This article reviews the recent studies on H2O2 adaptation of Saccharomyces cerevisiae. When the cell exposed in the H2O2 sub-lethal doses, the plasma membrane permeability decreased, meanwhile the plasma membrane fluidity is minished. These changes resulted in a gradient across the plasma membrane, which conferring a higher resistance to oxidative stress. Recent work has also shown that the yeast cells adapted to H2O2 would lead to several changes in the expression of genes coding the key enzymes involved in the biosynthesis of lipid profile and in the organization of lipid microdomains of the plasma membrane, which finally decreased its' permeability and fluidity. The reorganization of the plasma membrane might be the major mechanism of the H2O2 adaptation. Once the yeast cells adapted to the external H2O2, changes in plasma occurred. The H2O2 dependent signaling pathways in the plasma membrane might be activated by high levels of H2O2. But the details of the signaling events should still be further studies.
Cell Membrane ; drug effects ; metabolism ; Cell Membrane Permeability ; drug effects ; Hydrogen Peroxide ; pharmacology ; Membrane Fluidity ; drug effects ; Saccharomyces cerevisiae ; cytology ; drug effects ; Signal Transduction ; drug effects

OBJECTIVETo study the effects of domoic acid (DA) on membrane function of primary cultured rat glial cell.

METHODSAfter the glial cells were treated with 6.4 x 10(-2), 6.4 x 10(-3) and 6.4 x 10(-4) micromol/L DA for 24 h, the activities of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase, the membrane fluidity and the permeability were measured to reflect the membrane function.

RESULTSAfter treatment of DA for 24 h, the activities of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase were inhibited significantly, the membrane fluidity decreased and the membrane permeability increased. The fluorescence polarization and microviscosity in the low, middle and high dosage treatment groups were 0.0626 +/- 0.0051, 0.0685 +/- 0.0097, 0.0648 +/- 0.0086 and 0.3154 +/- 0.0298, 0.3510 +/- 0.0571, 0.3286 +/- 0.0504 respectively, compared with the control group (0.0481 +/- 0.0069 and 0.2338 +/- 0.0372) (P < 0.01).

CONCLUSIONDA has obvious effects on membrane function of rat glial cells and may cause further injury on the cells.

Animals ; Cell Membrane ; drug effects ; Cell Membrane Permeability ; drug effects ; Cells, Cultured ; Kainic Acid ; analogs & derivatives ; pharmacology ; Membrane Fluidity ; drug effects ; Neuroglia ; drug effects ; Rats ; Rats, Sprague-Dawley

The microstructure of cationic cyclopeptide (TD-34) treated Caco-2 cell membrane was observed, and we discussed the relationship between membrane structure and insulin transmembrane permeability. Atomic force microscope (AFM) was used to observe living cell membrane in air condition and tapping mode. Results showed that the surface of Caco-2 cell membrane treated with TD-34 lost its smoothness and nearly doubled its roughness. Apparent permeability coefficients (P(app)) of insulin in Caco-2 cell monolayers increased 2.5 times. In conclusion, AFM can be used to observe microstructure of cationic cyclopeptide treated cell membrane and cationic cyclopeptide enhanced insulin delivery across Caco-2 cell membrane by increasing membrane fluidity.
Caco-2 Cells ; Cations ; Cell Membrane ; drug effects ; Cell Membrane Permeability ; drug effects ; Humans ; Insulin ; metabolism ; Membrane Fluidity ; drug effects ; Microscopy, Atomic Force ; Peptides, Cyclic ; pharmacology

Ca2+ at 1.64 mmol/L markedly increased ethanol tolerance of a self-flocculating fusant of Schizosaccharomyces pombe and Saccharomyces cerevisiae. After 9 h of exposure to 20% (V/V) ethanol at 30 degrees C , no viability remained for the control whereas 50.0% remained for the cells both grown and incubated with ethanol in Ca2+ -added medium. Furthermore, when subjected to 15% (V/V) ethanol at 30 degrees C, the equilibrium nucleotide concentration and plasma membrane permeability coefficient (P' ) of the cells both grown and incubated with ethanol in Ca2+ -added medium accounted for only 50.0% and 29.3% those of the control respectively, indicating that adding Ca2+ can markedly reduce plasma membrane permeability of yeast cells under ethanol stress as compared with the control. Meanwhile, high viability levels acquired by the addition of Ca2+ exactly corresponded to the striking decreases in extracellular nucleotide concentration and P' achieved with identical approach. Therefore, the enhancing effect of Ca2+ on ethanol tolerance of this strain is closely related to its ability to decrease plasma membrane permeability of yeast cells subjected to ethanol stress.
Calcium ; pharmacology ; Cell Membrane ; drug effects ; metabolism ; Cell Membrane Permeability ; drug effects ; Ethanol ; pharmacology ; Saccharomyces cerevisiae ; drug effects ; growth & development ; metabolism ; Schizosaccharomyces ; drug effects ; growth & development ; metabolism ; Temperature

OBJECTIVETo investigate the effect of c-Met inhibitor cabozantinib (XL-184) in inhibiting Listeria monocytogenes (LM) from invading Caco-2 cells to reduce the cell injury.

METHODSThe cell invasion capacity of LM was assayed in Caco-2 cells incubated with different doses of XL-184 for different durations. Caco-2 cells incubated with XL-184 were seeded on the upper room of the transwell chamber, and the cell monolayer was exposed to LM infection followed by addition of horseradish peroxidase (HRP). The trans-epithelial electric resistance (TEER), HRP concentration and LM colony-forming unit (CFU) were measured in the cell monolayer. Fluorescent staining was used to evaluate the cell viability, and LDH release from the cells was examined to assess the changes in cell membrane permeability.

RESULTSXL-184 significantly decreased LM invasion rate in Caco-2 cells in a dose- and time-dependent manner (P=0.000), and this effect was enhanced by co-incubation of the cells with ampicillin (P<0.05). In the cell membrane permeability assay in the monolayer cells, XL-184 markedly inhibited LM-induced reduction of TEER (P<0.05) and significantly suppressed LM-induced enhancement of cell membrane permeability shown by reduced HRP concentration and LM count in the lower chamber (P=0.000). The cells infected with LM showed significantly lowered cell viability, which was rescued by XL-184 (P<0.01); XL-184 also dose-dependently reduced LDH release from the cells (P<0.05).

CONCLUSIONSXL-184 can suppress LM invasion in Caco-2 cells to reduce the cell injury, suggesting its value as a promising candidate agent for prevention and treatment of LM infections.

Anilides ; pharmacology ; Caco-2 Cells ; Cell Membrane Permeability ; drug effects ; Cell Survival ; Humans ; Listeria monocytogenes ; drug effects ; Pyridines ; pharmacology

Due to their lower risk for induction of resistance, membrane-active antimicrobial peptides with anticancer effect are attractive in cancer therapy. Because cell binding contributes to the cytotoxicity of peptide, it is possible to enhance the cytotoxicity of antimicrobial peptide in tumor cells by conjugation to a cell-penetrating peptide (CPP). In this paper, a fusion peptide MPGA by conjugation of antimicrobial peptide MP to CPP Antp at its N-terminus was constructed. After compared the cytotoxicity of unconjugated MP with that of the fusion peptide, it was found that MPGA showed higher cytotoxicity than that of unconjugated MP. And the fusion peptide MPGA induced cell death in tumor cells by membrane disruption. These results demonstrated that the cytotoxicity of antimicrobial peptide can be significantly enhanced by conjugation to CPP, which might be an effective way to develop novel anticancer drugs.
Antimicrobial Cationic Peptides ; pharmacokinetics ; pharmacology ; Antineoplastic Agents ; pharmacokinetics ; pharmacology ; Cell Line, Tumor ; Cell Membrane Permeability ; drug effects ; Humans

OBJECTIVETo investigate the increased podocyte permeability by evidence of adriamycin (AD) and its molecular mechanism.

METHODSIn this study, we explored the direct effects of AD on cultured mouse podocytes and the potential protection effects of Dexamethasome (Dex).

RESULTSAfter 24-hour AD (5 x 10(-7) mol/L) treatment, albumin passage through podocyte monolayers was increased by 2.27-fold (P < 0.01). AD caused a 62% decrease in Zonula Occluden-1 (ZO-1) protein (P < 0.05), suggesting that AD might increase podocyte permeability by disrupting tight junctions. Dex (1 x 10(-6) mol/L), co-administered with AD, protected podocytes from AD-induced increased albumin passage. This may be linked with an increased P-cadherin protein level to 1.93 fold of control (P < 0.01).

CONCLUSIONSAD has a direct, detrimental effect on podocyte permeability, probably through disrupting tight junctions; Dex could protect against AD-induced high podocyte permeability by upregulating adherent protein P-cadherin.

Albumins ; metabolism ; Animals ; Cadherins ; analysis ; Cell Membrane Permeability ; drug effects ; Cells, Cultured ; Dexamethasone ; pharmacology ; Doxorubicin ; pharmacology ; Epithelial Cells ; drug effects ; Kidney Glomerulus ; cytology ; drug effects ; Mice

Local anesthetics at a concentration of 10 mM(procaine and lidocaine) were found to inhibit competitively Ca++ binding to lipidextracted RBC membrane, and also to egg albumin film fixed on cover glasses or impregnated into Whatman filter paper (No. 1). A competitive inhibition by local anesthetics was also found in Ca++ binding to Whatman filter paper which had been pretreated with organic solvents to extract possible contaminated lipids. Therefore, it is suggested that the local anesthetics inhibit Ca++ binding not only to phospholipids but to some macromolecules such as membrane proteins, egg albumin film and filter paper.
Anesthetics, Local/pharmacology* ; Calcium/metabolism* ; Cell Membrane Permeability/drug effects ; Erythrocytes/cytology* ; Filtration ; Human ; Lidocaine/pharmacology ; Ovalbumin/metabolism* ; Procaine/pharmacology

In this study, we analyzed the kinetics of bioconversion of conjugated linoleic acid (CLA) by permeabilized Lactobacillus acidophilus cells. The effects of cell mass, linoleic acid (LA) concentration, reaction pH and temperature on the bioconversion of CLA by permeabilized cells were investigated and the model system of bioconversion of CLA was established. The results showed that the production of CLA was increased by permeabilized cells. The optimal cell mass, pH and temperature of bioconversion of CLA were 10 x 10(10) ufc/mL, 4.5 and 45 degrees C, respectively. A marked LA inhibition phenomenon existed, and the early reaction rate of producing CLA reached the maximum (17.8 microg/mL x min) when LA concentration was 0.6 mg/mL. Michaelis constant was obtained by double-reciprocal plot and Hanes-Woolf plot. The reaction rate equation followed the classic Michaelis-Mentent equation at the low LA concentration, while there was a marked LA inhibition phenomenon at the high LA concentration. With the evaluated model parameters, the model system appeared to provide a description for the bioconversion of CLA by permeabilized Lactobacillus acidophilus cells.
Biotransformation ; Cell Membrane Permeability ; drug effects ; Kinetics ; Lactobacillus acidophilus ; metabolism ; Linoleic Acid ; chemistry ; metabolism ; Linoleic Acids, Conjugated ; chemistry ; metabolism

OBJECTIVETo develop and investigate GLL-37, a substitution analogue of the human antimicrobial peptide LL-37 with anti-enzymatic degradation activity and improved efficacy.

METHODSThe bactericidal activities of LL-37 and newly developed GLL-37 against 6 Gram-negative and -positive bacteria were determined by Broth microdilution assays. The minimum inhibitory concentrations of LL-37 and GLL-37 against E.coli ATCC 25922 in different NaCl concentration medium were also detected. Both peptides were co-incubated with elastase, and then analyzed by PAGE electrophoresis and bactericidal activity determination.

RESULTGLL-37 showed a stronger elastase resistance ability than LL-37, and was significantly more effective than LL-37 under high-salt condition.

CONCLUSIONThe antimicrobial peptide GLL-37 derived form LL-37 has the potential as a new therapeutic agent for bacterial infections.

Animals ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Antimicrobial Cationic Peptides ; pharmacology ; therapeutic use ; Blood Bactericidal Activity ; drug effects ; Cathelicidins ; Cell Membrane Permeability ; drug effects ; Escherichia coli ; drug effects ; Female ; Humans ; Membrane Proteins ; metabolism ; Monocytes ; drug effects ; Pseudomonas Infections ; drug therapy