Atomic force microscopy imaging of carrageenans from red algae of Gigartinaceae and Tichocarpaceae families

Sokolova, E. V.; Chusovitin, E. A.; Barabanova, A. O.; Balagan, S. A.; Галкин, Н. Г.; Yermak, Irina M.

doi:10.1016/j.carbpol.2012.12.026

Cited by 36 publications

(28 citation statements)

References 25 publications

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“…The formation of the double helix structure suggests that lateral interactions between chains are taking place. In the case of a hybrid κ-ι-carrageenan, at low concentration (10 μg mL −1 ), the presence of both single-and twostranded structure was found by AFM (Sokolova et al 2013). Figure 7b-c shows the AFM phase image of copolymers obtained grafting acrylamide by conventional method into the a l k a l i -t r e a t e d p o l y s a c c h a r i d e f r o m c y s t o c a r p i c M. laminarioides (MCP-CAN) (Fig.…”

Section: Discussionmentioning

confidence: 95%

“…Phase AFM images were collected in air conditions at room temperature (24°C). Samples of both polysaccharide and synthesized graft copolymers for AFM study were prepared according to Sokolova (Sokolova et al 2013). Briefly, 5 mg of polymers was dissolved in 50 mL of ultrapure water, filtered through 0.22 μm GV EM PVDF Durapore (Millipore) filters, and deposited onto fresh cleaved mica surfaces.…”

Section: Copolymerization With Acrylamidementioning

confidence: 99%

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Carrageenans from nuclear phases of subantartic Mazzaella laminarioides (Gigartinales, Rhodophyta) and graft copolymerization of alkali-modified carrageenan with acrylamide

et al. 2015

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Aqueous extraction of cystocarpic, tetrasporic, and vegetative individuals of Mazzaella laminariodes collected in the Magellan Ecoregion, Southern Chile, afforded sulfated galactans. Analysis by Fourier transform infrared spectroscopy (FT-IR) and by 1 H and 13 C NMR spectroscopy indicated that purified extracts from cystocarpic (CP) and vegetative individuals (VP) were mixtures of κ/ι-type carrageenans and their precursors μ-and ν-carrageenans, whereas the aqueous extract from tetrasporic individuals was a λ-type carrageenan. Alkaline treatment of CP and VP polysaccharides produced modified polysaccharides with lower content of sulfate groups and with a concomitant increase of 3,6-anhydrogalactose content; analysis by 2D 1 H and 13 C NMR indicated the presence of hybrid κ-ι-carrageenans. Copolymerization of alkalitreated CP carrageenan with acrylamide was achieved by using ceric ammonium nitrate as the initiator; studies by NMR spectroscopy indicated grafting of polyacrylamide at position C-6 of β-galactopyranosyl residues. Reaction of modified CP with acrylamide assisted by microwave irradiation in the presence of ammonium persulfate afforded a copolymer grafted at position C-2 of β-galactopyranosyl residues.

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Section: Discussionmentioning

confidence: 95%

Section: Copolymerization With Acrylamidementioning

confidence: 99%

Carrageenans from nuclear phases of subantartic Mazzaella laminarioides (Gigartinales, Rhodophyta) and graft copolymerization of alkali-modified carrageenan with acrylamide

et al. 2015

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“…These data suggest the presence of nonspecific interaction between the LPS and the carrageenans with low sulphate content (kappa and kappa/ beta). LPS can be integrated into highly ordered ultrastructures of kappa-and kappa/beta-carrageenans which they form due to the presence of 3,6-anhydrogalactose unit (Sokolova et al 2013). In the case of lambda-carrageenan, similar changes in the LPS structure were not observed.…”

Section: Discussionmentioning

confidence: 98%

Influence of red algal polysaccharides on biological activities and supramolecular structure of bacterial lipopolysaccharide

et al. 2015

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The present work reveals the effect of kappa-, lambda-and kappa/beta-carrageenans on the immune modulation and supramolecular structure of lipopolysaccharide (LPS). The kappa/beta carrageenan was able to increase the synthesis of anti-inflammatory interleukin-10 (IL-10) in vitro, and at low concentrations, their activity in the mixture with LPS was higher than that of LPS alone. Kappa-carrageenan significantly inhibited LPS-induced upregulation of reactive oxygen species (ROS). The activation of cells by kappa-carrageenan occurs through TLR4 receptor specific for LPS. Carrageenans reduced (kappa-) or completely inhibited (lambda-) collageninduced platelet aggregation and decreased their aggregation activity caused by cooperative effect of LPS and collagen. The transformation of ultrastructure of LPS by action of kappa-and kappa/beta-carrageenans is observed. Moreover, carrageenans changed both the sizes and ζ-potentials of the LPS.

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“…3(a), area (1)) with epitaxial relations: hR6-CaSi2[100]||Si [1][2][3][4][5][6][7][8][9][10] and hR6-CaSi2(001)||Si(111). The identification of the SA FFT pattern for area (1) results in the un-defective CaSi2 layer growth on Si(111)7x7 surface without stacking faults in 3-4 unit cell thickness.…”

Section: Resultsmentioning

confidence: 99%

“…Atomic force microscopy (AFM) images were analyzed with "Calculating of Average Parameters of Objects on Surface" software [10].…”

Section: Methodsmentioning

confidence: 99%

Epitaxial relations, crystalline structure and defects in the double Si(111)/hR6 CaSi₂/Si(111) heterostructures

Галкин¹,

Dotsenko²,

Galkin³

et al. 2017

Proc. Asia-Pacific Conf. On Semiconducting Silicides and Related Materials 2016

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The morphology and crystalline structure of Si(111)/CaSi2/Si(111) double heterostructures (DHS) formed by the Ca reactive deposition epitaxy on the Si(111)7x7 surface and Si overgrowth at 500 o C have been studied by atomic force microscopy and transmission electron microscopy. It was established that stressed CaSi2 layers with stacking faults in (001)CaSi2 plane and {111}-twinned epitaxial or polycrystalline Si layers were grown. Epitaxial Si layers while had orientation parallel to the Si(111) substrate surface. CaSi2[100]||Si[1-10] and CaSi2(001)||Si(111) epitaxial relations were conserved for all grown DHS and they did not depend from the silicon growth mode: molecular beam epitaxy (MBE) or solid phase epitaxy (SPE). The CaSi2 layer in (001)CaSi2 plane has a hR6 modification and parameters: a=0.393±0.002 nm; c=3.09±0.18 nm at SPE Si growth mode. But some another parameters: a=0.382±0.002 nm; c=3.09 ±0.18 nm were observed at MBE Si growth mode. The compression in c parameter on near 1.07-1.14% as compared with c-value (3.06 nm) for tabular CaSi2 data is established fact for both HDS. The observed differences in a parameter +1.85% (at SPE mode) and -1.08% (at MBE mode) is not clear now, and demands additional experiments. Some assumptions about mechanisms of occurrence and distribution of compressions and stretching in the CaSi2 lattice were made.

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Atomic force microscopy imaging of carrageenans from red algae of Gigartinaceae and Tichocarpaceae families

Cited by 36 publications

References 25 publications

Carrageenans from nuclear phases of subantartic Mazzaella laminarioides (Gigartinales, Rhodophyta) and graft copolymerization of alkali-modified carrageenan with acrylamide

Carrageenans from nuclear phases of subantartic Mazzaella laminarioides (Gigartinales, Rhodophyta) and graft copolymerization of alkali-modified carrageenan with acrylamide

Influence of red algal polysaccharides on biological activities and supramolecular structure of bacterial lipopolysaccharide

Epitaxial relations, crystalline structure and defects in the double Si(111)/hR6 CaSi₂/Si(111) heterostructures

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Atomic force microscopy imaging of carrageenans from red algae of Gigartinaceae and Tichocarpaceae families

Cited by 36 publications

References 25 publications

Carrageenans from nuclear phases of subantartic Mazzaella laminarioides (Gigartinales, Rhodophyta) and graft copolymerization of alkali-modified carrageenan with acrylamide

Carrageenans from nuclear phases of subantartic Mazzaella laminarioides (Gigartinales, Rhodophyta) and graft copolymerization of alkali-modified carrageenan with acrylamide

Influence of red algal polysaccharides on biological activities and supramolecular structure of bacterial lipopolysaccharide

Epitaxial relations, crystalline structure and defects in the double Si(111)/hR6 CaSi2/Si(111) heterostructures

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Epitaxial relations, crystalline structure and defects in the double Si(111)/hR6 CaSi₂/Si(111) heterostructures