Extensions of Counterion Condensation Theory. 2. Cell Model and Osmotic Pressure of DNA

2003 ◽  
Vol 107 (18) ◽  
pp. 4451-4458 ◽  
Author(s):  
J. Michael Schurr ◽  
Bryant S. Fujimoto
Keyword(s):  
Osmotic Pressure ◽  
Cell Model ◽  
Counterion Condensation

scholarly journals Osmotic pressure in polyelectrolyte solutions: cell-model and bulk simulations

Soft Matter ◽  
2018 ◽  
Vol 14 (28) ◽  
pp. 5832-5846 ◽  
Author(s):  
Magnus Ullner ◽  
Khawla Qamhieh ◽  
Bernard Cabane
Keyword(s):  
Boundary Conditions ◽  
Osmotic Pressure ◽  
Periodic Boundary ◽  
Cell Model ◽  
Periodic Boundary Conditions ◽  
Spherical Cell ◽  
Polyelectrolyte Solutions

The osmotic pressure of polyelectrolyte solutions as a function of concentration has been calculated by simulations of a spherical cell model and by simulations with periodic boundary conditions.

Endogenous hydrogen sulfide sulfhydrates IKKβ at cysteine 179 to control pulmonary artery endothelial cell inflammation

2019 ◽  
Vol 133 (20) ◽  
pp. 2045-2059 ◽  
Author(s):  
Da Zhang ◽  
Xiuli Wang ◽  
Siyao Chen ◽  
Selena Chen ◽  
Wen Yu ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Endothelial Cell ◽  
Pulmonary Artery ◽  
Cell Model ◽  
Site Directed Mutagenesis ◽  
Critical Event ◽  
Hypertensive Rats ◽  
Pulmonary Artery Endothelial Cell

Abstract Background: Pulmonary artery endothelial cell (PAEC) inflammation is a critical event in the development of pulmonary arterial hypertension (PAH). However, the pathogenesis of PAEC inflammation remains unclear. Methods: Purified recombinant human inhibitor of κB kinase subunit β (IKKβ) protein, human PAECs and monocrotaline-induced pulmonary hypertensive rats were employed in the study. Site-directed mutagenesis, gene knockdown or overexpression were conducted to manipulate the expression or activity of a target protein. Results: We showed that hydrogen sulfide (H2S) inhibited IKKβ activation in the cell model of human PAEC inflammation induced by monocrotaline pyrrole-stimulation or knockdown of cystathionine γ-lyase (CSE), an H2S generating enzyme. Mechanistically, H2S was proved to inhibit IKKβ activity directly via sulfhydrating IKKβ at cysteinyl residue 179 (C179) in purified recombinant IKKβ protein in vitro, whereas thiol reductant dithiothreitol (DTT) reversed H2S-induced IKKβ inactivation. Furthermore, to demonstrate the significance of IKKβ sulfhydration by H2S in the development of PAEC inflammation, we mutated C179 to serine (C179S) in IKKβ. In purified IKKβ protein, C179S mutation of IKKβ abolished H2S-induced IKKβ sulfhydration and the subsequent IKKβ inactivation. In human PAECs, C179S mutation of IKKβ blocked H2S-inhibited IKKβ activation and PAEC inflammatory response. In pulmonary hypertensive rats, C179S mutation of IKKβ abolished the inhibitory effect of H2S on IKKβ activation and pulmonary vascular inflammation and remodeling. Conclusion: Collectively, our in vivo and in vitro findings demonstrated, for the first time, that endogenous H2S directly inactivated IKKβ via sulfhydrating IKKβ at Cys179 to inhibit nuclear factor-κB (NF-κB) pathway activation and thereby control PAEC inflammation in PAH.

Search for Compounds Suppressing Intestinal α-Glucosidase Expression in Caco-2 Cells

2019 ◽  
Vol 2 (2) ◽  
pp. 96-101
Author(s):  
Kota Noda ◽  
Eisuke Kato ◽  
Jun Kawabata
Keyword(s):  
Blood Glucose ◽  
Intestinal Tract ◽  
Cell Model ◽  
Epigallocatechin Gallate ◽  
Calluna Vulgaris ◽  
Active Principle ◽  
Intestinal Epithelial ◽  
Mrna Expression Level ◽  
Epicatechin Gallate ◽  
Control Post

Diabetes is a chronic disease characterized by elevated blood glucose level.Reducing carbohydrate absorption from the intestinal tract is an effective strategy to control post-meal blood glucose level. Inhibition of intestinal α-glucosidase, involved in digestion of carbohydrates, is known as an approach to accomplish this. On the other hand, reduction of α-glucosidase amount is expected to work in the similar manner. However, none of the previousstudy pursues this approach. A convenient assay was developed to evaluate α-glucosidase amount employing Caco-2 cells, the intestinal epithelial cell model reported to express α-glucosidase. Sixty plants were screened and two candidate plants, Calluna vulgaris and Perilla frutescens var. crispa were found to reduce α-glucosidase expression. C. vulgaris extract was subjected to activity guided isolation. Proanthocyanidin was identified as the active principle which was analyzed by thiol decomposition to reveal the components as a mixture ofcatechin, epicatechin, epigallocatechin, and A type procyanidin dimer. The proanthocyanidin suppressed about 30% of α-glucosidase amount evaluated through convenient assay, and suppressed bulk of mRNA expression level of sucrase-isomaltase (SI) at 0.125 mg/mL. Several flavan-3-ol monomers were also tested, and epicatechin gallate and epigallocatechin gallate were found to suppress α-glucosidase amount significantly.

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