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PubMed2000

[Study on taxol release in the two-liquid-phase cultures of Taxus cuspidata].

Effects of rare earth compound (ammonium sulphate), organic solvents(oleic acid and dibutylphthalate) and the integrated function of the rare earth compound and organic solvents were studied on taxol release in the Taxus cuspidata suspension cultures. And then effects of different organic solvents(paraffin, organic acid, alcohol and ester), their volumetric fraction and phase toxicity were studied on taxol release in the two-liquid-phase cultures of Taxus cuspidata. The results showed that the addition of the rare earth compound or the organic solvents could strengthen obviously taxol release, especially the organic solvents. But the addition of the rare earth compound could not strengthen further taxol release in the twoliquid-phase cultures of Taxus cuspidata. Therefore the organic solvents were very good permeabilizing reagents, which could enhance obviously secondary metabolite in the twoliquid-phase cultures of plant cells. Release percentage of taxol was increased into more than 75% from 40% of the control.

Antineoplastic Agents, Phytogenic↗
PubMedDate not supplied

[Effect of nitrogen source on growth of Arthrobacter simplex and its biosynthesis of cholinesterase].

The effect of organic and inorganic forms of nitrogen on biomass accumulation and cholinesterase synthesis was studied with Arthrobacter simplex var. cholinesterasus. The culture assimilates nitrogen of ammonium compounds better than other forms of inorganic nitrogen; the best nitrogen source for biosynthesis of cholinesterase is ammonium phosphate. Nitrogen of nitrates is not assimilated. The amount of biomass is almost twice as high on the medium with peptone, casein or casein hydrolysate as on the medium with mineral nitrogen, while the activity of cholinesterase on these nitrogen sources decreases 1.5--2.0 times. Yeast extract as a nitrogen source increases biomass accumulation by a factor of 2.5 and does not supress synthesis of cholinesterase. The concentration of the enzyme synthesized per unit biomass on the medium with yeast extract is the same as on the medium containing ammonium phosphate. The effect of amino acids and amides, i.e. beta-alanine, proline, amides of aspartic and glutamic acids, and their mixtures, is similar to the action of yeast extract: they stimulate biomass accumulation and do not inhibit synthesis of the enzyme. Other amino acids supress synthesis of cholinesterase. The amount of accumulated biomass in the presence of glutamic acid is twice as high as in the case of any other amino acid, and three times as high as on the medium containing ammonium phosphate. Similar action of glutamic acid is manifested when it is used in mixtures with other amino acids. On the medium containing glutamic acid as a sole source of nitrogen, an increase in biomass production is accompanied with a decrease in biosynthesis of the enzyme by 50%. Repression of the biosynthesis is less if glutamic acid is added in mixtures with proline, beta-alanine and asparagine.

Arthrobacter↗
PubMed1987

Effect of zinc ions on tRNA structure. I. Reversed-phase chromatography.

The effect of zinc on the chromatographic behavior of four tRNAs was examined on RPC-5 and Aminex A-28 columns. RPC-5 contains dichlorodifluoroethylene beads coated with a quaternary ammonium compound where the substituents are: R1 = methyl, and R2-4 = C8-10 hydrocarbons. Aminex A-28 contains quaternary ammonium covalently attached to styrene-divinylbenzene copolymer lattice and R1-3 are methyl groups. The retentions of tRNAVal, tRNAIle, and tRNALys of E. coli and yeast tRNAPhe on RPC-5 were all markedly increased by Zn2+ ions. In contrast, no increased retention due to Zn2+ was observed when tRNAPhe was chromatographed on Aminex A-28. A model for chromatography on RPC-5 is developed which treats the elution behavior of tRNAs from this matrix as the sum of ion-exchange and hydrophobic interactions. The chromatography of tRNA in the presence and absence of Zn2+ is interpreted in terms of this model and the effects of sodium chloride concentration, temperature, and pH were explored as the experimental variables. These experiments suggest that in the absence of Zn2+ tRNA does not interact appreciably with the hydrophobic surface of the column. The addition of Zn2+ has three effects on chromatography: a decrease in the number of anionic sites on the tRNA which interact with the positively charged ammonium ion, an increase in affinity of the tRNA for these ionic sites, and an increase in affinity of tRNA for hydrophobic sites on the column. All three effects were fully reversed by the addition of Cd2+ (10 mM) or Mg2+ (35 mM), but only partially reversed at lower concentrations of these competing ions. These results show that chromatography on RCP-5 can be a sensitive physical chemical technique for examination of the structure of tRNA, and probably for other nucleic acids as well.

Cadmium↗
PubMed1980

Analytical survey of N-nitroso contaminants in pesticide products.

1. Levels of N-nitroso dialkylamines in dinitroaniline derivatives were high (up to 153 mg/kg) in the past, but have been decreased considerably in current production, due to process changes. 2. Butralin and pendimethalin contain significant amounts of N-nitroso parent compounds. 3. Most dimethylamine salts of phenoxyalkanoic acids presently contain low or non-detectable levels of NDMA. 4. Quaternary ammonium compounds contain NDMA levels up to 16.8 mg/kg. 5. Two morpholine derivatives appear to contain N-nitrosomorpholine. 6. The triethanolamine salt of dinoseb contains over 200 mg/kg N-nitrosodiethanolamine. 7. A large number of amides, carbamates, organophosphates, triazines, urea derivatives and miscellaneous nitrogen-containing pesticides do not contain N-nitrosamines above 1 mg/kg. 8. Most N-nitroso contaminants in pesticides can be avoided by simple process changes and the elimination of nitrite salts in the formulation.

Chromatography, Gas↗
PubMed2003

Degradation of benzyldimethylalkylammonium chloride by Aeromonas hydrophila sp. K.

AIMS: The aim of this work was to study the biodegradation of benzyldimethylalkylammonium chloride (BAC) by Aeromonas hydrophila sp. K, an organism isolated from polluted soil and capable of utilizing BAC as sole source of carbon and energy. METHODS AND RESULTS: High performance liquid chromatography and gas chromatography-mass spectrometry (GC-MS) analysis was used to study BAC degradation pathway. It was shown that during BAC biodegradation, formation of benzyldimethylamine, benzylmethylamine, benzylamine, benzaldehyde and benzoic acid occurred. Formation of benzyldimethylamine as the initial metabolite suggested that the cleavage of Calkyl-N bond occurred as the first step of BAC catabolism. Liberation of benzylmethylamine and benzylamine likely resulted from subsequent demethylation reactions, followed by deamination with formation of benzaldehyde. Benzaldehyde was rapidly converted into benzoic acid, which was further degraded. CONCLUSIONS: Aer. hydrophila sp. K is able to degrade BAC. A degradation pathway for BAC and related compounds is proposed. SIGNIFICANCE AND IMPACT OF STUDY: These findings are significant for understanding biodegradation pathways of benzyl-containing quaternary ammonium compounds.

Aeromonas hydrophila↗
PubMed2001

Efficacy of commonly used disinfectants for the inactivation of calicivirus on strawberry, lettuce, and a food-contact surface.

Norwalk and Norwalk-like viruses (NLVs) are important causes of foodborne gastroenteritis in restaurant-related outbreaks. Efficacy of common disinfection methods against these viruses on food-contact surfaces and fresh produce is not known partially because of their nonculturability. Seven commercial disinfectants for food-contact surfaces and three sanitizers for fruits and vegetables were tested against cultivable feline calicivirus (FCV). Disks of stainless steel, strawberry, and lettuce were contaminated with known amounts of FCV. The disinfectants were applied at one, two, and four times the manufacturer's recommended concentrations for contact times of 1 and 10 min. The action of disinfectant was stopped by dilution, and the number of surviving FCVs was determined by titration in cell cultures. An agent was considered effective if it reduced the virus titer by at least 3 log10 from an initial level of 10(7) 50% tissue culture infective dose. None of the disinfectants was effective when used at the manufacturer's recommended concentration for 10 min. Phenolic compounds, when used at two to four times the recommended concentration, completely inactivated FCV on contact surfaces. A combination of quaternary ammonium compound and sodium carbonate was effective on contact surfaces at twice the recommended concentration. Rinsing of produce with water alone reduced virus titer by 2 log10. On artificially contaminated strawberry and lettuce, peroxyacetic acid and hydrogen peroxide was the only effective formulation when used at four times the manufacturers' recommended concentration for 10 min. These findings suggest that FCV and perhaps NLVs are very resistant to commercial disinfectants. However, phenolic compounds at two to four times their recommended concentrations appear to be effective at decontaminating environmental surfaces and may help control foodborne outbreaks of calicivirus in restaurants.

Caliciviridae↗
PubMed2006

Inhibitory effect of ammonium tetrathiotungstate on tyrosinase and its kinetic mechanism.

Tyrosinase requires two copper ions at the active site, in order to oxidize phenols to catechols. In this study, the inhibitory effect of the copper-chelating compound, ammonium tetrathiotungstate (ATTT), on the tyrosinase activity was investigated. ATTT was determined to inactivate the activity of mushroom tyrosinase, in a dose-dependent manner. The kinetic substrate reaction revealed that ATTT functions as a kinetically competitive inhibitor in vitro, and that the enzyme-ATTT complex subsequently undergoes a reversible conformational change, resulting in the inactivation of tyrosinase. In human melanin-producing cells, ATTT evidenced a more profound tyrosinase-inhibitory effect than has been seen in the previously identified tyrosinase inhibitors, including kojic acid and hydroquinone. Our results may provide useful information for the development of whitening agent.

Agaricales↗
PubMed1997

Plasmids and bacterial resistance to biocides.

Plasmid-encoded bacterial resistance to antibiotics and to anions and cation (including important mercurial and silver compounds) has been widely studied. Plasmid-mediated resistance to organic cationic agents which are important biocides has been described for chlorhexidine and quaternary ammonium compounds (and also for the less important acridine, diamidines and ethidium bromide) in antibiotic-resistant Staphylococcus aureus and Staph. epidermidis strains. Plasmids may also encode reduced biocide susceptibility of Gram-negative bacteria, but intrinsic resistance is likely to be of greater significance. Antibiotic resistance and biocide resistance may be linked but this is not always found clinically.

Anti-Infective Agents, Local↗
PubMed1979

Prevention of intravascular thrombus formation on plastic catheters with heparin-benzalkonium complex: in vivo and in vitro studies.

A complex of heparin and a quaternary ammonium compound dissolved in an organic solvent was investigated for its potential ability to prevent clotting on the surface of plastic catheters. Despite the complexing of heparin to ammonium, anticoagulant activity remained on in vitro testing. Both the heparin complex and its organic solvent alone partially prevented catheter thrombus formation when tested in an in vivo animal model system. Neither, however, was totally effective in preventing thrombosis.

Animals↗
PubMed1994

[Model tests for effectiveness assay of disinfectants on surfaces. III. Dependence of test results on the type of substances and the test microbes (Staphylococcus aureus, Mycobacterium terrae)].

A new test method for surface disinfectants was applied to investigate the efficacy of the most important active components of disinfectants to Staphylococcus aureus and Mycobacterium terrae. The test germs were embedded in coagulated blood. Frosted glass served as test surface. The disinfection was performed by applying a fixed amount of the disinfectant and mixing it with the contamination by rubbing. The number of surviving germs was determined quantitatively. Generally, the two test germs showed a distinctly different behaviour towards the active substances applied. Mycobacteria proved to be clearly more resistant than staphylococci, except with formaldehyde and the cresol-soap solution. The formaldehyde, the mycobacteria were only a little more resistant, while to cresol-soap solution they were even a little more sensitive than were staphylococci. Compounds containing active chloride showed a sufficient effect on mycobacteria only if the consumption of the active component by blood was nearly excluded. The quaternary ammonium compound and glyoxal, even the high concentrations, showed a totally insufficient efficacy to mycobacteria. The results shall provide the basis for a new guideline to be established by the Federal Health Office concerning the efficacy testing of surface disinfectants effective against mycobacteria, especially tuberculosis bacteria.

Chlorine↗
PubMed1981

[Effects of mecamylamine and pempidine, secondary and tertiary amines, on the spinal reflex of cats (author's transl)].

The ganglionic blocking effects of the secondary and tertiary amines, mecamylamine and pempidine, on the spinal reflex of cats of both sexes were investigated. These blocking effects were then compared with findings in the quaternary ammonium compounds such as tetraethylammonium (TEA) and decamethonium (C10). Mecamylamine (5 mg/kg) and pempidine (1 mg/kg) inhibited spinal reflex potentials such as the monosynaptic reflex (MSR), the polysynaptic reflex (PSR) and the dorsal root reflex (DRR). Maximal inhibition occurred 40 min after intravenous administration these drugs. In the case of mecamylamine, the inhibited potentials recovered gradually after reaching the maximum inhibition. However, the inhibitory effect of pempidine was prolonged, and recovery of the potentials did not occur for 6 min or longer. Although 10 mg/kg of C10 and 0.025 mg/kg of nicotine transiently inhibited the MSR and PSR, these compounds had no effect on the DDR. TEA produced prolonged inhibition of the MSR and PSR, and slightly enhanced the DRR. These results demonstrated the differences in DRR responses to secondary and tertiary amines, and quaternary ammoniums.

Animals↗