum tricornutum F & M-M40) as innovative ingredients to enhance functional properties of cookies. Two biomass levels were tested and compared to control: 2% (w/w) and 6% (w/ w), to provide high levels of algae-bioactives. The cookies sensory and physical properties were evaluated during eight weeks showing high color and texture stability. Cookies prepared with A. platensis and C. vulgaris presented significantly (p < 0.05) higher protein content compared to the control, and by sensory analysis A. platensis cookies were preferred. Besides, A. platensis also provided a structuring effect in terms of cookies texture. All microalgae-based cookies showed significantly higher (p < 0.05) total phenolic content and in vitro antioxidant capacity compared to the control. No significant difference (p < 0.05) in in vitro digestibility between microalgae cookies and the control was found.

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Section: Introductionmentioning

confidence: 99%

Microalgae biomass as an alternative ingredient in cookies: Sensory, physical and chemical properties, antioxidant activity and in vitro digestibility

et al. 2017

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“…Roles of modulation of intracellular osmotic pressure and intracellular iron homeostasis have also been reported (13)(14)(15). Recently, cyclic ␤-1,2-glucan was also found in Eukaryotes such as Chlorella pyrenoidosa, an edible green microalga beneficial for immunostimulatory activity (16). There is some variety in the degree of polymerization (DP) of cyclic ␤-1,2-glucans.…”

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confidence: 96%

“…There is some variety in the degree of polymerization (DP) of cyclic ␤-1,2-glucans. C. pyrenoidosa, Brucella abortus, and Agrobacterium tumefaciens (classified into Rhizobium radiobacter to date) produce cyclic ␤-1,2-glucans with DP of ϳ20, whereas Rhizobium meliloti produces cyclic ␤-1,2-glucan with DP of around 40 (3)(4)(5)16). In B. abortus, the DP of cyclic ␤-1,2-glucans is controlled by the C-terminal domain acting on ␤-1,2-gluco-oligosaccharides (sophorooligosaccharides, Sop n s, where n denotes DP) in cyclic ␤-1,2-glucan synthase (17,18).…”

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confidence: 99%

Identification, characterization, and structural analyses of a fungal endo-β-1,2-glucanase reveal a new glycoside hydrolase family

Tanaka

Nakajima

Narukawa-Nara

et al. 2019

Journal of Biological Chemistry

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Edited by Joseph M. Jez endo-␤-1,2-Glucanase (SGL) is an enzyme that hydrolyzes ␤-1,2-glucans, which play important physiological roles in some bacteria as a cyclic form. To date, no eukaryotic SGL has been identified. We purified an SGL from Talaromyces funiculosus (TfSGL), a soil fungus, to homogeneity and then cloned the complementary DNA encoding the enzyme. TfSGL shows no significant sequence similarity to any known glycoside hydrolase (GH) families, but shows significant similarity to certain eukaryotic proteins with unknown functions. The recombinant TfSGL (TfSGLr) specifically hydrolyzed linear and cyclic ␤-1,2-glucans to sophorose (Glc-␤-1,2-Glc) as a main product. TfSGLr hydrolyzed reducing-end-modified ␤-1,2-gluco-oligosaccharides to release a sophoroside with the modified moiety. These results indicate that TfSGL is an endo-type enzyme that preferably releases sophorose from the reducing end of substrates. Stereochemical analysis demonstrated that TfSGL is an inverting enzyme. The overall structure of TfSGLr includes an (␣/␣) 6 toroid fold. The substrate-binding mode was revealed by the structure of a Michaelis complex of an inactive TfSGLr mutant with a ␤-1,2-glucoheptasaccharide. Mutational analysis and action pattern analysis of ␤-1,2-gluco-oligosaccharide derivatives revealed an unprecedented catalytic mechanism for substrate hydrolysis. Glu-262 (general acid) indirectly protonates the anomeric oxygen at subsite ؊1 via the 3-hydroxy group of the Glc moiety at subsite ؉2, and Asp-446 (general base) activates the nucleophilic water via another water. TfSGLr is apparently different from a GH144 SGL in the reaction and substrate recognition mechanism based on structural comparison. Overall, we propose that TfSGL and closely-related enzymes can be classified into a new family, GH162.

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“…Soluble polysaccharides are the main components among different constituents of aqueous extracts from plants and algal species that are responsible for immunomodulatory activities (3,4). Differ-ent polysaccharides show different biological effects that are related to their structural features including molecular weight and chemical compositions (5)(6)(7).…”

Section: Introductionmentioning

confidence: 99%

“…Such isolated polysaccharide fractions may show higher immunomodulatory behavior than CP, which makes them worthy to be assessed in immune cell systems (7).…”

Section: Introductionmentioning

confidence: 99%

Optimization of Enhanced Expression of Interferon-γ and Interleukin-2 in Chicken Peripheral Blood Mononuclear Cells by Polysaccharide Immunomodulators Using Historical-Data Response Surface Methodology

Mirzaie

2019

Gene Cell Tissue

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Background: Natural polysaccharides have been found to act as potent immunomodulatory agents. Objectives: The present study aimed to assess and optimize the concentration of polysaccharides driven from Chlorella by-product (CBP) for interferon-γ (IFN-γ) and interleukin-2 (IL-2) gene expression by chicken peripheral blood mononuclear cells (PBMCs). Methods: In this study, a crude polysaccharide (CP) was extracted from CBP and fractionated to F1 and F2 using anion-exchange chromatography. Extracted polysaccharides were used at the concentrations of 200 to 1000 µg/mL in the culture medium for PBMCs.The data were analyzed by historical-data response surface methodology (RSM) approach. The analysis of variance test was applied to check the significance of RSM results. Results: The effects of immunomodulator type and concentration were statistically significant (P < 0.0001) on both cytokines. In addition, the interaction effect was also significant for IFN-γ expression (P = 0.03). The regression models of IFN-γ and IL-2 expression were confirmed by the non-significant lack of fit (P = 0.056 and P = 0.066, respectively), the determination coefficient (R 2 = 0.98 and R 2 = 0.96, respectively), and adjusted determination coefficient (Adj. R 2 = 0.97 and Adj. R 2 = 0.94, respectively). The predicted determination coefficients (Pred. R 2 = 0.96 and Pred. R 2 = 0.92 for IFN-γ and IL-2 expression, respectively) were in reasonable agreement with the adjusted R 2 values and confirmed that the models had a good predictive ability. The adequate precision values of above 4 (37.51 and 24.45 for IFN-γ and IL-2, respectively) also proved the established models could navigate the design space. Furthermore, the optimization results by the historical-data design of RSM revealed that F1 at 786.68 µg/mL with the desirability of 0.87 could be selected to maximize the gene expression of IFN-γ and IL-2 by chicken PBMCs. Conclusions: It is concluded that the immunostimulatory effect was more prominent for F1 than for CP or F2 polysaccharides. In addition, historical-data RSM showed to be a valuable technique to optimize the factors and reach maximum gene expression in chicken PBMCs. Further investigations are now in progress to determine the interrelationship between the molecular structure and bioactivities of CP and fractionated polysaccharides.

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First isolation and structural determination of cyclic β-(1→2)-glucans from an alga, Chlorella pyrenoidosa

Cited by 49 publications

References 62 publications

Microalgae biomass as an alternative ingredient in cookies: Sensory, physical and chemical properties, antioxidant activity and in vitro digestibility

Microalgae biomass as an alternative ingredient in cookies: Sensory, physical and chemical properties, antioxidant activity and in vitro digestibility

Identification, characterization, and structural analyses of a fungal endo-β-1,2-glucanase reveal a new glycoside hydrolase family

Optimization of Enhanced Expression of Interferon-γ and Interleukin-2 in Chicken Peripheral Blood Mononuclear Cells by Polysaccharide Immunomodulators Using Historical-Data Response Surface Methodology

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