Structural and functional properties of mouse proNGF

2006 ◽  
Vol 34 (4) ◽  
pp. 605-606 ◽  
Author(s):  
F. Paoletti ◽  
P.V. Konarev ◽  
S. Covaceuszach ◽  
E. Schwarz ◽  
A. Cattaneo ◽  
...  
Keyword(s):  
Structural Determinants ◽  
Compact Structure ◽  
X Ray ◽  
Neurotrophic Activity ◽  
X Ray Scattering ◽  
Structural And Functional Properties ◽  
Physicochemical Methods ◽  
Pro Region

The unprocessed pro-form of the NGF (nerve growth factor), proNGF (NGF precursor, without signal peptide), has been suggested to have additional functions distinct from its role as a promoter of protein folding, i.e. apoptosis and/or neurotrophic activity. Aiming to gain insights into the specific molecular interactions that mediate proNGF biological activity and into the structural determinants stabilizing its pro-region, rm-proNGF (recombinant mouse proNGF) was expressed in Escherichia coli, refolded in vitro and characterized by physicochemical methods. X-ray solution scattering measurements (small angle X-ray scattering) revealed that rm-proNGF is dimeric in solution and appears to be anisometric when compared with the compact structure of the NGF dimer. Two structural models, a globular crab-like shape and an elongated rod-like shape, equally fit to the experimental results, pointing to an intrinsically structural disordered pro-region of NGF. The models obtained allowed the interpretation of TrkA (tropomyosin receptor kinase A) binding and activation assays in cell cultures, shedding new light on the key role of proNGF in neuronal survival and neurodegeneration.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

Time-Resolved Cryo-Electron Microscopy of Oscillating Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 502-503
Author(s):  
Eva-Maria Mandelkow ◽  
Ron Milligan
Keyword(s):  
Electron Microscopy ◽  
Dynamic Instability ◽  
Entire Solution ◽  
Reaction Scheme ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
A Chain ◽  
Ray Scattering

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?

scholarly journals Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealing

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Fausta Loffredo ◽  
Loredana Tammaro ◽  
Tiziana Di Luccio ◽  
Carmela Borriello ◽  
Fulvia Villani ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Structural Evolution ◽  
Tungsten Disulfide ◽  
Fine Tuning ◽  
Nanocomposite Films ◽  
Uniaxial Deformation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering

AbstractTungsten disulfide (WS2) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS2 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS2 nanocomposite films varying the concentration of WS2 NTs from 0 (neat PLA) to 0.6 wt%. The films were uniaxially drawn at 90 °C and annealed at the same temperature for 3 and 10 min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS2 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6 wt% of WS2 induces the same level of crystallinity in as stretched PLA-WS2 as annealing in neat PLA for 10 min. These data provide useful insights into the role of WS2 NTs on the structural evolution of PLA-WS2 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.

scholarly journals Polymorphic Protective Dps–DNA Co-Crystals by Cryo Electron Tomography and Small Angle X-Ray Scattering

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 39 ◽  
Author(s):  
Roman Kamyshinsky ◽  
Yury Chesnokov ◽  
Liubov Dadinova ◽  
Andrey Mozhaev ◽  
Ivan Orlov ◽  
...  
Keyword(s):  
Small Angle ◽  
Electron Tomography ◽  
Actual Structure ◽  
X Ray ◽  
Cell Parameters ◽  
X Ray Scattering ◽  
Cryo Electron Tomography ◽  
Dps Protein ◽  
Ray Scattering

Rapid increase of intracellular synthesis of specific histone-like Dps protein that binds DNA to protect the genome against deleterious factors leads to in cellulo crystallization—one of the most curious processes in the area of life science at the moment. However, the actual structure of the Dps–DNA co-crystals remained uncertain in the details for more than two decades. Cryo-electron tomography and small-angle X-ray scattering revealed polymorphous modifications of the co-crystals depending on the buffer parameters. Two different types of the Dps–DNA co-crystals are formed in vitro: triclinic and cubic. Three-dimensional reconstruction revealed DNA and Dps molecules in cubic co-crystals, and the unit cell parameters of cubic lattice were determined consistently by both methods.

scholarly journals Protective Dps–DNA co‐crystallization in stressed cells: an in vitro structural study by small‐angle X‐ray scattering and cryo‐electron tomography

FEBS Letters ◽  
2019 ◽  
Vol 593 (12) ◽  
pp. 1360-1371 ◽  
Author(s):  
Liubov A. Dadinova ◽  
Yurii M. Chesnokov ◽  
Roman A. Kamyshinsky ◽  
Ivan A. Orlov ◽  
Maxim V. Petoukhov ◽  
...  
Keyword(s):  
Structural Study ◽  
Small Angle ◽  
Electron Tomography ◽  
X Ray ◽  
X Ray Scattering ◽  
Cryo Electron Tomography ◽  
Stressed Cells ◽  
Ray Scattering

scholarly journals Resonant Inelastic X-ray Scattering on Ferrous and Ferric Bis-imidazole Porphyrin and Cytochromec: Nature and Role of the Axial Methionine–Fe Bond

2014 ◽  
Vol 136 (52) ◽  
pp. 18087-18099 ◽  
Author(s):  
Thomas Kroll ◽  
Ryan G. Hadt ◽  
Samuel A. Wilson ◽  
Marcus Lundberg ◽  
James J. Yan ◽  
...  
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Prominent role of oxygen in the multiferroicity ofDyMnO3andTbMnO3: A resonant soft x-ray scattering spectroscopy study

2016 ◽  
Vol 94 (3) ◽  
Author(s):  
S. W. Huang ◽  
J. M. Lee ◽  
Horng-Tay Jeng ◽  
YuCheng Shao ◽  
L. Andrew Wray ◽  
...  
Keyword(s):  
Spectroscopy Study ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Effects of dietary alteration of bicarbonate and magnesium on rat bone

1986 ◽  
Vol 250 (2) ◽  
pp. F302-F307 ◽  
Author(s):  
J. M. Burnell ◽  
C. Liu ◽  
A. G. Miller ◽  
E. Teubner
Keyword(s):  
Crystal Structure ◽  
Bone Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Growing Rats ◽  
Final Composition ◽  
Rat Bone

To study the effects of bicarbonate and magnesium on bone, mild acidosis and/or hypermagnesemia were produced in growing rats by feeding ammonium chloride and/or magnesium sulfate. Bone composition, quantitative histomorphometry, and mineral x-ray diffraction (XRD) characteristics were measured after 6 wk of treatment. The results demonstrated that both acidosis (decreased HCO3) and hypermagnesemia inhibited periosteal bone formation, and, when combined, results were summative; and the previously observed in vitro role of HCO3- and Mg2+ as inhibitors of crystal growth were confirmed in vivo. XRD measurements demonstrated that decreased plasma HCO3 resulted in larger crystals and increased Mg resulted in smaller crystals. However, the combined XRD effects of acidosis and hypermagnesemia resembled acidosis alone. It is postulated that the final composition and crystal structure of bone are strongly influenced by HCO3- and Mg2+, and the effects are mediated by the combined influence on both osteoblastic bone formation and the growth of hydroxyapatite.

scholarly journals Decellularized pericardium tissues at increasing glucose, galactose and ribose concentrations and at different time points studied using scanning X-ray microscopy

IUCrJ ◽  
2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Cinzia Giannini ◽  
Liberato De Caro ◽  
Alberta Terzi ◽  
Luca Fusaro ◽  
Davide Altamura ◽  
...  
Keyword(s):  
Molecular Level ◽  
Wide Angle ◽  
Collagen Structure ◽  
Tissue Samples ◽  
X Ray ◽  
X Ray Scattering ◽  
Aging Populations ◽  
Secondary Diseases

Diseases like widespread diabetes or rare galactosemia may lead to high sugar concentrations in the human body, thereby promoting the formation of glycoconjugates. Glycation of collagen, i.e. the formation of glucose bridges, is nonenzymatic and therefore cannot be prevented in any other way than keeping the sugar level low. It relates to secondary diseases, abundantly occurring in aging populations and diabetics. However, little is known about the effects of glycation of collagen on the molecular level. We studied in vitro the effect of glycation, with D-glucose and D-galactose as well as D-ribose, on the structure of type 1 collagen by preparing decellularized matrices of bovine pericardia soaked in different sugar solutions, at increasing concentrations (0, 2.5, 5, 10, 20 and 40 mg ml−1), and incubated at 37°C for 3, 14, 30 and 90 days. The tissue samples were analyzed with small- and wide-angle X-ray scattering in scanning mode. We found that glucose and galactose produce similar changes in collagen, i.e. they mainly affect the lateral packing between macromolecules. However, ribose is much faster in glycation, provoking a larger effect on the lateral packing, but also seems to cause qualitatively different effects on the collagen structure.

scholarly journals Etude Des Effets Des Régulateurs De Croissance Sur La Les Stades De Prolifération Et De Développement De La Pomme De Terre (Solanum Tuberosum. L) In Vitro

2017 ◽  
Vol 13 (24) ◽  
pp. 145
Author(s):  
Sadek Chahredine ◽  
Nadia Ykhlef
Keyword(s):  
Solanum Tuberosum ◽  
Callus Induction ◽  
Solanum Tuberosum L ◽  
Naphthaleneacetic Acid ◽  
Compact Structure ◽  
Potato Plants ◽  
Régulateurs De Croissance ◽  
Role Of Light

The aim of this study is to determine the effects of different concentrations and combinations of the phytohormones, 1-naphthaleneacetic acid (NAA), and 6-benzylaminopurine (BAP): M1 (0.5 mg / l +1 mg / l), M2 (1 mg / l + 0.5 mg / l) , M3 (2 mg / l +2 mg / l), M4 (0.5 mg / l + l mg / l, NAA), M5 (1.0 mg / l + l mg / l , NAA), and M6 (2.0 mg / l + l mg / l, NAA). This study was carried out in dark condition on callus induction of potato plants (Solanum tuberosum L.) cultivars from potato tuber bud so as to demonstrate the role of light. The callus initiation begins after 7 days of incubation for all studied media. After two months of incubation, the better development of callus was noted in Spunta variety by using medium M1, M2, M3, and M6. The calluses took a compact structure of brown-white color for both varieties with a callus induction rate of 20- 40%. This was collected with kondor variety for M2 and (M3, M4, M5) media respectively and 10-30% for M4 (M1, M2, M3) for Spunta variety also. The highest fresh weight was recorded on M2 medium with 0.26g for Kondor variety and 0.93g for Spunta variety.

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