Surfactant Activity Research Articles

Adjuvant Pluronic F68 Is Compatible with a Plant Root-Colonizing Probiotic, Pseudomonas chlororaphis O6

Plant probiotic bacteria are being increasingly used to maximize both the productivity and quality of field crops. Pseudomonas chlororaphis O6 (PcO6) is a plant root colonizer with probiotic activities. This bacterium produces an array of metabolites, including a group of phenazines that are functional in plant protection. The paper reports responses of PcO6 to a nonionic triblock copolymer surfactant, Pluronic F68. This Pluronic exhibits membrane “healing” activity and improves cryopreservation recovery in eukaryotic cells. The product is FDA-approved and is applied as an adjuvant in formulations used in agriculture, medicine, and biotechnology. Growth of PcO6 on lysogeny broth at 25 °C was unhindered by 0.1 and 1.0 g/L F68, reduced at 10 g/L, and with significant inhibition at 100 g/L F68; micelle formation could account for inhibited growth at higher doses. Phenazine production was not changed by F68, whereas the surfactant activity of F68 induced the spread of bacterial colonization on 0.5% agar. Exposure of cells to fluorescein-labeled F68 resulted in intense fluorescence, stable to washing, showing a direct association of the Pluronic with the bacterium. However, neither protection nor harm was found for PcO6 cells suspended in either 0.1% or 1% F68 after three freeze (−20 °C)/thaw cycles. These findings suggest that F68 could be compatible for use in agricultural formulations with little effect on probiotics such as PcO6.

Identification of the Major Protein Components of Human and Cow Saliva

Cows produce saliva in very large quantities to lubricate and facilitate food processing. Estimates indicate an amount of 50–150 L per day. Human saliva has previously been found to contain numerous antibacterial components, such as lysozyme, histatins, members of the S-100 family and lactoferrin, to limit pathogen colonization. Cows depend on a complex microbial community in their digestive system for food digestion. Our aim here was to analyze how this would influence the content of their saliva. We therefore sampled saliva from five humans and both nose secretions and saliva from six cows and separated the saliva on SDS-PAGE gradient gels and analyzed the major protein bands with LC-MS/MS. The cow saliva was found to be dominated by a few major proteins only, carbonic anhydrase 6, a pH-stabilizing enzyme and the short palate, lung and nasal epithelium carcinoma-associated protein 2A (SPLUNC2A), also named bovine salivary protein 30 kDa (BSP30) or BPIFA2B. This latter protein has been proposed to play a role in local antibacterial response by binding bacterial lipopolysaccharides (LPSs) and inhibiting bacterial growth but may instead, according to more recent data, primarily have surfactant activity. Numerous peptide fragments of mucin-5B were also detected in different regions of the gel in the MS analysis. Interestingly, no major band on gel was detected representing any of the antibacterial proteins, indicating that cows may produce them at very low levels that do not harm the microbial flora of their digestive system. The nose secretions of the cows primarily contained the odorant protein, a protein thought to be involved in enhancing the sense of smell of the olfactory receptors and the possibility of quickly sensing potential poisonous food components. High levels of secretory IgA were also found in one sample of cow mouth drippings, indicating a strong upregulation during an infection. The human saliva was more complex, containing secretory IgA, amylase, carbonic anhydrase 6, lysozyme, histatins and a number of other less abundant proteins, indicating a major difference to the saliva of cows that show very low levels of antibacterial components, most likely to not harm the microbial flora of the rumen.

Colloid-chemical properties of surfactant–nitric acid–water systems

The behavior of the surfactants Tween 80, SaS and alkyl betaine in aqueous and nitric acid environments as promising additives for nitrate leaching of hard-to-process ore concentrates of non-ferrous metals was studied. The influence of surfactant concentration (0.04–1.28 g/dm3), nitric acid concentration (0.1–10 g/dm3) and temperature (295–343 K) on the surface tension, critical micelle concentration (CMC), pH and optical density of aqueous surfactant solutions and surfactant–HNO3–H2O systems was found. The critical micelle concentration of the surfactants used was estimated. A positive effect of nitric acid on the surface activity of surfactants was discovered, which manifests itself in a decrease in both the CMC and the surface tension at the liquid–gas interface. The values of surface activity and Gibbs energy of surfactant micelle formation in aqueous and nitric acid media were calculated. Associative processes in the solutions and compositions were confirmed by measuring the optical density of the systems under study.

Evaluation of antioxidant and anti-tyrosinase activities of surfactant and alcohol extracted Combretum Indicum leaves

Combretum Indicum (CI), which contains numerous bioactive compounds, has been used in traditional medicine for a variety of reasons, including the treatment of skin conditions. This study investigates the antioxidant and anti-tyrosinase activities of CI leaves extracted using different surfactants (Triton X-100 and Vitamin E TPGS) at concentrations of 1%, 2%, and 3%, as well as various alcohol solvents (acetone, methanol, and ethanol) at concentrations of 50%, 70%, and 90%. The antioxidant activity of the extracts has been evaluated using Total Phenolic Content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH), while the anti-tyrosinase activity was assessed through a mushroom tyrosinase inhibition assay. Prior to analysis, CI leaves had been macerated, extracted, and freeze-dried. The research established that ethanol at a concentration of 50% is the optimum solvent to extract CI leaves, as it demonstrated good antioxidant and anti-tyrosinase action with a high percentage of yield and total phenolic content. As a result, the outcomes of this study contribute to a better understanding of the potential applications of CI leaf extract in cosmetics, notably in the treatment of oxidative stress and hyperpigmentation. Further study and development in this field could lead to the creation of effective and natural cosmetic products produced from CI leaves that have antioxidant and anti-tyrosinase effects.

Study on synthesis, surface activity and quantum chemical properties of anionic-nonionic Gemini surfactant

In this work, Gemini surfactants with different hydrophobic tails and spacer groups were designed and synthesized. The structures were verified by 1H NMR spectrum and mass spectrometry. The modulation of the experimental results of micellar thermodynamics and surface activity by the molecular structure has been thoroughly discussed and studied. Furthermore, the electrostatic potential results explain Gemini surfactants have a very efficient ability to reduce surface tension. The molecular polarity index (MPI) has been shown to be used to cost-effectively evaluate the surface activity of Gemini surfactants. It is hoped that the work will promote the structural design and industrial application of Gemini surfactants.

Establishment of a transparent soil system to study Bacillus subtilis chemical ecology

Bacterial secondary metabolites are structurally diverse molecules that drive microbial interaction by altering growth, cell differentiation, and signaling. Bacillus subtilis, a Gram-positive soil-dwelling bacterium, produces a wealth of secondary metabolites, among them, lipopeptides have been vastly studied by their antimicrobial, antitumor, and surfactant activities. However, the natural functions of secondary metabolites in the lifestyles of the producing organism remain less explored under natural conditions, i.e. in soil. Here, we describe a hydrogel-based transparent soil system to investigate B. subtilis chemical ecology under controllable soil-like conditions. The transparent soil matrix allows the growth of B. subtilis and other isolates gnotobiotically and under nutrient-controlled conditions. Additionally, we show that transparent soil allows the detection of lipopeptides production and dynamics by HPLC-MS, and MALDI-MS imaging, along with fluorescence imaging of 3-dimensional bacterial assemblages. We anticipate that this affordable and highly controllable system will promote bacterial chemical ecology research and help to elucidate microbial interactions driven by secondary metabolites.

Identification of the lipodepsipeptide selethramide encoded in a giant nonribosomal peptide synthetase from a Burkholderia bacterium

Bacterial natural products have found many important industrial applications. Yet traditional discovery pipelines often prioritize individual natural product families despite the presence of multiple natural product biosynthetic gene clusters in each bacterial genome. Systematic characterization of talented strains is a means to expand the known natural product space. Here, we report genomics, epigenomics, and metabolomics studies of Burkholderia sp. FERM BP-3421, a soil isolate and known producer of antitumor spliceostatins. Its genome is composed of two chromosomes and two plasmids encoding at least 29 natural product families. Metabolomics studies showed that FERM BP-3421 also produces antifungal aminopyrrolnitrin and approved anticancer romidepsin. From the orphan metabolome features, we connected a lipopeptide of 1,928 Da to an 18-module nonribosomal peptide synthetase encoded as a single gene in chromosome 1. Isolation and structure elucidation led to the identification of selethramide which contains a repeating pattern of serine and leucine and is cyclized at the side chain oxygen of the one threonine residue at position 13. A (R)-3-hydroxybutyric acid moiety decorates the N-terminal serine. Initial attempts to obtain deletion mutants to probe the role of selethramide failed. After acquiring epigenome (methylome) data for FERM BP-3421, we employed a mimicry by methylation strategy that improved DNA transfer efficiency. Mutants defective in selethramide biosynthesis showed reduced surfactant activity and impaired swarming motility that could be chemically complemented with selethramide. This work unveils a lipopeptide that promotes surface motility, establishes improved DNA transfer efficiency, and sets the stage for continued natural product identification from a prolific strain.

Synthesis and surface activity of novel amino acid surfactants

AbstractAmino acid surfactants (AASs) based on environmentally friendly biomasses have the characteristics of renewable, easy biodegradation, antibacterial and low toxicity, and have been widely used in daily chemicals, pharmaceuticals, and other fields. This study concerned the use of octanal and amino acids as raw materials. In addition, seven types of amino acid‐based surfactants, through Collins reagents, Wittig‐Hornor reaction, and aza‐Micheal addition reaction, and amino acid head groups were connected with the alkyl chain by the CN bond. The structures were confirmed by infrared spectroscopy (FT‐IR) and nuclear magnetic resonance spectroscopy (1HNMR). Its surface activity and adsorption properties are evaluated. The physical properties of amino acid‐based surfactants were tested by surface tension and dynamic contact angle. The results demonstrated that histidine‐based amino acid surfactant (C8His) has the lowest critical micelle concentration (CMC) and surface tension at CMC (γCMC), 0.39 mmol L−1 and 28.79 mN L−1, respectively. Amino acid residues contribute to reducing the critical micelle concentration of surfactant. The interfacial adsorption of glycine‐based amino acid surfactant (C8Gly) significantly improved with the increase in temperature, so the surface tension decreased significantly. In addition, sodium chloride could effectively enhance the interfacial adsorption, and the gas–liquid interfacial tension and contact angle of AASs decrease.

Sugar-Based Monoester Surfactants: Synthetic Methodologies, Properties, and Biological Activities.

Glycolipids are biocompatible and biodegradable amphiphilic compounds characterized by a great scientific interest for their potential applications in various technological areas, including pharmaceuticals, cosmetics, agriculture, and food production. This report summarizes the available synthetic methodologies, physicochemical properties, and biological activity of sugar fatty acid ester surfactants, with a particular focus on 6-O-glucose, 6-O-mannose, 6-O-sucrose, and 6'-O-lactose ones. In detail, the synthetic approaches to this class of compounds, such as enzymatic lipase-catalyzed and traditional chemical (e.g., acyl chloride, Steglich, Mitsunobu) esterifications, are reported. Moreover, aspects related to the surface activity of these amphiphiles, such as their ability to decrease surface tension, critical micelle concentration, and emulsifying and foaming ability, are described. Biological applications with a focus on the permeability-enhancing effect across the skin or mucosa, antimicrobial and antifungal activities, as well as antibiofilm properties, are also presented. The information reported here on sugar-based ester surfactants is helpful to broaden the interest and the possible innovative applications of this class of amphiphiles in different technological fields in the future.

Pullusurfactins A‒C, new biosurfactants produced by Aureobasidium pullulans A11231-1-58 from Chrysanthemum boreale Makino.

Biosurfactants have found widespread use across multiple industrial fields, including medicine, food, cosmetics, detergents, pulp, and paper, as well as the degradation of oil and fat. The culture broth of Aureobasidium pullulans A11231-1-58 isolated from flowers of Chrysanthemum boreale Makino exhibited potent surfactant activity. Surfactant activity-guided fractionation led to the isolation of three new biosurfactants, pullusurfactins A‒C (1‒3). Their chemical structures were established through the use of spectroscopic techniques, predominantly 1D and 2D NMR, in conjunction with mass measurements. We evaluated the surface tension activities of isolated compounds. At 1.0 mg l-1, these compounds showed high degrees of surfactant activity (31.15 dyne/cm, 33.75 dyne/cm, and 33.83 dyne/cm, respectively).

The Effect of Surfactants on the Removal of Ceria Particles in the Buff Clean Process

In this work, we have established a new buff clean method, using deionized water (DIW) with 2000 ppm surfactants to remove ceria particles from the surface of SiO2 after chemical mechanical polishing (CMP). Six kinds of surfactants have been compared. The SEM and AFM results show that with CAO and LAPAO, the ceria particles can be fully removed in the buff clean process. The molecular activity and adsorption energy of surfactants are calculated based on the density functional theory (DFT) to clarify the mechanism of the buff clean process. The surfactants adsorbing on the SiO2 surface can be fully removed after the buff clean process.

Structure–activity relationship on selective antibacterial activity of nonionic surfactants

AbstractThe antibacterial activity of surfactants is an important factor to consider for improving skin conditions in cosmetic and skin care products. In this study, we evaluated the antibacterial activity of 16 nonionic surfactants containing ethylene oxide, ester, and ether functional groups against Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). 12:0 MG ester and 6–12 diol, which showed antibacterial activity against both Staphylococci, had compact hydrophilic groups with low polarity. In contrast, 12:0 PEG‐10 ester and 12:0 Sor ester, which showed antibacterial activity only against S. aureus, had large hydrophilic groups and high polarity. These results suggest that the hydrophilicity and polarity of the surfactant may be involved in its antibacterial behavior against Staphylococci. These findings will be useful in the design of surfactant molecules and in the development of cosmetics and body cleansers that exhibit antibacterial activity only against S. aureus.

Biological Activity of Acinetobacter calcoaceticus IMV B-7241 Surfactants Synthesized in the Presence of Competitive Bacteria Bacillus subtilis BT-2

Currently, the effectiveness of technologies for microbial surfactants, which are characterized by a complex of practically valuable physicochemical and biological properties is lower than that of synthetic analogues. To reduce the cost of these products of microbial synthesis, industrial waste is used as substrates for their biosynthesis. In previous studies, it has been established that surfactants synthesized by Acinetobacter calcoaceticus IMV B-7241 on crude glycerol have lower antimicrobial activity compared to that obtained on purified glycerol. The main approaches to the regulation of the biological activity of microbial surfactants are their post-fermentation chemical modification, as well as the improvement of producer strains by methods of metabolic and genetic engineering. In recent years, numerous studies have appeared on the co-cultivation of producers of antimicrobial compounds with competitive microorganisms (biological inductors), in response to the presence of which the antimicrobial activity of the final product increases. Aim. To study the effect of live and inactivated cells of Bacillus subtilis BT-2, as well as the corresponding supernatant, on the antimicrobial and anti-adhesive activity and the ability to destroy biofilms of A. calcoaceticus IМV B-7241 surfactants synthesized in a medium with glycerol of different degrees of purification. Methods. The A. calcoaceticus IMV B-7241 strain was grown in a liquid mineral medium with purified and crude glycerol, into which live and inactivated B. subtilis BT-2 cells as well as the supernatant after growing the B. subtilis BT-2 strain (2.5—10%, v/v) were added. Surfactants were extracted from the supernatant of the culture liquid with Folch’s mixture. Anti-adhesive activity and the degree of destruction of biofilms were determined by the spectrophotometric method, and antimicrobial activity — by the indicator of the minimum inhibitory concentration. The activity of enzymes of surface-active aminolipids biosynthesis (NADP+-dependent glutamate dehydrogenase) and glycolipids (phosphoenolpyruvate (PEP)-carboxylase, PEP-synthetase, PEP-carboxykinas, trehalose-phosphate synthase) was analyzed in cell-free extracts obtained after сells sonication. Results. It was established that the introduction of inactivated B. subtilis BT-2 cells and supernatant into the medium with both substrates did not affect the indicators of the surfactant synthesis, while in the presence of live cells of the B. subtilis BT-2 strain in the medium with purified glycerol, a decrease in the concentration of the final product by 1.5 times, and in the culture medium with crude glycerol — an increase by1.4 times were observed compared to the indicators with no inductor. The study of the antimicrobial activity of surfactants showed that the most effective of the used inductors (live, inactivated cells, supernatant) were live cells of B. subtilis BT-2. The introduction of B. subtilis BT-2 strain live cells into the culture medium with both substrates was accompanied by the formation of surfactants, the minimum inhibitory concentrations of which in relation to bacterial (Bacillus subtilis BT-2, Staphylococcus aureus BMS-1, Proteus vulgaris PA-12, Enterobacter cloacae С-8) and yeast (Candida albicans D-6, Candida tropicalis PE-2) test-cultures were 3—23 times lower than established for those synthesized on the medium with no inductor. Anti-adhesive activity of surfactants obtained on purified and crude glycerol in the presence of all types of inductors was higher compared to those synthesized in the culture medium without inductors (cells adhesion of bacterial and yeast test-cultures on polyvinyl chloride was 13—70 and 33—96%, respectively). Introduction of live and inactivated B. subtilis BT-2 cells or the supernatant into A. calcoaceticus IMV B-7241 cultivation medium was accompanied by the synthesis of surfactants, in the presence of which the disruption of bacterial biofilms was on average 10-20% higher compared to using surfactants synthesized without an inductor. In the presence of B. subtilis BT-2 in the medium, in the cells of the A. calcoaceticus IMV B-7241 strain, the activity of NADP+-dependent glutamate dehydrogenase (a key enzyme of aminolipids biosynthesis) increased by 1.5—2 times, while the activity of biosynthesis of glycolipids enzymes remained practically at the same level as without an inductor. Such data indicate that the higher biological activity of surfactants obtained by A. calcoaceticus IMV B-7241 in the presence of biological inductors might be due to an increase in the content of aminolipids in their composition. Conclusions. This research has established the possibility of regulating the antimicrobial and anti-adhesive activity as well as the ability to disrupt biofilms of A. calcoaceticus IМV B-7241 surfactants by introducing competitive bacteria B. subtilis BT-2 into the culture medium. It is important that under such cultivation conditions, the antimicrobial activity of surfactants synthesized on toxic crude glycerol significantly increases.

CYTOGENETIC EFFECTS OF SURFACTANTS

Introduction. The widespread use of surfactants in economic activity and life has led to global pollution. The negative impact of surfactants on various characteristics of living organisms has been revealed, which makes a research on the safety of surfactants extremely relevant. Aim. The aim of this work was to study the genotoxic potential of anionic and cationic surfactants. Methods. The influence of anionic (sodium stearate and alkylbenzenesulpho-acid) and cationic (Praepagen TQ) surfactants on the value of the mitotic index, as well as on the regularity of mitosis and meiosis of Triticum aestivum L. cv. Odesa fantasy by standard cytogenetic methods. Main results. Under the action of surfactants in the root meristem of sprouts, the mitotic index significantly decreased and the number of cells containing chromosomal aberrations increased. Among the abnormalities at the ana-telophase stage, cells with lagging chromosomes, fragments, the formation of chromosomal bridges, and complex disorders were observed. These changes were directly proportional to the concentration of the drugs. The action of the cationic drug was less harmful than the action of both anionic drugs. Treatment of plants with surfactants led to a highly reliable increase in the proportion of abnormal MCPs in both the first and second division of meiosis, directly proportional to the concentration of surfactants applied. No differences were found between the first and second meiotic divisions in terms of the frequency of formation of defective MCPs. Both anionic surfactants had a stronger effect than the cationic one; with the use of alkylbenzenesulfonic acid, the degree of violations in microsporocytes was the greatest. Conclusions. A significant decrease in the mitotic index and an increase in the proportion of cells containing chromosomal aberrations in the root meristem of sprouts, as well as a significant increase in the proportion of abnormal MCPs in both the first and second division of meiosis, were found to be directly proportional to the concentration of surfactant. According to all the parameters studied, the action of the cationic drug “Praepagen TQ” was milder than the action of both anionic surfactants.

Self-aggregation of cationic gemini surfactants with amide groups in the spacer and variable alkyl chain length

AbstractSynthesis, aggregation parameters and antimicrobial activity of novel cationic gemini surfactants with two amide groups in gemini spacer structure and a variable number of carbon atoms in alkyl tails ranging from 12 to 15 are reported. The critical micelle concentration of gemini surfactants was determined using surface tension and electrical conductivity methods. The cmc values were found in the range 0.83 to 0.06 mM. The interfacial area, micelle ionisation degree and the Gibbs free energy per molecule and alkyl chain were calculated from the surface tension and conductivity curves. Particle size analysis using the dynamic light scattering method confirmed the formation of small spherical micelles 6–7 nm large in size for gemini surfactants with 12 and 13 carbon atoms in the alkyl chain. A large size above 50 nm was found for the aggregates composed of long-chain gemini molecules with 14 and 15 carbon atoms. The zeta potential of gemini surfactants shows a continuous increase with the increasing alkyl chain length. Micelle aggregation number of gemini surfactants correlates well with the hydrodynamic size data. Small aggregation number values were found for short-chain gemini molecules with 12 and 13 carbon atoms in the alkyl chain. Long-chain gemini molecules with 14 and 15 carbon atoms exhibit aggregate growth represented by an increase in the aggregation number values while maintaining the spherical or spheroidal shape of micelles. The investigations of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria and yeast indicate the increasing antimicrobial efficiency towards the short-chain surfactant with 12 carbon atoms in the alkyl chain. A possible cut-off effect presence is proposed to explain the dependence of antimicrobial activity on the surfactant alkyl tail length.

Effect of nanoparticles and silicone surfactants on the foam properties and wettability of dust removal foam

Foam has been widely used in coal mine dust control. However, its instability is still an issue in its application, and some surfactants components in foaming agents, such as fluorocarbons, are harmful to the environment. In this study, the environmentally friendly alkyl glycoside(APG0814) and cetyltrimethylammonium bromide (CTAB) were used as the foaming agents, and modified hydrophilic SiO2 nanoparticles were added to improve foam stability. Also, the surface tension, foam properties, contact angle and intermolecular interaction of APG0814/CTAB/SiO2 dispersion were studied. The experimental results showed that the appropriate concentration of CTAB combined with nanoparticles played a key role in stabilizing the foam. The surface tension of the foaming liquid increased with the increase in nanoparticles and CTAB, leading to the deterioration of foaming properties. The silicone surfactant GT-248 was added to the APG0814/CTAB/SiO2 dispersion to further improve the surface activity of the foaming agent, and the effects of the silicone surfactant on the surface tension, foam properties, and wettability were studied systematically. The experimental results showed that the surface tension of the foaming agent decreased, and the foaming and wettability increased with the increase in silicone surfactant concentration. By the synergistic action of nanoparticles and surfactants, long-lasting and stable foam, fast coal dust deposition rate and low contact angle can be obtained. Among them, 0.8 wt%GT-248 was added to achieve the best surface activity, foaming ability and wettability. These fundamental results might guide the application of silicone surfactants combined with nanoparticle-hydrocarbon surfactants in mine dust control.

Synthetic surfactant with a combined SP-B and SP-C analogue is efficient in rabbit models of adult and neonatal respiratory distress syndrome

Respiratory distress syndrome (RDS) in premature infants is caused by insufficient amounts of endogenous lung surfactant and is efficiently treated with replacement therapy using animal-derived surfactant preparations. On the other hand, adult/acute RDS (ARDS) occurs secondary to for example, sepsis, aspiration of gastric contents, and multitrauma and is caused by alveolar endothelial damage, leakage of plasma components into the airspaces and inhibition of surfactant activity. Instillation of surfactant preparations in ARDS has so far resulted in very limited treatment effects, partly due to inactivation of the delivered surfactants in the airspace. Here, we develop a combined surfactant protein B (SP-B) and SP-C peptide analogue (Combo) that can be efficiently expressed and purified from Escherichia coli without any solubility or purification tag. NMR spectroscopy shows that Combo peptide forms α-helices both in organic solvents and in lipid micelles, which coincide with the helical regions described for the isolated SP-B and SP-C parts. Artificial Combo surfactant composed of synthetic dipalmitoylphosphatidylcholine:palmitoyloleoylphosphatidylglycerol, 1:1, mixed with 3 weights % relative to total phospholipids of Combo peptide efficiently improves tidal volumes and lung gas volumes at end-expiration in a premature rabbit fetus model of RDS. Combo surfactant also improves oxygenation and respiratory parameters and lowers cytokine release in an acid instillation-induced ARDS adult rabbit model. Combo surfactant is markedly more resistant to inhibition by albumin and fibrinogen than a natural-derived surfactant in clinical use for the treatment of RDS. These features of Combo surfactant make it attractive for the development of novel therapies against human ARDS.

Perspectives on Corrosion Inhibition Features of Novel Synthesized Gemini-Fluorinated Cationic Surfactants Bearing Varied Spacers for Acid Pickling of X60-Steel: Practical, and In Silico Calculations.

Through our present study, three novel Gemini-fluorinated cationic surfactants bearing different spacers (FSG6-2, FSG6-4, and FSG6-6) were synthesized, and their structures were explained via different spectroscopic instruments such as 1H, 13C, and 19F NMR spectra. The surface activity of the as-prepared surfactants was examined. The inhibiting influence of FSG6 molecules on the X60 steel corrosion in the pickling solution (HCl) was examined by diverse methods comprising electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and X-ray photoelectron spectroscopy (XPS) experimentations, and computational calculations. The inhibition effectiveness of FSG6 surfactants followed the order of 93.37% (FSG6-2) < 96.74% (FSG6-4) < 98.37% (FSG6-6) at 2.0 × 10-4 M. The FSG6 surfactants function as mixed-type inhibitors, according to PDP investigations. The H2O molecules that adsorbed on the steel interface were substituted with surfactant molecules, and the surfactant's inhibitory activity is likely caused by the improvement in an adsorptive layer on the steel substrate, as specified by the EIS results. The Langmuir isotherm describes the absorption of FSG6 molecules on the metal surface. The XPS investigations validate the steel interface's extremely protective nature. The mechanism of interaction between FSG6 molecules with an X60-steel employing the DFT calculations and MC simulations methods was also examined and discussed.

Propionic acid-based additive with surfactant action on the feeding value of rehydrated corn grain silage for dairy cows performance

Eighteen Holstein cows with 218 ± 106 days in milk (mean ± SD) and average daily milk yield of 22 ± 7.6 kg (mean ± SD) were assigned to six 3 × 3 Latin squares to evaluate the effects of using a propionic acid-based additive with surfactant action (Mycoflake™; Kemin South America, Indaiatuba, SP, Brazil) at the ensiling of rehydrated corn grain on its nutritional value and animal performance. Dry ground corn grain (998 μm) was rehydrated to reach 400 g/kg fresh matter of moisture, with or without the additive, and ensiled in 200-L plastic drums. Treatments were prepared as follows: rehydrated corn grain silage (RCGS) stored for 30 d as a negative control (30CON), RCGS stored for 60 d as a positive control (60CON) and RCGS treated with Mycoflake™ at 2 L/t and stored for 30 d (30MYC). The animals were offered a total mixed ration containing 399 g/kg whole-plant corn silage, 98 g/kg Tifton haylage, 207 g/kg RCGS (according to treatment), 98 g/kg citrus pulp, 173 g/kg soybean meal and 25 g/kg mineral-vitamin mix in total diet dry matter (DM). Ruminal DM disappearance (DMD) of RCGS was evaluated in situ using two canulated Holstein cows after 12, 24 and 48 h of incubation. Total tract apparent digestibility (TTAD) of nutrients was determined using the indigestible neutral detergent fiber content as a marker measured after 288 h of incubation in a canulated Holstein cow. Although no change in soluble protein content was observed for the 30MYC silage, its NH3-N content was greater than 30CON in both DM (P = 0.01) and total N (P = 0.02) basis, and did not differ from 60CON. The proportion of NH3-N in soluble N of 30MYC was the highest compared to both 30CON (P = 0.02) and 60CON (P < 0.01). The 30MYC RCGS presented lower geometric mean particle size and greater surface area than both 30CON (P < 0.01) and 60CON (P < 0.01). Although the pH of 30MYC RCGS did not differ from 30CON and 60CON, its lactic acid content (11.9 g/kg DM) was greater than both 30CON (9.28 g/kg DM; P = 0.05) and 60CON (8.10 g/kg DM; P = 0.01). No changes in ruminal DMD were observed for 30MYC RCGS against 30CON. There were no changes on dairy cows performance fed the 30MYC RCGS against 30CON. Cows fed 30MYC RCGS presented a different pattern of sorting behavior against 30CON and 60CON, resulting in lower intake of physically effective fiber than both 30CON (P = 0.01) and 60CON (P = 0.02), although no effect on ruminating and chewing activities was observed. No effect on TTAD of nutrients was observed for cows fed 30MYC RCGS against 30CON. Mycoflake™ hampered the formation of aggregates in RCGS, and did not enhance proteolysis. Despite changes in sorting behavior, the additive did not affect performance of dairy cows.

Phenylalanine and Tryptophan-Based Surfactants as New Antibacterial Agents: Characterization, Self-Aggregation Properties, and DPPC/Surfactants Vesicles Formulation.

Cationic surfactants based on phenylalanine (CnPC3NH3Cl) and tryptophan (CnTC3NH3Cl) were synthesized using renewable raw materials as starting compounds and a green synthetic procedure. The synthesis, acid-base equilibrium, aggregation properties, and antibacterial activity were investigated. Conductivity and fluorescence were used to establish critical micelle concentrations. Micellization of CnPC3NH3Cl and CnTC3NH3Cl occurred in the ranges of 0.42-16.2 mM and 0.29-4.6 mM, respectively. Since those surfactants have some acidic character, the apparent pKa was determined through titrations, observing increasing acidity with increasing chain length and being slightly more acidic with the phenylalanine than the tryptophan derivatives. Both families showed promising antibacterial efficacy against eight different bacterial strains. Molecular docking studies against the enzyme peptidoglycan glycosyltransferase (PDB ID:2OQO) were used to investigate the potential binding mechanism of target surfactant molecules. According to small angle X-ray scattering (SAXS) results, the surfactants incorporate into DPPC (Dipalmitoyl Phosphatidyl Choline) bilayers without strong perturbation up to high surfactant concentration. Some of the C12TC3NH3Cl/DPPC formulations (40%/60% and 20%/80% molar ratios) exhibited good antibacterial activity, while the others were not effective against the tested bacteria. The strong affinity between DPPC and surfactant molecules, as determined by the DFT (density functional theory) method, could be one of the reasons for the loss of antibacterial activity of these cationic surfactants when they are incorporated in vesicles.