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At least 775 records · Page 43Linked to original sources
PubMed1977

[Membrane action of ionic surfactants on yeast cells].

Effect of a number of homologous series of cationic and anionic surfactants on yeast cells was examined. It is found that the cellular proteins extraction degree under the surfactants treatment depends on the agents structure. It is established that the highest extraction efficiency among the bisquaternary ammonium compounds is displayed by the decyl derivatives and among sodium alkyl sulfates--by octyl sulfate. The influence of pH, ionic strength and the agent concentration on the proteins extraction degree was studied. It is concluded that the anionic and cationic compounds act on the yeast plasma membrane by the similar way and all the differences observed are just the quantitative ones. It is suggested that the efficiency of the surfactant action on the cell is limited particularly by the ratio of cell wall pore size to the size of micelles formed by the agent in the solution.

Cell Membrane↗
PubMed1985

[Reduction of the transfer of surface active agent residues in food].

Surfactants used for cleaning and disinfection in food production and food processing can form residue on treated materials. Upon sequential contact of these materials with foods these foods may become contaminated. Different materials (steel, acrylonitrile rubber, polypropylene, polyamide, methyl methacrylate) were treated with aqueous solutions of dodecyl-trimethyl-ammoniumchloride, a bactericidal quaternary ammonium compound, and stearyl alcohol oxethylate, a nonionic surfactant. The adhering amounts of surfactants were measured by a radio tracer technique. It was analysed, how much of the adhering surfactants could be removed with water depending on rinsing time, water temperature, flow velocity, and number of rinsing cycles. It has furthermore been determined to what extent adhering surfactants are rinsed off by milk and juice.

Animals↗
PubMed2002

Rapid determination of sanitizer concentration using impedance-based methods.

Chlorine, iodophor, and quaternary ammonium solutions of various concentrations were assayed with rapid test kits and with three Bactometer impedimetric test codes (the impedance, conductance, and capacitance test codes). An initial study was conducted to determine which test code was most suitable for each sanitizer. Impedance was shown to be the best for sodium hypochlorite solutions, conductance for iodophor solutions, and capacitance for quaternary ammonium solutions. When Bactometer results were compared with test kit results, linear regression revealed strong correlations for all three sanitizer solutions. For sodium hypochlorite concentrations of 0 to 100 ppm and 100 to 1,000 ppm, R2 values of 0.87 and 0.99, respectively, were obtained. For iodophor concentrations between 25 to 150 ppm, an R2 value of 0.95 was obtained. For quaternary ammonium compound concentrations of 100 to 1,000 ppm, an R2 value of 0.94 was obtained. The impedimetric methods proved to be simple and rapid (6 min) alternatives for measuring concentrations of the sanitizer solutions with a high level of certainty (P < 0.0002). The Bactometer will save time when multiple samples are tested.

Bacteria↗
PubMedDate not supplied

[The hypolipidemic and antiatherosclerotic properties of the ammonium salt of glycyrrhetic acid and of 18-dehydroglycyrrhetic acid].

Plant compounds ammonium salt of glycyrretic acid (AGA) and 18-dehydroglycyrretic acid (18-DHGA) effectively reduced the concentration of total cholesterol, triglycerides, and atherogenic lipoproteins in blood serum of rabbits with modeled cholesterol atherosclerosis. They reduced significantly the content of malonic dialdehyde and raised the activity of superoxide dismutase in the animals' organs. Due to their powerful hypolipidemic and antioxidant effect AGA and 18-DHGA significantly reduced the surface of the atherosclerotic changes of the aorta. Both compounds considerably excel polisponin in the indicated properties.

Animals↗
PubMed2003

The toxicity of cationic surfactants in four bioassays.

The purpose of this study was to investigate the toxicity of 15 quaternary ammonium compounds (QACs) in a battery of four bioassays comprising the bacterium Vibrio fischeri, two ciliated protozoa Spirostomum ambiguum and Tetrahymena thermophia, and the anostracean crustacean Artemia franciscana. The compounds were prepared by Professor Pernak's group at Poznań University of Technology (Poland). The toxicity of the test compounds was very high, with EC(LC)(50) values varying from 0.11 to 70 micromol/L. Microtox was the most sensitive bioassay, while the crustacean test was the least sensitive. Among the protozoa T. thermophila was 5-30 times less sensitive than S. ambiguum. The toxicity of the QACs depended on their structure, but no simple correlation was found for all the bioassays applied.

Animals↗
PubMed1980

Induced activation in the deacylation step of tryptic hydrolysis. An application of "inverse substrates" to mechanistic studies of the enzyme.

Trypsin [EC 3.4.21.4]-catalyzed hydrolysis of "inverse substrates" was investigated kinetically. "Inverse substrates" for trypsin are specific substrates in which the arrangement of the site-specific group is reversed compared to that of the normal substrate, e.g., a cationic center is included in the leaving group instead of being in the acyl moiety (Tanizawa, K., Kasaba, Y., & Kanaoka, Y. (1977) J. Am. Chem. Soc. 99, 4485-4488). Acyl enzyme intermediates formed specifically from these substrates are advantageous for the mechanistic analysis of trypsin action, since the cationic group liberated from the acyl moiety can no longer exhibit specific interaction with the enzyme binding site in the subsequent deacylation stage. Remarkable rate acceleration at the deacylation step was observed on adding amidinium or ammonium compounds. The effects of the size of the acyl moiety and the charged molecule on the acceleration were examined. Latent properties of 1-butylamine as an activator were found in the present study. Based on these observations, it is suggested that a cationic molecule which can be well accommodated together with the acyl group within the active center cleft causes rate enhancement, with associated conformational changes.

Acylation↗
PubMed1976

The antiarrhythmic and cardiovascular properties of 1-dimethyl isopropylamino-3-(2-phenylphenoxy)-propan-2-ol chloride, UM-424.

The quarternary ammonium compound, UM-424 [1-dimethyl isopropylamino-3-(2-phenylphenoxy)-propan-2-ol chloride], was evaluated for its antiarrhythmic and hemodynamic effects. UM-424 converted ouabain-induced ventricular tachycardia in the anesthetized dog when administered in an average dose of 4.6 mg/kg i.v. Pretreatment of anesthetized dogs with UM-424, 10 mg/kg, provided complete protection against the development of premature beats and ventricular fibrillation when the left anterior descending coronary artery was occluded for 20 minutes and then released. UM-424 was effective in reversing ventricular arrhythmias in conscious animals which had been subjected to a two-stage ligation of the anterior descending coronary artery. The mean ectopic rate in a group of five dogs was 143 +/- 4.0 (S.E.M.) beats/min 24 hours after coronary ligation. Normal sinus rhythm was restored with a mean dose of 9.5 mg/kg of UM-424 and was maintained for a period in excess of 60 minutes. The ventricular fibrillation threshold was increased from a control value of 4.0 +/- 0.4 to 26.2 +/- 8.6 mA (P less than .05) 30 minutes after pretreatment with UM-424, 10 mg/kg. Inotropic and chronotropic dose-response studies to isoproterenol in the anesthetized dog demonstrated that the quarternary compound lacked beta adrenergic receptor blocking properties. UM-424, 10 mg/kg, did not produce any persistent changes in spontaneous heart rate, cardiac contractile force, left ventricular dP/ct, mean arterial blood pressure, cardiac output and mean pulmonary arterial pressure.

Adrenergic beta-Antagonists↗
PubMed2006

Resistance of Listeria monocytogenes biofilms to sanitizing agents in a simulated food processing environment.

The objective of this study was to evaluate the resistance of biofilms of Listeria monocytogenes to sanitizing agents under laboratory conditions simulating a food processing environment. Biofilms were initially formed on stainless steel and Teflon coupons using a five-strain mixture of L. monocytogenes. The coupons were then subjected to repeated 24-h daily cycles. Each cycle consisted of three sequential steps: (i) a brief (60 s) exposure of the coupons to a sanitizing agent (a mixture of peroxides) or saline as a control treatment, (ii) storage of the coupons in sterile plastic tubes without any nutrients or water for 15 h, (iii) and incubation of the coupons in diluted growth medium for 8 h. This regimen was repeated daily for up to 3 weeks and was designed to represent stresses encountered by bacteria in a food processing environment. The bacteria on the coupons were reduced in number during the first week of the simulated food processing (SFP) regimen, but then adapted to the stressful conditions and increased in number. Biofilms repeatedly exposed the peroxide sanitizer in the SFP regimen developed resistance to the peroxide sanitizer as well as other sanitizers (quaternary ammonium compounds and chlorine). Interestingly, cells that were removed from the biofilms on peroxide-treated and control coupons were not significantly different in their resistance to sanitizing agents. These data suggest that the resistance of the treated biofilms to sanitizing agents may be due to attributes of extracellular polymeric substances and is not an intrinsic attribute of the cells in the biofilm.

Bacterial Adhesion↗
PubMed1982

Block of outward current in cardiac Purkinje fibers by injection of quaternary ammonium ions.

We have studied the effects of iontophoretic injection of the quaternary ammonium compounds tetraethylammonium (TEA) and tetrabutylammonium (TBA) in cardiac purkinje fibers. We find that TBA(+) is a more effective blocker than TEA(+), but injection of either compound reduces the time-dependent outward plateau currents, transient outward current (I(to)), and the delayed rectifier (I(x)). Our findings provide evidence that these outward cardiac currents are carried by channels that in some respects are pharmacologically similar to squid axon potassium channels. We demonstrate that this procedure is a new tool that can be useful in the analysis of membrane currents in the heart.

Animals↗
PubMed1997

Susceptibility of antibiotic-susceptible and antibiotic-resistant hospital bacteria to disinfectants.

OBJECTIVE: To evaluate whether hospital strains of antibiotic-resistant bacteria exhibited altered susceptibility to disinfectants. DESIGN: Antibiotic-susceptible bacteria were obtained from American Type Culture Collection: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Salmonella choleraesuis, and Pseudomonas aeruginosa. Hospital strains of antibiotic-resistant bacteria were obtained from clinical isolates, including: S aureus, S epidermidis, E coli, Enterococcus species, K pneumoniae, and P aeruginosa. The Association of Official Analytical Chemist's use-dilution method was used to test these 12 strains of 7 bacterial pathogens for their susceptibility to a phenol and a quaternary ammonium compound. For five pathogens, we tested a susceptible and a more resistant strain in 20 comparative trials (5 pathogens, 2 disinfectants, 2 dilutions per disinfectant). RESULTS: In our 20 comparative trials, the antibiotic-resistant strains exhibited an increased resistance to the disinfectant in only a single instance. CONCLUSIONS: Our data demonstrate that the development of antibiotic resistance does not appear to be correlated to increased resistance to disinfectants.

Bacteria↗
PubMed1998

[Materials for carrying out external quality control in the determination of total protein].

Quaternary bis-ammonium compound No. 82 (QAC-82) is a highly effective antibacterial biochemical stabilizer of total protein. In concentrations of 3.4-13.6 mmol/liter, it preserves the content of protein in the blood serum for 40 days at 18-20 degrees C. For preparing reference material, 5 ml human or animal serum is added to 95 ml 5.25 mM aqueous solution of QAC-82, mixed, stored at room temperature, and used for assessing the quality of total protein measurements by the biuret method.

Biuret Reaction↗
PubMed1976

Electron-capture GC determination of subnanogram amounts of emepronium bromide in serum.

Barium peroxide in an acidic medium was utilized to increase the sensitivity in the benzophenone method for the determination of the quaternary ammonium compound emepronium bromide. The method is comprised of ion-pair extraction, oxidation, and quantitative determination of benzophenone by electron-capture GC. By employing small extraction and reaction volumes, the method was used in the 0.2--8-ng/ml range with a relative standard deviation of 2.5% at the 1-ng/ml level. The application of the method to human serum samples after a single oral dose demonstrated that the elimination phase for emepronium in serum had a half-life of 7--11 hr.

Administration, Oral↗
PubMed2003

Soft antibacterial agents.

Hard drugs have been defined as drugs that are biologically active and non-metabolizable in vivo. Soft drugs are defined as drugs, which are characterized by predictable and controllable in vivo destruction (i.e. metabolism) to form non-toxic products after they have achieved their therapeutic role. Quaternary ammonium compounds, such as benzalkonium chloride, are hard antibacterial agents. Their toxicity limits their usage in humans and animals, and their chemical stability limits their usage for general environmental sanitation. Furthermore, due to their stability they are prone to induce selective antimicrobial pressure and bacterial resistance. Soft analogs of the currently available hard antibacterial agents are less toxic. However, although the soft analogs have been shown to possess antibacterial activity in in vitro studies, it is likely that their in vivo activity will be hampered by their chemical instability.

Anti-Bacterial Agents↗
PubMed1985

Cloning and expression of Staphylococcus aureus plasmid-mediated quaternary ammonium resistance in Escherichia coli.

The Staphylococcus aureus plasmid pSK1 carries Tn4001, a 4.7-kilobase (kb) transposon which specifies resistance to gentamicin, tobramycin, and kanamycin. In addition, pSK1 mediates resistance to trimethoprim and linked resistance to ethidium bromide (Ebr) and to quaternary ammonium compounds (Qar). Restriction endonuclease analysis of pSK1 and a deleted derivative of pSK1 revealed that the gene(s) responsible for Ebr Qar lies within a 5.2-kb HindIII fragment. This fragment has been cloned into the Escherichia coli plasmid vector pBR322, and transformants of an E. coli K-12 strain exhibited Ebr Qar. Subcloning of the 5.2-kb insert, combined with data from electron microscopic analysis of deleted derivatives of pSK1, located the Ebr Qar determinant(s) on a 2.3-kb segment of pSK1 DNA.

Chromosome Mapping↗
PubMed1977

The effect of ion pair formation on the antimuscarinic activity of methantheline.

The quaternary ammonium compound, methantheline, was found to antagonize acetylcholine induced contractions in isolated guinea pig ileum by a mechanism which did not conform to the criteria for either competitive or non-competitive inhibition. Enhancement of the lipid solubility of methantheline by formation of an ion pair with trichloracetate failed to influence its cholinergic inhibitory activity. The results suggest that in the guinea pig ileum a) an intracellular site of action does not exist for methantheline and b) the membrane receptors for methantheline most likely are located in an aqueous environment.

Acetylcholine↗
PubMed2002

The sedimentation capabilities of hexadecyltrimethylammonium-modified montmorillonites.

Natural montmorillonite was modified with a quaternary ammonium compound, hexadecyltrimethylammonium (HDTMA). The sedimentation capabilities of unmodified and modified montmorillonites were then investigated. The sedimentation velocity of modified montmorillonites increased if the amounts of adsorbed HDTMA were from 0.3 to 1.0 times the cation exchange capacitity (CEC). It also emerged that the sedimentation capability of modified montmorillonites was improved and that the variously CEC-modified montmorillonites had similar sedimentation capabilities after they had sorbed organic matter from oily wastewater. Thus, modified montmorillonites (especially 0.5 CEC treatment) had good sedimentation capabilities for sorbing organic substance and can act as carriers in wastewater biotreatment.

Adsorption↗
PubMed1983

Disinfection of gastrointestinal fibrescopes--evaluation of the disinfectants Dettox and Gigasept.

The disinfectant solutions Dettox (based on a quaternary ammonium compound) and Gigasept (based on succine dialdehyde) were evaluated during disinfection procedures with a new disinfecting apparatus for gastrointestinal fibrescopes. Thorough disinfection was achieved after 2 minutes using Dettox 8% or Gigasept 10%; persistent fibrescope contamination with Gram-negative organisms was found after disinfection with Dettox 4% or Gigasep 5%. No adverse effects in endoscopy staff or damage to fibrescopes were seen. Adequate disinfection of endoscopic equipment prevents endoscopy-related infection and can be readily achieved by trained endoscopy staff using rapidly bactericidal disinfectants.

Aldehydes↗
PubMed1995

[Disinfection of wood in mushroom growing cellars with Mycetox].

Since the use od phenolic disinfectants for impregnating and disinfecting of wood in mushroom--growing cellars was banned in Poland for ecologic and hygienic reasons, the new product, namely Mycetox, containing quaternary ammonium compound and boric acid has been registered for this purpose. Mycetox belongs to new generation products and is non toxic for man and the environment. It is first Polish product developed for the general disinfection as well as for impregnating purposes in mushroom farms. The efficacy of Mycetox in mushroom-growing cellars has been evaluated basing on its fungicidal properties in the different substrates used for the cultivation of mushrooms. Also its influence on mushroom spawn growth, crop yield, and the penetration of spawn into wooden cages impregnated with Mycetox as well as its influence on blanching of mushrooms has been investigated.

Agaricus↗