Additional Investigation of Earthquakes with Low M sub s to m sub b Ratios in the Tibet-Himalaya Region

Clark, Don M; Sweetser, E.I.; Der, Zoltan A.

doi:10.21236/ada023949

Cited by 5 publications

(13 citation statements)

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“…The presence ofmassive amounts of competitive glycerate-2,3-P2 and ATP in the cytoplasm should certainly exclude a significant binding of Hb in the normal mature red blood cell. However, since senescence in red blood cells appears to be associated with a decrease in metabolic activity [40] one can envisage that a partial depletion of glycerate-2,3-P2 and ATP could make the conditions favorable for a small fraction of organic-anion-depleted Hb to bind the protofilaments of actin in the skeleton and promote their instability, thus accelerating the destruction of the cell. The ability to prepare intact red blood cell cytoskeletons makes this hypothesis accessible for experimentation.…”

Section: Discussionmentioning

confidence: 99%

Interactions of actin and tubulin with human deoxyhemoglobin

Lebbar

Stetzkowski‐Marden

Mauffret

et al. 1987

European Journal of Biochemistry

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Short actin filaments are an essential component of the red-cell membrane skeleton, and microtubules are also present in nucleated erythrocytes as a marginal band. Actin and tubulin share the property of possessing a very anionic terminal peptide. Since deoxyhemoglobin (Hb) is known to be a strong polyanion-binding protein, we have considered how it may interact with actin and tubulin within the intact cell. Here we demonstrate that actin and tubulin form in vitro a high-affinity complex with Hb. This is shown by measuring, by stopped-flow experiments, the decrease of the binding rate constant of CO to Hb in the presence of increasing amounts of actin and tubulin. One tetramer of Hb is bound by an actin monomer, and about two tetramers by an a$-tubulin heterodimer. Binding assays in batch experiments with immobilized tubulin give the same stoichiometry. Formation of the complexes involves the 2,3-bisphosphoglycerate-binding site of Hb and a negatively charged domain, most likely the highly acidic N and C-terminal peptides of actin and tubulin. In addition to providing new opportunities to study the structural and functional properties of actin and tubulin, these results support the idea that in the case of partial metabolic depletion of bisphosphoglycerate and ATP in erythrocytes, Hb may interact with oligomeric actin and tubulin present in the cytoskeleton.Human deoxyhemoglobin (Hb) is certainly one of the bestcharacterized polyanion-binding proteins [l, 21, considering the role of 2,3-bisphosphoglycerate (glycerate-2,3-P2) as the natural effector of its oxygen affinity [3]. X-ray analyses have given explicit details on the interaction between glycerate-2,3-P2 and the cationic amino acid residues involved in the /? chain of the Hb tetramer [2]. In the red cells of the venous blood massive amounts of fully or partially deoxygenated hemoglobin are engaged, in competition with other cationic molecules, in multiple equilibria with several anions, in addition to the millimolar amounts of glycerate-2,3-P2 [4, 51. Some of these polyanions may be localized in the vicinity of the plasmic membrane as suggested by recent evidence indicating that Hb binds within erythrocytes with the highly acidic N-terminus Met-Glu-Glu-Leu-Gln-Asp-Asp-Tyr-GluAsp-Asp-of the cytoplasmic domain of band 3, the aniontransport protein of the erythrocyte membrane [6 -81 (for review see [9]). The red cell membrane skeleton contains short actin filaments (protofilaments) interconnected with spectrin tetramers to constitute a flexible meshwork of proteins underlying the plasmic membrane [lo]. This structure is further reinforced in the nucleated erytrocyte with the presence of a marginal band constituted of a bundle of microtubules [l 11. Actin and tubulin are known to possess, as band 3, a very acidic N and C-terminal peptide invariably represented by a combination of aspartic and glutamic residues. This sequence for muscle actin is Asp-Glu-Asp-Glu-and it is -Glu-Glu-GluGly-Glu-Glu-(Tyr) and -Glu-Glu-Glu-Gly-Glu-Glu-Asp-Glu- In erythrocytes they c...

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Section: Discussionmentioning

confidence: 99%

Interactions of actin and tubulin with human deoxyhemoglobin

Lebbar

Stetzkowski‐Marden

Mauffret

et al. 1987

European Journal of Biochemistry

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“…After the third transition, the majority of the bands with small wavenumbers become indistinguishable against the noise background (Figs 2 and 5). These modes (with one exception discussed in the following) are the external vibrations of ionicmolecular groups, namely, Si(OH) 6 , SO 4 , СО 3 , and H 2 O, and the translational vibrations of Ca cations. We assume that the weakening of the intensity of the lattice modes with pressure provides an indication for orientational disordering in these groups.…”

Section: Resultsmentioning

confidence: 97%

“…The wavenumber of the intense Raman band due to the ν 1 Si-O symmetric stretching vibrations of the Si(OH) 6 group at 660 cm À1 almost linearly increases with pressure in phase I, and after the I-II transition, which occurs at 4.4 GPa, this wavenumber shows no subsequent changes (Fig. 5).…”

Section: Resultsmentioning

confidence: 99%

“…Then, the satellite vanishes, and another satellite, shifted in wavenumber down to 631 cm À1 and being three times broader than the former satellite, emerges. Most likely, these satellites can be assigned to Si-O stretching vibrations of Si(OH) 6 groups, which sense the pressure-induced variation of the length of hydrogen bonds in specimens under high pressure Р.…”

Section: Resultsmentioning

confidence: 99%

“…Thaumasite is often formed in concretes because of the reactions proceeding between calcium silicates, carbonates, and sulfates. [1,2,[6][7][8] Along with other hydrated silicates, thaumasite may form during cementation under sulfate attack conditions, especially at low temperatures (0 to À40°С). [8,9] During heating in air at 144°С, thaumasite decomposes with the loss of water and with the formation of an amorphous water-free phase.…”

Section: Introductionmentioning

confidence: 99%

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Raman study of thaumasite Ca₃Si(OH)₆(SO₄)(CO₃)⋅12H₂O at high pressure

Goryaĭnov

2016

J Raman Spectroscopy

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Thaumasite, Ca3Si(OH)6(SO4)(CO3)⋅12H2O, is an extraordinary mineral that possibly plays a special role in the carbonate–sulfate–silicate balance of the Earth's crust. Thaumasite, an undesirable component in concrete, remains a material poorly studied at high pressures in various media except for He medium (M. Ardit et al., Mineral. Mag., 2014). In the present Raman study, thaumasite samples were compressed in alcohol–water and KBr media at high pressures up to ~7 GPa: several phase transformations were identified. In samples compressed in alcohol–water, the wavenumbers of intense Raman bands of SO and СО symmetric stretching vibrations at 991 and 1074 cm−1 proved to exhibit similar dependences on pressure: during a first transition I → II at 4.4 GPa, the wavenumbers of both bands exhibited a downward jump; at a second transition II → III, which occurred at 4.9 GPa, each band split in a doublet; and then, at a third transition III → IV, which was observed at 5.4 GPa, each doublet band transformed in a singlet. In KBr medium, these and other Raman bands of thaumasite showed similar (to those in thaumasite at compression in alcohol–water) dependences on pressure, revealing several phase transitions with slightly shifted transition points, the first transition I → II, however, being not distinguished. Taking into account the similar behaviors in both media, the transitions are assumed to be polymorphic: no noticeable overhydration in thaumasite compressed in water–alcohol occurred. In phase IV, gradual widening and weakening of each band were observed; those changes can be attributed to amorphization of the material. Considerable hysteresis was observed at thaumasite decompression. Copyright © 2016 John Wiley & Sons, Ltd.

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High Electron Mobility of Amorphous Red Phosphorus Thin Films

et al. 2019

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Black phosphorus (BP) has been gathering great attention for its electronic and optoelectronic applications due to its high electron mobility and high ION/OFF current switching ratio. The limitations of this material include its low synthetic yield and high cost. One alternative to BP is another type of phosphorus allotrope, red phosphorus (RP), which is much more affordable and easier to process. Although RP has been widely used in industry for hundreds of years and considered as an insulating material, in this study, we demonstrate through field‐effect transistors (FET) measurements that amorphous red phosphorus (a‐RP) films are semiconductive with a high mobility of 387 cm2 V−1 s−1 and a current switching ratio of ≈103, which is comparable to the electronic characteristics previously reported for BP. The films were produced via a thermal evaporation method or a facile drop‐casting approach onto Si/SiO2 substrates. We also report a study of the oxidation process of the films over time and a method to stabilize the films via doping a‐RP with metal oxides. The doped films retain stability for one thousand I–V cycles, with no signs of degradation.

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Additional Investigation of Earthquakes with Low M sub s to m sub b Ratios in the Tibet-Himalaya Region

Cited by 5 publications

References 0 publications

Interactions of actin and tubulin with human deoxyhemoglobin

Interactions of actin and tubulin with human deoxyhemoglobin

Raman study of thaumasite Ca₃Si(OH)₆(SO₄)(CO₃)⋅12H₂O at high pressure

High Electron Mobility of Amorphous Red Phosphorus Thin Films

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Additional Investigation of Earthquakes with Low M sub s to m sub b Ratios in the Tibet-Himalaya Region

Cited by 5 publications

References 0 publications

Interactions of actin and tubulin with human deoxyhemoglobin

Interactions of actin and tubulin with human deoxyhemoglobin

Raman study of thaumasite Ca3Si(OH)6(SO4)(CO3)⋅12H2O at high pressure

High Electron Mobility of Amorphous Red Phosphorus Thin Films

Contact Info

Product

Resources

About

Raman study of thaumasite Ca₃Si(OH)₆(SO₄)(CO₃)⋅12H₂O at high pressure