Adenosinetriphosphate, calcium and temperature requirements for the final steps of exocytosis in Paramecium cells

1978 ◽  
Vol 32 (1) ◽  
pp. 67-86
Author(s):  
H. Matt ◽  
M. Bilinski ◽  
H. Plattner
Keyword(s):  
Membrane Fusion ◽  
Cetyltrimethylammonium Bromide ◽  
Membrane Lipids ◽  
Energy Requirement ◽  
Gradient Centrifugation ◽  
Cetylpyridinium Chloride ◽  
Cationic Detergents ◽  
Matrix Bound ◽  
Membrane Resealing ◽  
Stretching Process

In Paramecium cells a synchronized discharge of trichocysts (which involves only the final exocytosis steps of membrane fusion, content discharge and membrane resealing) was achieved with ATPase-blockers, Ca2+-ionophores, lipid solvents (including lysolecithin), polyethyleneglycol, anaesthetics (Dibucain) and cationic detergents (cetyltrimethylammonium bromide (CTMAB) and cetylpyridinium chloride (CPC). Only Dibucain—and to some extent cationic detergents—can trigger exocytosis independently of extracellular Ca2+, possibly by mobilizing intracellular Ca2+. The internal free [Ca2+] necessary for exocytosis can be estimated to be greater than 10(−6) to 10(−4) M. Membrane-free trichocyst contents were isolated by density gradient centrifugation; they are converted from the contracted to the expanded state by Dibucain, CTMAB and CPC, and also by exogenous ATPase (Apyrase). Thus, it is possible to de-couple the discharge (stretching) process from membrane-related phenomena. Since only the latter are inhibited by low temperature (0 degrees C), membrane lipids probably have to be in a fluid state for exocytosis to occur. At least 2 steps appear to be involved: when membrane fusion is initiated, an independent matrix-bound system is activated for the synchronized stretching process. The energy requirement for one discharge event is estimated to be about 14 X 10(6) ATP molecules.

scholarly journals Role of endosomal membrane lipids and NPC2 in cholesterol transfer and membrane fusion

2010 ◽  
Vol 51 (7) ◽  
pp. 1747-1760 ◽  
Author(s):  
Misbaudeen Abdul-Hammed ◽  
Bernadette Breiden ◽  
Matthew A. Adebayo ◽  
Jonathan O. Babalola ◽  
Günter Schwarzmann ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Membrane Lipids ◽  
Endosomal Membrane

Micellar catalysis of organic reactions. VIII. Kinetic studies of the hydrolysis of 2-acetyloxybenzoic acid (aspirin) in the presence of micelles

1982 ◽  
Vol 35 (7) ◽  
pp. 1357 ◽  
Author(s):  
TJ Broxton
Keyword(s):  
Aqueous Solution ◽  
Cetyltrimethylammonium Bromide ◽  
Cetylpyridinium Chloride ◽  
Kinetic Studies ◽  
Base Catalysis ◽  
Plateau Region ◽  
General Base ◽  
Mechanism Of Hydrolysis ◽  
Ph Range ◽  
Hydrolysis Of

The hydrolysis of 2-acetyloxybenzoic acid in the pH range 6-12 has been studied in the presence of micelles of cetyltrimethylammonium bromide (ctab) and cetylpyridinium chloride (cpc). In the plateau region (pH 6-8) the hydrolysis is inhibited by the presence of micelles, while in the region where the normal BAC2 hydrolysis (pH > 9) occurs the reaction is catalysed by micelles of ctab and cpc. The mechanism of hydrolysis in the plateau region is shown to involve general base catalysis by the adjacent ionized carboxy group both in the presence and absence of micelles. This reaction is inhibited in the presence of micelles because the substrate molecules are solubilized into the micelle and water is less available in this environment than in normal aqueous solution.

scholarly journals Group of peptides that act synergistically with hydrophobic antibiotics against gram-negative enteric bacteria.

1996 ◽  
Vol 40 (8) ◽  
pp. 1801-1805 ◽  
Author(s):  
M Vaara ◽  
M Porro
Keyword(s):  
Synthetic Peptide ◽  
Bacterial Species ◽  
Cetylpyridinium Chloride ◽  
Enteric Bacteria ◽  
Polymyxin B ◽  
Disulfide Bridge ◽  
Gram Negative ◽  
E Coli ◽  
Cationic Detergents ◽  
Lysine Residues

A synthetic peptide, KFFKFFKFFK [corrected], consisting of cationic lysine residues and hydrophobic phenylalanine residues was found to sensitize gram-negative bacteria to hydrophobic and amphipathic antibiotics. At a concentration of 3 micrograms/ml, it decreased the MIC of rifampin for smooth, encapsulated Escherichia coli by a factor of 300. Other susceptible bacterial species included Enterobacter cloacae, Klebsiella pneumoniae, and Salmonella typhimurium, but Pseudomonas aeruginosa was resistant. Similar results were obtained with another synthetic peptide, IKFLKFLKFLK [corrected]. The fractional inhibitory concentration indices for the synergism of these peptides with rifampin, erythromycin, fusidic acid, and novobiocin were very close to those determined for the previously characterized potent outer-membrane-disorganizing agents polymyxin B nonapeptide and deacylpolymyxin B. KFFKFFKFFK [corrected] had direct activity against the gram-positive organism Micrococcus strain ML36, was strongly hemolytic, and was as active on polymyxin-resistant E. coli mutants as on their parent. These three attributes made KFFKFFKFFK [corrected] different from polymyxin derivatives and similar to cationic detergents, such as cetylpyridinium chloride. However, whereas the MIC of cetylpyridinium chloride for E. coli is low (0.5 to 4 micrograms/ml), that of KFFKFFKFFK [corrected] is much higher (30 to 100 micrograms/ml). Other groups of synthetic peptides studied included polymyxin-like peptides with an intrachain disulfide bridge. Their synergism with antibiotics was less marked. Still other peptides, including KEKEKEKEKE and KKKKKKFLFL, lacked any synergism with the probe antibiotics.

scholarly journals Eight Gram-negative bacteria are 10 000 times more sensitive to cationic detergents than to anionic detergents

2003 ◽  
Vol 49 (12) ◽  
pp. 775-779 ◽  
Author(s):  
Soumitra Rajagopal ◽  
Nicole Eis ◽  
Kenneth W Nickerson
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Cetyltrimethylammonium Bromide ◽  
Liquid Culture ◽  
Sodium Dodecyl ◽  
Homoserine Lactone ◽  
Luria Bertani ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Cationic Detergents ◽  
Dodecyl Sulfate

In liquid culture, eight typical Gram-negative bacteria were ca. 10 000-fold more sensitive to cationic detergents than to the anionic detergent sodium dodecyl sulfate. Cetyltrimethylammonium bromide (CTAB) was inhibitory at concentrations ranging from 0.0006% to 0.01%. Four pseudomonads able to form biofilms were ca. 1000-fold more resistant to CTAB on Luria–Bertani agar plates than they were in liquid culture. A lasI mutant of Pseudomonas aerugi nosa was only able to tolerate 0.1% CTAB on Luria–Bertani agar plates but could tolerate 5% CTAB when supplemented with homoserine lactone containing culture supernatants.Key words: sodium dodecyl sulfate, cetyltrimethylammonium bromide, bacterial detergent resistance, homoserine lactones, Pseudomonas biofilms.

scholarly journals Cetylpyridinium chloride produces increased zeta-potential on Salmonella Typhimurium cells, a mechanism of the pathogen’s inactivation

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Yagmur Yegin ◽  
Jun K. Oh ◽  
Mustafa Akbulut ◽  
Thomas Taylor
Keyword(s):  
Zeta Potential ◽  
Salmonella Typhimurium ◽  
Membrane Lipids ◽  
Cetylpyridinium Chloride ◽  
Membrane Integrity ◽  
Electrostatic Repulsion ◽  
Phase Interaction ◽  
Human Pathogens ◽  
Two Phase ◽  
Oppositely Charged

Abstract Cetylpyridinium chloride (CPC) is a quaternary ammonium sanitizer approved for fresh poultry animal carcass sanitization from microbial human pathogens, such as Salmonella enterica. Nonetheless, the interactions of CPC with Salmonella cells, and the mechanism of the sanitizer’s neutralization by lecithin remains largely unknown. This study aimed to investigate the interaction of CPC with lecithin and Salmonella Typhimurium to determine the interactions of the sanitizer and neutralizer impacting the bacterium’s survival. Application of 0.8% CPC is proposed to produce loss of microbial membrane integrity with loss of electrostatic repulsion between individual cells, resulting in the eventual emulsification of membrane lipids with cytoplasmic contents leakage. Our findings point to a two-phase interaction between CPC and lecithin impacting S. Typhimurium survival. The first consists of electrostatic attraction and charge neutralization between oppositely charged components of pathogen cell and CPC. The second involves formation of aggregates between sanitizer and pathogen, or between sanitizer, pathogen membrane lipids, and lecithin.

Composition, biophysical properties, and morphometry of plasma membranes in pulmonary interstitial edema

2002 ◽  
Vol 282 (6) ◽  
pp. L1382-L1390 ◽  
Author(s):  
Paola Palestini ◽  
Chiara Calvi ◽  
Elena Conforti ◽  
Laura Botto ◽  
Carla Fenoglio ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Plasma Membranes ◽  
Cell Activation ◽  
Membrane Lipids ◽  
Gradient Centrifugation ◽  
Mechanical Stimuli ◽  
Biophysical Properties ◽  
Interstitial Edema ◽  
Vascular Perfusion

We evaluated the changes in plasma membrane composition, biophysical properties, and morphology of pulmonary endothelial cells in anesthetized rabbits receiving 0.5 ml · kg−1 · min−1 saline infusion for 180 min, causing mild interstitial edema. Plasma membrane fractions were obtained from lung homogenates with gradient centrifugation, allowing a sixfold enrichment in caveolin-1. In edematous lungs, cholesterol content and phospholipidic phosphorus increased by 15 and 40%, respectively. These data correlated with morphometric analysis of lungs fixed in situ by vascular perfusion with 2.5% glutaraldehyde, suggesting a relative increase in surface of luminal to interstitial front of the capillary endothelial cells, due to a convoluted luminal profile. In edematous lungs, the fraction of double-bound fatty acids increased in membrane lipids; moreover, the phosphatidylcholine/phosphatidylethanolamine and the cholesterol/phospholipid ratios decreased. These changes were consistent with the increase in fluorescence anisotropy of plasma membrane, indicating an increase in its fluidity. Data suggest that mechanical stimuli elicited by a modest (∼4%) increase in extravascular water cause marked changes in plasma membranes that may be of relevance in signal transduction and endothelial cell activation.

scholarly journals SugE, a New Member of the SMR Family of Transporters, Contributes to Antimicrobial Resistance inEnterobacter cloacae

2011 ◽  
Vol 55 (8) ◽  
pp. 3954-3957 ◽  
Author(s):  
Gui-Xin He ◽  
Chu Zhang ◽  
Robert R. Crow ◽  
Conner Thorpe ◽  
Huizhong Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Sodium Dodecyl Sulfate ◽  
Benzalkonium Chloride ◽  
Cetyltrimethylammonium Bromide ◽  
Cetylpyridinium Chloride ◽  
Sodium Dodecyl ◽  
Enterobacter Cloacae ◽  
Drug Efflux ◽  
Energy Dependent

ABSTRACTWe cloned a gene,sugE, from the chromosome ofEnterobacter cloacaeATCC 13047. Analysis of the susceptibilities of thesugE-containing strain (Escherichia coliKAM32/pSUGE28) andsugE-deficientE. cloacae(EcΔsugE) showed that SugE confers resistance to cetyltrimethylammonium bromide, cetylpyridinium chloride, tetraphenylphosphonium, benzalkonium chloride, ethidium bromide, and sodium dodecyl sulfate. We also investigated expression ofsugE. We confirm here that SugE fromE. cloacaeis an SMR family transporter as determined by observing its energy-dependent drug efflux activity.

The cesium-induced delay in myoblast membrane fusion is accompanied by changes in isolated membrane lipids

1990 ◽  
Vol 1023 (2) ◽  
pp. 298-304 ◽  
Author(s):  
Maria T. Santini ◽  
Pietro L. Indovina ◽  
Alfredo Cantafora ◽  
Ida Blotta
Keyword(s):  
Membrane Fusion ◽  
Membrane Lipids

Interaction of Porphyrins with Cetyltrimethylammonium Bromide Micelles in Methylene Chloride

1998 ◽  
Vol 02 (04) ◽  
pp. 345-351 ◽  
Author(s):  
NILKAMAL BAG ◽  
ARUNA DHATHATHREYAN ◽  
ASIT BARAN MANDAL ◽  
TIRUMALACHARI RAMASAMI
Keyword(s):  
Free Energy ◽  
Cetyltrimethylammonium Bromide ◽  
Methylene Chloride ◽  
Aggregation Number ◽  
Film Formation ◽  
Cetylpyridinium Chloride ◽  
Standard Free Energy ◽  
Micelle Formation ◽  
Standard Free Energy Change ◽  
Biphasic Model

The formation of micelles of cetyltrimethylammonium bromide (CTAB) in CH 2 Cl 2 solution has been reported for the first time. The critical micelle concentrations (cmc) of CTAB in CH 2 Cl 2 solution were determined using conductivity and fluorescence techniques in both the absence and presence of 1,3,5,7-tetramethyl-2,4,6,8-tetra(2,4,6-triisopropylphenyl)porphyrin (TMTIP). The cmc values obtained by conductivity and fluorescence methods were found to be 75 and 78 mM, respectively. The aggregation numbers (N) of CTAB and porphyrin–CTAB in CH 2 Cl 2 solution were determined using pyrene and N-cetylpyridinium chloride (CPC) as the fluoroprobe and quencher, respectively. The N of CTAB in CH 2 Cl 2 solution was also determined using the porphyrin (in lieu of pyrene) as the fluoroprobe and CPC as the quencher. The N of CTAB obtained by these probes was found to be 134 ± 3 and 140 ± 5, respectively. This suggests that the porphyrin could be used as an excellent fluoroprobe for determination of the aggregation number of CTAB micelles. The results of both cmc and aggregation number suggest that the micelle formation of CTAB in CH 2 Cl 2 solution is favored in the presence of the porphyrin. The standard free energy change for micelle formation of CTAB in CH 2 Cl 2 solution was calculated using a biphasic model. The standard free energy transfer [Formula: see text] of CTAB micelles from CH 2 Cl 2 to porphyrin environment has been found to be −1.0 kJ mol−1 at 25 °C, suggesting that the above transfer is difficult. However, the reverse situation, i.e. binding of the porphyrin to CTAB micelles, is more probable. The Langmuir–Blodgett (LB) film formation of the porphyrin and metalloporphyrins ( Fe , Co , Cu , Zn ) has also been studied and the UV-vis spectra of these films have been analyzed.

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