scholarly journals Rouse model with transient intramolecular contacts on a timescale of seconds recapitulates folding and fluctuation of yeast chromosomes

2019 ◽  
Vol 47 (12) ◽  
pp. 6195-6207 ◽  
Author(s):  
Marius Socol ◽  
Renjie Wang ◽  
Daniel Jost ◽  
Pascal Carrivain ◽  
Cédric Vaillant ◽  
...  
Keyword(s):  
Structural Properties ◽  
Single Particle Tracking ◽  
Chemical Parameters ◽  
Chromosome Conformation ◽  
Formation Reaction ◽  
Rouse Model ◽  
Physico Chemical ◽  
Capture Techniques

Abstract DNA folding and dynamics along with major nuclear functions are determined by chromosome structural properties, which remain, thus far, elusive in vivo. Here, we combine polymer modeling and single particle tracking experiments to determine the physico-chemical parameters of chromatin in vitro and in living yeast. We find that the motion of reconstituted chromatin fibers can be recapitulated by the Rouse model using mechanical parameters of nucleosome arrays deduced from structural simulations. Conversely, we report that the Rouse model shows some inconsistencies to analyze the motion and structural properties inferred from yeast chromosomes determined with chromosome conformation capture techniques (specifically, Hi-C). We hence introduce the Rouse model with Transient Internal Contacts (RouseTIC), in which random association and dissociation occurs along the chromosome contour. The parametrization of this model by fitting motion and Hi-C data allows us to measure the kinetic parameters of the contact formation reaction. Chromosome contacts appear to be transient; associated to a lifetime of seconds and characterized by an attractive energy of –0.3 to –0.5 kBT. We suggest attributing this energy to the occurrence of histone tail-DNA contacts and notice that its amplitude sets chromosomes in ‘theta’ conditions, in which they are poised for compartmentalization and phase separation.

Chiral Forms of 4-(2',4'-Difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic Acid (Flobufen) and Its Metabolite.Synthesis and Basic Biological Properties

1997 ◽  
Vol 62 (3) ◽  
pp. 498-509 ◽  
Author(s):  
Miroslav Kuchař ◽  
Marie Poppová ◽  
Antonín Jandera ◽  
Vladimíra Panajotovová ◽  
Hana Zůnová ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Biological Activities ◽  
Biological Properties ◽  
Optical Isomers ◽  
Clinical Testing ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Oxobutanoic Acid

4-(2',4'-Difluorobiphenyl-4-yl)-2-methyl-4-oxobutanoic acid (1, flobufen) is subjected to clinical testing in the treatment of rheumatoid arthritis. Owing to the occurrence of a centre of chirality, the compound exists in two enantiomers, and its major human metabolite, viz. 4-(2',4'-difluorobiphenyl-4-yl)-4-hydroxy-2-methylbutanoic acid isolated in the lactone form (2), possesses two chiral centres, making possible the existence of four stereoisomers. All of the optical isomers of the substances 1 and 2 were prepared. For flobufen (1), the racemate was separated into the stereoisomers by using the salts 3 with R-(+)- or S-(-)-1-phenylethylamine. The pairs of stereoisomers of 2, obtained by reduction of R-(+)-flobufen or the S-(-)-enantiomer, were separated by column chromatography. The physico-chemical parameters of the optical isomers were determined and some biological activities were evaluated in both in vitro and in vivo models.

scholarly journals Cartwright's method as a physico-chemical marker of antimonium crudum biological effect

2021 ◽  
Vol 17 (2) ◽  
pp. 14-14
Author(s):  
Hannah MG Mota ◽  
Ana Carla Aparicio ◽  
Larissa Helen Silva Oliveira ◽  
Renata Rossettini Palombo Pedro ◽  
Sandra AG Pinto ◽  
...  
Keyword(s):  
Biological Effects ◽  
Electric Signal ◽  
Chemical Marker ◽  
Chemical Parameters ◽  
Monocyte Migration ◽  
Physico Chemical ◽  
Methylene Violet ◽  
One Way Anova

Mice bearing Leishmania (L) amazonensis infection and treated with Antimonium crudum (AC) 30cH presented significant reduction of the monocyte migration to the site of infection with clinical improvement. In vitro, the treatment of infected macrophages with AC 30cH produced inhibition of the parasite-induced peaks of CCL2 (a chemokine for monocytes migration) and inhibition of lysosome activity, explaining the results obtained previously in vivo. In the following studies, physical-chemical parameters of the remedy and respective controls were evaluated, to search for a correlation with the former described biological effects. The study of polarity changes in different water-based dilutions of AC using Cartwright´s method, revealed dilution-dependent variations in the absorbance of three solvatochromic dyes ET 33, BDN and methylene Violet (MV), used as “probes” to evaluate the dipole features of the medicine. The electrical activity of the homeopathic preparations appears to be dilution-dependent and related to their biological effects. Further experiments were performed using samples of the supernatant of infected macrophages after 96 hours of incubation with AC in different dilutions. These samples were processed using the same procedures as used for the original medicines and were analyzed by MV method. All tested potencies presented a sharp increase of absorbance at 580 nm, in relation to all controls (supernatant from untreated cells and cells treated with succussed water), as performed by one-way ANOVA, being F = 176.208; p = 0.001 and ?2 = 0.988. This results strongly suggest that biological systems could amplify the electric signal and the following changes in the medium polarity.

THYROID STIMULATORS AND THYROID STIMULATION

1971 ◽  
Vol 66 (3) ◽  
pp. 558-576 ◽  
Author(s):  
Gerald Burke
Keyword(s):  
Regulatory System ◽  
Control Site ◽  
Thyroid Cell ◽  
Primary Control ◽  
Physico Chemical ◽  
Site Of Action ◽  
Long Acting

ABSTRACT A long-acting thyroid stimulator (LATS), distinct from pituitary thyrotrophin (TSH), is found in the serum of some patients with Graves' disease. Despite the marked physico-chemical and immunologic differences between the two stimulators, both in vivo and in vitro studies indicate that LATS and TSH act on the same thyroidal site(s) and that such stimulation does not require penetration of the thyroid cell. Although resorption of colloid and secretion of thyroid hormone are early responses to both TSH and LATS, available evidence reveals no basic metabolic pathway which must be activated by these hormones in order for iodination reactions to occur. Cyclic 3′, 5′-AMP appears to mediate TSH and LATS effects on iodination reactions but the role of this compound in activating thyroidal intermediary metabolism is less clear. Based on the evidence reviewed herein, it is suggested that the primary site of action of thyroid stimulators is at the cell membrane and that beyond the(se) primary control site(s), there exists a multifaceted regulatory system for thyroid hormonogenesis and cell growth.

Mining a Nanoparticle Dataset, Compiled Within the MODENA-COST Action

2021 ◽  
pp. 1706-1724
Author(s):  
Sabine Van Miert ◽  
Jan Creylman ◽  
Geert R. Verheyen
Keyword(s):  
Chemical Properties ◽  
In Vitro Testing ◽  
Cost Action ◽  
Robust Model ◽  
Physico Chemical ◽  
Classification And Regression ◽  
Toxic Potential ◽  
Sheer Number

Engineered nanomaterials (ENM) have new or enhanced physico-chemical properties compared to their micron-sized counterparts, but may also have an increased toxic potential. Animal and in vitro testing are typically employed to investigate the toxic effects of (nano)materials. The sheer number of ENMs and their physico-chemical parameters make it impossible to only use in vivo and in vitro testing, and modelling technologies are also deployed to find relationships between ENM parameters and toxicity. A heterogenous dataset containing information on 192 nanoparticle endpoints was compiled within the MODENA COST-Action consortium. Here, the available data was mined to identify relationships between nanoparticle properties and cell-death as measured with four cytotoxicity assays. ANOVA, collinearity analyses and classification and regression trees gave indications on potential relations between the NP-properties and toxicity, but could not deliver a robust model. More information and datapoints are necessary to build well-validated models.

scholarly journals In Vitro Physico-Chemical Characterization and Standardized In Vivo Evaluation of Biocompatibility of a New Synthetic Membrane for Guided Bone Regeneration

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1186
Author(s):  
Lívia da Costa Pereira ◽  
Carlos Fernando de Almeida Barros Mourão ◽  
Adriana Terezinha Neves Novellino Alves ◽  
Rodrigo Figueiredo de Brito Resende ◽  
Marcelo José Pinheiro Guedes de Uzeda ◽  
...  
Keyword(s):  
Bone Regeneration ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Guided Bone Regeneration ◽  
Tissue Reaction ◽  
In Vivo Evaluation ◽  
Physico Chemical ◽  
Tissue Reactions

This study’s aim was to evaluate the biocompatibility and bioabsorption of a new membrane for guided bone regeneration (polylactic-co-glycolic acid associated with hydroxyapatite and β-tricalcium phosphate) with three thicknesses (200, 500, and 700 µm) implanted in mice subcutaneously. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and the quantification of carbon, hydrogen and nitrogen were used to characterize the physico-chemical properties. One hundred Balb-C mice were divided into 5 experimental groups: Group 1—Sham (without implantation); Group 2—200 μm; Group 3—500 μm; Group 4—700 μm; and Group 5—Pratix®. Each group was subdivided into four experimental periods (7, 30, 60 and 90 days). Samples were collected and processed for histological and histomorphometrical evaluation. The membranes showed no moderate or severe tissue reactions during the experimental periods studied. The 500-μm membrane showed no tissue reaction during any experimental period. The 200-μm membrane began to exhibit fragmentation after 30 days, while the 500-μm and 700-µm membranes began fragmentation at 90 days. All membranes studied were biocompatible and the 500 µm membrane showed the best results for absorption and tissue reaction, indicating its potential for clinical guided bone regeneration.

scholarly journals Optimization of Innovative Three-Dimensionally-Structured Hybrid Vesicles to Improve the Cutaneous Delivery of Clotrimazole for the Treatment of Topical Candidiasis

Pharmaceutics ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 263 ◽  
Author(s):  
Maria Letizia Manca ◽  
Iris Usach ◽  
José Esteban Peris ◽  
Antonella Ibba ◽  
Germano Orrù ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Yeast Cells ◽  
Unilamellar Vesicles ◽  
Transmission Electron ◽  
Physico Chemical

New three-dimensionally-structured hybrid phospholipid vesicles, able to load clotrimazole in a high amount (10 mg/mL), were obtained for the first time in this work by significantly reducing the amount of water (≤10%), which was replaced with a mixture of glycerol and ethanol (≈90%). A pre-formulation study was carried out to evaluate the effect of both the composition of the hydrating medium and the concentration of the phospholipid on the physico-chemical properties of hybrid vesicles. Four different three-dimensionally-structured hybrid vesicles were selected as ideal systems for the topical application of clotrimazole. An extensive physico-chemical characterization performed using transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), 31P-NMR, and small-angle X-ray scattering (SAXS) displayed the formation of small, multi-, and unilamellar vesicles very close to each other, and was capable of forming a three-dimensional network, which stabilized the dispersion. Additionally, the dilution of the dispersion with water reduced the interactions between vesicles, leading to the formation of single unilamellar vesicles. The evaluation of the in vitro percutaneous delivery of clotrimazole showed an improved drug deposition in the skin strata provided by the three-dimensionally-structured vesicles with respect to the commercial cream (Canesten®) used as a reference. Hybrid vesicles were highly biocompatible and showed a significant antifungal activity in vitro, greater than the commercial cream Canesten®. The antimycotic efficacy of formulations was confirmed by the reduced proliferation of the yeast cells at the site of infection in vivo. In light of these results, clotrimazole-loaded, three-dimensionally-structured hybrid vesicles appear to be one of the most innovative and promising formulations for the treatment of candidiasis infections.

Thermodynamic and structural properties of tuber starches from transgenic potato plants grown in vitro and in vivo

2015 ◽  
Vol 125 ◽  
pp. 214-223 ◽  
Author(s):  
Luybov A. Wasserman ◽  
Andrey I. Sergeev ◽  
Viktor G. Vasil’ev ◽  
Irina G. Plashchina ◽  
Nina P. Aksenova ◽  
...  
Keyword(s):  
Structural Properties ◽  
Transgenic Potato ◽  
Potato Plants ◽  
Transgenic Potato Plants

Natural Poly(Hydroxybutyrate-Hydroxyvalerate) Polymers as Degradable Biomatertals.

1995 ◽  
Vol 394 ◽  
Author(s):  
Cyril Chaput ◽  
L'Hocine Yahia ◽  
Amine Selmani ◽  
Charles-Hilaire Rivard
Keyword(s):  
Copolymer Composition ◽  
Inflammatory Reactions ◽  
Accelerated Degradation ◽  
Physico Chemical ◽  
Degradation Rates ◽  
Degradable Biomaterials ◽  
Tissue Reactions ◽  
Toxic Responses

AbstractPoly(ß-hydroxybutyrate-co-13-hydroxyvalerate) have been recently proposed as degradable biomaterials for drug delivery systems, sutures, bone plates and short-term implants. Three P-B\HV (7, 14 & 22 % HV) films were analyzed for in vitro cytotoxicity and aqueous accelerated degradation, in vivo degradation and tissue reactions. The PHB/HV materials and extracts elicit few or mild toxic responses, do not lead in vivo to tissue necrosis or abscess formation, but provoke acute inflammatory reactions slightly decreasing with the time. The degradation of PHB/HV polymers present low rates in vitro as well as in vivo. The weight loss rate generally increases with the copolymer composition (HV content) and ranges from 0.15- 0.30 (in vitro) to 0.25 %/day (in vivo). Compositional and physico-chemical changes in PHB/HV materials were rapidly detected during the accelerated hydrolysis, but were much slower to appear in vivo. The structural and mechanical integrity of PHB/HV materials tend to disappear early in vitro as well as in vivo. After 90 wks in dorsal muscular tissues of adult sheep, there was no significant dissolution of the PHB/HV polymer, 50–60% of the initial weight still remaining. PHB/HV polymers are biodegradable materials, either by hydrolysis or implantation, but with extremely low dissolution or degradation rates.

scholarly journals Biodistribution of Nanostructured Lipid Carriers in Mice Atherosclerotic Model

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3499 ◽  
Author(s):  
Devel ◽  
Almer ◽  
Cabella ◽  
Beau ◽  
Bernes ◽  
...  
Keyword(s):  
Colloidal Stability ◽  
Ex Vivo ◽  
Particle Diameter ◽  
Nanostructured Lipid Carriers ◽  
Atherosclerotic Plaques ◽  
Particle Uptake ◽  
Atherosclerotic Lesions ◽  
Physico Chemical

Atherosclerosis is a major cardiovascular disease worldwide, that could benefit from innovative nanomedicine imaging tools and treatments. In this perspective, we here studied, by fluorescence imaging in ApoE-/- mice, the biodistribution of non-functionalized and RXP470.1-targeted nanostructured lipid carriers (NLC) loaded with DiD dye. RXP470.1 specifically binds to MMP12, a metalloprotease that is over-expressed by macrophages residing in atherosclerotic plaques. Physico-chemical characterizations showed that RXP-NLC (about 105 RXP470.1 moieties/particle) displayed similar features as non-functionalized NLC in terms of particle diameter (about 60-65 nm), surface charge (about −5 — −10 mV), and colloidal stability. In vitro inhibition assays demonstrated that RXP-NLC conserved a selectivity and affinity profile, which favored MMP-12. In vivo data indicated that NLC and RXP-NLC presented prolonged blood circulation and accumulation in atherosclerotic lesions in a few hours. Twenty-four hours after injection, particle uptake in atherosclerotic plaques of the brachiocephalic artery was similar for both nanoparticles, as assessed by ex vivo imaging. This suggests that the RXP470.1 coating did not significantly induce an active targeting of the nanoparticles within the plaques. Overall, NLCs appeared to be very promising nanovectors to efficiently and specifically deliver imaging agents or drugs in atherosclerotic lesions, opening avenues for new nanomedicine strategies for cardiovascular diseases.

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