Relationship between conformation and biological response for (1→3)-β-d-glucans in the activation of coagulation Factor G from limulus amebocyte lysate and host-mediated antitumor activity. Demonstration of single-helix conformation as a stimulant.

Saitô, Hazime; Yoshioka, Yoshiaki; Uehara, Nobuaki; Aketagawa, Jun; Tanaka, Shigenori; Shibata, Yûkô

doi:10.1016/0008-6215(91)84128-2

Cited by 153 publications

(57 citation statements)

References 26 publications

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“…We have previously reported that reactivity is significantly affected by the degree of branching, and that reactivity decreases with increasing degree of substitution (55). Moreover, high-molecular-weight β-1,3-D-glucans have been clearly shown to assume specific higher order structures in the form of triple helix and single helix structures in dilute alkaline aqueous solutions and suspensions (33,39,40). On the other hand, low-molecularweight β-1,3-D-glucans exist in the form of random coils (1).…”

Section: Chemistry and Biology Of Angiitis Inducer Candida Albicans mentioning

confidence: 99%

Chemistry and Biology of Angiitis Inducer, Candida albicans Water‐Soluble Mannoprotein‐β‐Glucan Complex (CAWS)

Ohno

2003

Microbiology and Immunology

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Section: Chemistry and Biology Of Angiitis Inducer Candida Albicans mentioning

confidence: 99%

Chemistry and Biology of Angiitis Inducer, Candida albicans Water‐Soluble Mannoprotein‐β‐Glucan Complex (CAWS)

Ohno

2003

Microbiology and Immunology

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“…Studies evaluating the molecular weight dependence of antitumor activity have suggested that the triple-helix form is the most potent conformer of schizophyllan (SPG) (10,11). However, other studies, using solid state 13 C NMR spectroscopy, have suggested that for antitumor activity (3,12,13) and the production of tumor necrosis factor, nitric oxide, and hydrogen peroxide by macrophage (14,15), the single-helix is the potent conformer (15).…”

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confidence: 96%

Observation of a Partially Opened Triple-helix Conformation in 1→3-β-Glucan by Fluorescence Resonance Energy Transfer Spectroscopy

Young¹,

Dong²,

Jacobs³

2000

Journal of Biological Chemistry

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This study used fluorescence resonance energy transfer (FRET) spectroscopy as an indirect method to investigate the effect of NaOH treatment on the conformation of a triple-helix (133)-␤-D-glucan and then evaluated the effect of conformation on biological activity. Previous studies have suggested that treatment of the triple-helix glucans with NaOH produces single-helix conformers. FRET spectra of the triple-helix glucan, laminarin, doubly labeled with 1-aminopyrene as donor probe and fluorescein-5-isothiocyanate as acceptor probe attached at the reducing end, showed that a partially opened triplehelix conformer was formed on treatment with NaOH. Increasing degrees of strand opening was associated with increasing concentrations of NaOH. Based on these observations we propose that a partially opened triplehelix rather than a single helix, is formed by treating the triple-helix glucans with NaOH. After neutralizing the NaOH, changes in FRET indicated that the partially opened conformer gradually reverts to the triple-helix over 8 days. Laminarian was stabilized at different degrees of partial opening and its biological activity examined using the Limulus amebocyte lysate assay and nitric oxide production by alveolar macrophage. Both Limulus amebocyte lysate activity and nitric oxide production were related to the degree of opening of the triple-helix. Partially open conformers were more biologically active than the intact triple-helix.(133)-␤-D-Glucans have been shown to systemically enhance the immune system, resulting in antitumor, antibacterial, and wound healing activities (1). Differences in these activities are thought to be related to three factors: molecular conformation, the degree of branching, and the molecular weight (M r ) (2). Studies have shown that high M r (100,000 -200,000 g/mol) glucans with a degree of branching of 0.20 -0.33 are most active (2), however, data describing the effects of molecular conformation on biological activity are less clear. This is in part due to the lack of adequate methodology to characterize the tertiary structure of glucans.Most spectroscopic techniques only provide data about the secondary structure of glucans. Methods such as solid state 13 C NMR spectroscopy (3) or multi-angle laser-light scattering (4) have had some success in relating the tertiary structure of glucans to their conformation based biological activity, however, their use is limited by availability, cost, and efficacy for evaluating glucan structure in solution. A direct observation technique, such as x-ray crystallography would assist in understanding glucan structure and its biological relevance; however, it is difficult to crystallize glucans and only a limited number of these studies have been done (5-7).Fluorescence resonance energy transfer (FRET) 1 is a phenomenon of non-radioactive energy transfer over relatively long distances that has been used to characterize the spatial relationship of donor-and acceptor-labeled molecules in biological systems (8). If a system contains two fluorophores an...

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“…5 ). However, the triple helix structure most likely should not be the sole effective form of β-glucan because alkalic treatment, used in most of isolation procedures, destroys this structure 6,7 . In addition, recent opinions do not confirm established ideas of the necessity of high molecular mass and branching of biologically active β-glucans.…”

mentioning

confidence: 99%

ANTI-STRESS ACTION OF SEVERAL ORALLY-GIVEN Β-Glucans

Větvička¹,

Vančíková²

2010

Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub

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Background. β−Glucans are well-established immunomodulators. Recently, glucans have been found to influence stress-related immunosuppression.Aim. The aim of this study was to compare the effects of four different types of β-glucans on immune reactions suppressed by cold-or restrain-induced stress.Methods. Mice were subjected to restraint and cold stress for various time intervals. The ability of individual glucans to overcome stress-related changes was evaluated after 14 days of feeding.Results. First, we showed that cold stress caused 38% decrease in phagocytic activity. While all glucans showed some ability to inhibit stress-related inhibition, only glucan #300 was able to return the phagocytosis to a normal level. In the control group, feeding with glucans did not alter the level of corticosterone. On the other hand, both types of stress resulted in a significant increase in corticosterone which was blocked to some extent by feeding with glucan. Both types of stress reduced IL-6 secretion but only glucan #300 managed to keep IL-6 secretion above control levels. The same results were obtained in the case of IL-12.Conclusion. From our data, we can conclude that, even when all orally-administered glucans helped to restore the stress-related decrease in immune reaction, the level of activity varied widely among individual glucans. In addition, the results suggest that glucans might work via inhibition of corticosterone levels and/or stimulation of cytokine production.

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Relationship between conformation and biological response for (1→3)-β-d-glucans in the activation of coagulation Factor G from limulus amebocyte lysate and host-mediated antitumor activity. Demonstration of single-helix conformation as a stimulant.

Cited by 153 publications

References 26 publications

Chemistry and Biology of Angiitis Inducer, Candida albicans Water‐Soluble Mannoprotein‐β‐Glucan Complex (CAWS)

Chemistry and Biology of Angiitis Inducer, Candida albicans Water‐Soluble Mannoprotein‐β‐Glucan Complex (CAWS)

Observation of a Partially Opened Triple-helix Conformation in 1→3-β-Glucan by Fluorescence Resonance Energy Transfer Spectroscopy

ANTI-STRESS ACTION OF SEVERAL ORALLY-GIVEN Β-Glucans

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