Effect of anionic surfactants on some dehydrogenases and phosphofructokinase activities in loach embryos

Glucose-6-phosphatedehydrogenase (EC 1.1.1.49), lactatedehydrogenase (EC 1.1.1.27), malate dehydrogenase (EC 1.1.1.38) and phosphofructokinase (EC 2.7.1.11) activities in loach (Misgurnus fossilis L.) embryos were determined after incubation of the latter in the media containing surfactants--alkyl benzol sulphonates NP-1, NP-3, RAS and secondary alkyl sulphate "Progress". The determined activities changed under the influence of the used surfactants. Minimal changes of the activities were observed in the media with sulphonol np-1, and maximal ones--with the "Progress" preparation. The dependence is revealed of the enzyme activities changes upon the surfactant concentration and the stage of the embryo development.     

Bacterial destruction of anionic sulfoethoxylate surfactants

A Pseudomonas putida strain G was isolated and its activity in the destruction of sulfoethoxylates (surfactants) was studied as a function of the cultivation conditions. Ultrastructural changes were found in the cells utilizing sulfoethoxylates. Sulfoethoxylates were found to be decomposed by P. putida G via two pathways: (a) desulfation of the molecule and (b) cleavage of the alkyl ester bond. The intermediate products were not toxic and did not pollute the habitat. The strain can be used for microbiological purification of sewage.     

ADP-ribosylation of bradykinin and effects on its biological activities

We investigated the ADP-ribosylation of bradykinin by hen liver nuclear ADP-ribosyltransferase. Two Arg residues of the peptide were modified by this enzyme. Arg1 was preferentially modified as compared to Arg9; the Vmax/Km for Arg1 was 3 times higher than that for Arg9. These results were given support by data observed in experiments with des-Arg1 and des-Arg9 bradykinin; the Vmax/Km for des-Arg9 bradykinin was 3 times that for des-Arg1 bradykinin. ADP-ribosylation suppressed the biological activity of bradykinin, as related to both binding and contractile activities. The extent of ADP-ribosylation-induced suppression of both activities was higher in the case of the modification of Arg1 than that of Arg9. In view of the observation of ADP-ribosyltransferase activity in skeletal, cardiac, and smooth muscles (Soman, G. et al. (1984) Biochem. Biophys. Res. Commun. 120, 973-980; Shimoyama, M. et al. (1987) in The 8th International Symposium on ADP-Ribosylation, Texas, abstract p. 13), bradykinin functioning in the contraction of smooth muscle may be modified in this way in vivo.     

Effect of ethyleneoxide groups of anionic surfactants on lipase activity

The use of enzymes in laundry and dish detergent products is growing. Such tendency implies dedicated studies to understand surfactant‐enzyme interactions. The interactions between surfactants and enzymes and their impact on the catalytic efficiency represent a central problem and were here evaluated using circular dichroism, dynamic light scattering, and enzyme activity determinations. This work focuses on this key issue by evaluating the role of the ethyleneoxide (EO) groups of anionic surfactants on the structure and activity of a commercial lipase, and by focusing on the protein/surfactant interactions at a molecular level. The conformational changes and enzymatic activity of the protein were evaluated in the presence of sodium dodecyl sulfate (SDS also denoted as SLE₀S) and of sodium lauryl ether sulfate with two EO units (SLE₂S). The results strongly suggest that the presence of EO units in the surfactant polar headgroup determines the stability and the activity of the enzyme. While SDS promotes enzyme denaturation and consequent loss of activity, SLE₂S preserves the enzyme structure and activity. The data further highlights that the electrostatic interactions among the protein groups are changed by the presence of the adsorbed anionic surfactants being such absorption mainly driven by hydrophobic interactions. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1276–1282, 2016     

Effect of rare earth cations on bactericidal activity of anionic surfactants

Summary Rare earth metal cations are antibacterially synergistic with anionic surfactants, yielding mixtures that have bactericidal activity against a variety of gram-positive and gram-negative bacteria at minimum concentrations ranging from 16 to 125 g/ml. Uptake of surfactant byEscherichia coli increases in the presence of lanthanum, suggesting that the role of rare earth metal cations is to reduce the net negative surface charge on the bacteria, thereby increasing the affinity between the negatively charged surfactant and the bacterial surface.     

Atomic-scale structure and electrostatics of anionic palmitoyloleoylphosphatidylglycerol lipid bilayers with Na+ counterions

Anionic palmitoyloleoylphosphatidylglycerol (POPG) is one of the most abundant lipids in nature, yet its atomic-scale properties have not received significant attention. Here we report extensive 150-ns molecular dynamics simulations of a pure POPG lipid membrane with sodium counterions. It turns out that the average area per lipid of the POPG bilayer under physiological conditions is approximately 19% smaller than that of a bilayer built from its zwitterionic phosphatidylcholine analog, palmitoyloleoylphosphatidylcholine. This suggests that there are strong attractive interactions between anionic POPG lipids, which overcome the electrostatic repulsion between negative charges of PG headgroups. We demonstrate that interlipid counterion bridges and strong intra- and intermolecular hydrogen bonding play a key role in this seemingly counterintuitive behavior. In particular, the substantial strength and stability of ion-mediated binding between anionic lipid headgroups leads to complexation of PG molecules and ions and formation of large PG-ion clusters that act in a concerted manner. The ion-mediated binding seems to provide a possible molecular-level explanation for the low permeability of PG-containing bacterial membranes to organic solvents: highly polar interactions at the water/membrane interface are able to create a high free energy barrier for hydrophobic molecules such as benzene.     

Analysis of supercooling activities of surfactants

Supercooling-promoting activities (SCAs) of 25 kinds of surfactants including non-ionic, anionic, cationic and amphoteric types were examined in solutions (buffered Milli-Q water, BMQW) containing the ice nucleation bacterium (INB) Erwinia ananas, silver iodide (AgI) or BMQW alone, which unintentionally contained unidentified ice nucleators, by a droplet freezing assay. Most of the surfactants exhibited SCA in solutions containing AgI but not in solutions containing the INB E. ananas or BMQW alone. SCAs of many surfactants in solutions containing AgI were very high compared with those of previously reported supercooling-promoting substances. Cationic surfactants, hexadecyltrimethylammonium bromide (C16TAB) and hexadecyltrimethylammonium chloride (C16TAC), at concentrations of 0.01% (w/v) exhibited SCA of 11.8 °C, which is the highest SCA so far reported. These surfactants also showed high SCAs at very low concentrations in solutions containing AgI. C16TAB exhibited SCA of 5.7 °C at a concentration of 0.0005% (w/v).     

The biological properties of lysine-derived surfactants

Summary. We examine the effects of aquatic toxicity on Daphnia magna, the antimicrobial activity of new anionic lysine-derivative surfactants, and the influence of different-sized counterions associated with the surfactants. Surfactants with Tris and Lithium had less of a toxic effect on Daphnia, while all surfactants proved highly active against yeasts and the gram-negative bacteria Bordetella bronchiseptica. Counterion size was found to have no effect on aquatic toxicity or antimicrobial activity.     

Bacterial cell hydrophobicity is modified during the biodegradation of anionic surfactants

Abstract A biphasic increase in surface hydrophobicity of the surfactant-biodegrading bacterium Pseudomonas C12B has been correlated with biodegradation of the primary alkyl sulphate, sodium dodecyl sulphate. Using both hydrophobic interaction chromatography and microbial adhesion to hydrocarbon to measure surface hydrophobicity, it was shown that the first phase coincides with production of the primary metabolite dodecan-1-ol. The direct addition of dodecan-1-ol to Pseudomonas C12B resulted in the instantaneous increase in surface hydrophobicity, with a subsequent decrease which coincided with dodecan-1-ol biodegradation. In contrast, incubation of Pseudomonas C12B with sodium dodecane sulphonate, a non-metabolizable surfactant analogue of SDS, or the growth-supporting carbon source sodium pyruvate did not alter the surface hydrophobicity. These data are interpreted in terms of a model in which the hydrophobic metabolite dodecan-1-ol enters the bacterial membranes, thus increasing surface hydrophobicity and that these surfactant-biodegradation-dependent changes in bacterial surface hydrophobicity are correlated with reversible attachment of the bacteria to sediment surfaces.     

表面活性剂对海洋微生物溶菌酶活性的影响

以海洋微生物溶菌酶（ⅧL）为研究对象,分别检验几种表面剂对MBL活性的影响,着重研究烷基多苷（APG）对其活性的影响。结果表明,APG与阳离子烷基多苷（矾PG）分别提高MBL相对酶活性为21％,15％,SDS降低该酶活性约为15％,Tween20和Tween80对MBL活性的影响不明显。MBL含量大于5．0mg／mL时,对大肠杆菌、金黄色葡萄、白色念珠球菌有抑菌作用。0．5％～1．5％的APG无明显抑菌作用。将5．0mg／mMBL与1．0mg／mLAPG复配后（简称CEP）,发现APG能明显增强MBL抑菌作用,CEP具有较好地杀菌作用;CEP在54℃培养箱中放置14d后,其杀菌率保持不变,说明CEP的杀菌性能的稳定性良好。     

Formation of mutagens by sorbic acid-nitrite reaction: effects of reaction conditions on biological activities

Conditions of the reaction between sorbic acid and sodium nitrite generating mutagenic principles were examined. In the rec-assay and the Ames reversion assay, the maximal mutagenic activity was obtained in a pH range of 3.5–4.2. Mutagenic and growth-inhibitory activities of five C-nitro and C-nitroso compounds were studied. The product Y, 2-methyl-1,4-dinitropyrrole, was the strongest mutagen among them.     

Antioxidant and cytotoxic activities of canadine: biological effects and structural aspects

The cytotoxic effects of four alkaloids, berberine, canadine, anonaine, and antioquine were evaluated using three different cell cultures, a primary culture (rat hepatocytes) and two cell lines (HepG2 and HeLa). Our results indicate that berberine, anonaine, and antioquine possess a significant the cytotoxic effect. In contrast, canadine does not possess cytotoxic effect at concentrations tested here. A molecular modeling study indicates that the quaternary nitrogen, the aromatic polycyclic and planar structure of berberine could be the pharmacophoric patron to produce the cytotoxic effect. In parallel our results demonstrated that canadine possess a significant antioxidant activity. Stereoelectronic aspects of this alkaloid were found to be closely related to those displayed by alpha-tocopherol and its water-soluble analogue trolox. The antioxidant activities of canadine, combined with its low-toxic effect, indicated that the potential of this alkaloid as a novel class of antioxidant agent is very interesting and deserves further research.     

Influence of coprecipitation and interactions with anionic surfactants on the activity of plant phospholipase D.

The effects of two surfactants (sodium dodecyl sulfate and sodium dodecyl dioxyethylene sulfate) of similar structure but differing water solubility (of their calcium salts) on the enzymatic activity of cabbage phospholipase D have been studied. The solubility difference is insignificant because the two surfactants activate phospholipase D similarly. To elucidate the mechanism of their influence on the enzyme, the phase behavior in the reaction media and the interactions of the surfactants with the enzyme were investigated by potentiometry and by light scattering and UV spectroscopy. Calcium dodecyl dioxyethylene sulfate (which is more soluble in water than calcium dodecyl sulfate) precipitates in the presence of phosphatidylcholine, the substrate of the enzymatic reaction. In the reaction media phospholipase D was involved into a precipitate consisting of calcium salts of the surfactants and phosphatidylcholine that might be interpreted as its immobilization. In addition, the surfactants were adsorbed on the enzyme, unfolding the globular enzyme molecule due to electrostatic repulsion between adsorbed surfactant anions. The observed increase in the functional activity of phospholipase D is accounted for by transfer to an optimal tertiary structure for the enzyme molecule in the course of consecutive conformational transitions induced by the surfactants.     

Bacteria-degraders as the base of an amperometric biosensor for detection of anionic surfactants

Several strains belonging to genera Pseudomonas and Achromobacter and characterized by the ability to degrade anionic surfactants were tested as potential bases of microbial biosensors for surfactant detection. For each strain the substrate specificity and stability of sensor signals were studied. The total amount of the substrates tested (including carbohydrates, alcohols, aromatics, organic acids, etc.) was equal to 60; the maximal signals were observed towards the anionic surfactants. The lower limit of detection for sodium dodecyl sulfate used as a model surfactant was in the field of 1 microM for all the strains. The created microbial biosensor model can extend the practical possibilities for rapid evaluation of surfactants in water media.     

Resonance Rayleigh scattering method for the determination of chitosan with some anionic surfactants

In weak acidic buffer medium, chitosan binding with an anionic surfactant, such as sodium dodecyl benzene sulphonate (SDBS), sodium lauryl sulphate (SLS) or sodium dodecyl sulphonate (SDS), can result in a significant enhancement of resonance Rayleigh scattering (RRS) intensity. The results showed that under optimum conditions the enhanced RRS intensity is proportional to the concentration of chitosan in the range 0.10–20.0 µg/mL for SDBS, 0.27–15.0 µg/mL for SLS and 0.20–15.0 µg/mL for SDS. Among these, the sensitivity of SDBS is the highest and its detection limit for chitosan is 29 ng/mL, while those of SLS and SDS are 83 and 61 ng/mL, respectively. The method has good selectivity and was applied to the determination of trace amounts of chitosan in practical samples with satisfactory results. Therefore, a simple and convenient method with high sensitivity and selectivity for the determination of chitosan was established. Copyright © 2008 John Wiley & Sons, Ltd.