Effect of cetrimonium carrier micelles on bacterial membranes and extracellular DNA, an in silico study.

Microorganisms do not live as dispersed single cells but rather they form aggregates with extracellular polymeric substances at interfaces. Biofilms are considered efficient life forms because they shield bacteria from biocides and collect dilute nutrients. This is a big concern in industry since the microorganisms can colonize a wide range of surfaces, accelerating material deterioration, colonizing medical devices, contaminating ultrapure drinking water, increasing energy costs and creating focus of infection. Conventional biocides that target a specific component of the bacteria are not effective in the presence of biofilms. Efficient biofilm inhibitors are based on a multitarget approach interacting with the bacteria and the biofilm matrix. Their rationale design requires a thorough understanding of inhibitory mechanisms that are still largely lacking today. Herein we uncover via molecular modelling the inhibition mechanism of cetrimonium 4-OH cinnamate (CTA-4OHcinn). Simulations show that CTA-4OH micelles can disrupt symmetric and asymmetric bilayers, representative of inner and outer bacterial membranes, following three stages: adsorption, assimilation, and defect formation. The main driving force for micellar attack is electrostatic interactions. In addition to disrupting the bilayers, the micelles work as carriers facilitating the trapping of 4OH cinnamate anions within the bilayer upper leaflet and overcoming electrostatic repulsion. The micelles also interact with extracellular DNA (e-DNA), which is one of the main components of biofilms. It is observed that CTA-4OHcinn forms spherical micelles on the DNA backbone; which hinders their ability to pack. This is demonstrated by modelling the DNA along the hbb histone-like protein, showing that in the presence of CTA-4OHcinn, DNA does not pack properly around hbb. The abilities of CTA-4OHcinn to cause cell death through membrane disruption and to disperse a mature, multi-species biofilm are also confirmed experimentally.

Antibacterial and antifungal action of CTAB-containing silica nanoparticles against human pathogens.

New antibiotic agents are urgently needed worldwide to combat the increasing tolerance and resistance of pathogenic fungi and bacteria to current antimicrobials. Here, we looked at the antibacterial and antifungal effects of minor quantities of cetyltrimethylammonium bromide (CTAB), ca. 93.8 mg g-1, on silica nanoparticles (MPSi-CTAB). Our results show that MPSi-CTAB exhibits antimicrobial activity against Methicillin-resistant Staphylococcus aureus strain (S. aureus ATCC 700698) with MIC and MBC of 0.625 mg mL-1 and 1.25 mg mL-1, respectively. Additionally, for Staphylococcus epidermidis ATCC 35984, MPSi-CTAB reduces MIC and MBC by 99.99% of viable cells on the biofilm. Furthermore, when combined with ampicillin or tetracycline, MPSi-CTAB exhibits reduced MIC values by 32- and 16-folds, respectively. MPSi-CTAB also exhibited in vitro antifungal activity against reference strains of Candida, with MIC values ranging from 0.0625 to 0.5 mg mL-1. This nanomaterial has low cytotoxicity in human fibroblasts, where over 80% of cells remained viable at 0.31 mg mL-1 of MPSi-CTAB. Finally, we developed a gel formulation of MPSi-CTAB, which inhibited in vitro the growth of Staphylococcus and Candida strains. Overall, these results support the efficacy of MPSi-CTAB with potential application in the treatment and/or prevention of infections caused by methicillin-resistant Staphylococcus and/or Candida species.

Effects of Silver Nanoparticles on Physiological and Proteomic Responses of Tobacco (Nicotiana tabacum) Seedlings Are Coating-Dependent.

The harmful effects of silver nanoparticles (AgNPs) have been confirmed in many organisms, but the mechanism of their toxicity is not yet fully understood. In biological systems, AgNPs tend to aggregate and dissolve, so they are often stabilized by coatings that influence their physico-chemical properties. In this study, the effects of AgNPs with different coatings [polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB)] on oxidative stress appearance and proteome changes in tobacco (Nicotiana tabacum) seedlings have been examined. To discriminate between the nanoparticulate Ag form from the ionic one, the treatments with AgNO3, a source of Ag+ ions, were also included. Ag uptake and accumulation were found to be similarly effective upon exposure to all treatment types, although positively charged AgNP-CTAB showed less stability and a generally stronger impact on the investigated parameters in comparison with more stable and negatively charged AgNP-PVP and ionic silver (AgNO3). Both AgNP treatments induced reactive oxygen species (ROS) formation and increased the expression of proteins involved in antioxidant defense, confirming oxidative stress as an important mechanism of AgNP phytotoxicity. However, the mechanism of seedling responses differed depending on the type of AgNP used. The highest AgNP-CTAB concentration and CTAB coating resulted in increased H2O2 content and significant damage to lipids, proteins and DNA molecules, as well as a strong activation of antioxidant enzymes, especially CAT and APX. On the other hand, AgNP-PVP and AgNO3 treatments induced the nonenzymatic antioxidants by significantly increasing the proline and GSH content. Exposure to AgNP-CTAB also resulted in more noticeable changes in the expression of proteins belonging to the defense and stress response, carbohydrate and energy metabolism and storage protein categories in comparison to AgNP-PVP and AgNO3. Cysteine addition significantly reduced the effects of AgNP-PVP and AgNO3 for the majority of investigated parameters, indicating that AgNP-PVP toxicity mostly derives from released Ag+ ions. AgNP-CTAB effects, however, were not alleviated by cysteine addition, suggesting that their toxicity derives from the intrinsic properties of the nanoparticles and the coating itself.

Fungicidal and antibiofilm activities of gold nanoparticles on Candida tropicalis.

Aim: To investigate the antifungal activity of two different functionalized gold nanoparticles (AuNP), those stabilized with cetyltrimethylammonium bromide and those conjugated with cysteine, and their effects on the architecture of Candida tropicalis biofilms. Materials & methods: Biofilms were studied by crystal violet binding assay and scanning electron microscopy. We investigated the effects of AuNPs on reactive oxygen species, reactive nitrogen intermediates and enzymatic and nonenzymatic antioxidant defenses. Results/Conclusion: The fungicidal activity and cellular stress of both AuNPs affected biofilm growth through accumulation of reactive oxygen species and reactive nitrogen intermediates. However, cetyltrimethylammonium bromide-stabilized AuNPs revealed a higher redox imbalance. We correlated, for the first time, AuNP effects with the redox imbalance and alterations in the architecture of C. tropicalis biofilms.

Biofilms are at least 100­1000-times more resistant to the effects of antimicrobial agents compared with planktonic cells, and nanoparticles have emerged to provide new approaches to improve the safety and efficacy of antimicrobial therapy. The aim of this work was to investigate the antifungal activity with two different functionalized gold nanoparticles. A significant reduction of Candida tropicalis biofilms with alterations in surface topography and architecture was observed, and the oxidative and nitrosative stress affected the biofilms. To the best of our knowledge, this is the first study that attempts to correlate the antibiofilm effects of gold nanoparticles on the redox imbalance against biofilms. These compounds could be an alternative to fungal biofilms infections treatments, applied specifically in biological and medical fields.

Promising Anti-Biofilm Agents and Phagocytes Enhancers for the Treatment of Candida albicans Biofilm-Associated Infections.

Little is known about the interactions among phagocytes and antifungal agents and the antifungal immunomodulatory activities on Candida species biofilms. Here, inhibition of C. albicans biofilms and the interactions among biofilms and phagocytes alone or in combination with essential oils, biological, and chemical agents, or fluconazole were investigated. Biofilm formation by a panel of 28 C. albicans clinical isolates from hospitalized patients, birds, and cattle was tested. The anti-biofilm activities of cinnamon and clove oils, sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and Enterococcus faecalis cell-free supernatant (CFS) in comparison with fluconazole were investigated using crystal violet and XTT reduction assays, expression of hypha-specific and hyphal regulator genes, and scanning electron microscopy (SEM) analysis. Of the tested C. albicans isolates, 15 of 28 (53.6%) were biofilm producers. Cinnamon followed by E. faecalis-CFS, SDS, and CTAB was the most effective inhibitors of planktonic C. albicans and biofilms. Fluconazole was an ineffective inhibitor of C. albicans biofilms. Sessile minimal inhibitory concentration (SMIC50) of cinnamon, SDS, CTAB, and E. faecalis-CFS downregulated the hypha-specific and regulator genes, albeit to various extents, when compared with untreated biofilms (P < 0.001). SEM analysis revealed disruption and deformity of three-dimensional structures in cinnamon oil-treated biofilms. C. albicans sessile cells within biofilm were less susceptible to phagocytosis than planktonic cells. The additive effects of phagocytes and the tested antifungals enabled phagocytes to engulf C. albicans cells rapidly in cinnamon, E. faecalis-CFS, or SDS-treated biofilms. No differences in anti-Candida or anti-biofilm eradication activities were detected among the tested isolates. Our findings reinforce the substantial anti-biofilm activity of cinnamon oil, SDS, and E. faecalis-CFS and provide new avenues for the development of novel anti-biofilm immunotherapies or antifungals that could be used prior to or during the management of cases with biofilm-associated infections.

Effect of cetyltrimethylammonium chloride on various Escherichia coli strains and their inactivation kinetics by ozone and monochloramine.

Cethyltrimethylammonium chloride (CTMA) is one of the most used quaternary ammonium compounds (QACs) in consumer products. CTMA and other QACs are only partially eliminated in municipal wastewater treatment and they can interact with bacteria in biological processes. Currently, there is only limited information on the antimicrobial efficiency of CTMA in matrices other than standard growth media and if and how CTMA influences conventional chemical disinfection. The results obtained in this study showed that the susceptibility of E. coli to CTMA was significantly enhanced in phosphate-buffered saline, lake water and wastewater compared to broth. In broth, a minimum inhibitory concentration (MIC) of CTMA of 20 mgL-1 was observed for E. coli, whereas a 4-log inactivation occurred for CTMA concentrations of about 4 mgL-1 in buffered ultra-purified water, a lake water and wastewater effluent. The impacts of the pre-exposure and the presence of CTMA on inactivation by ozone and monochloramine were tested with three different E. coli strains: AG100 with the efflux pump acrAB intact, AG100A with it deleted and AG100tet with it overexpressed. Pre-exposure of E. coli AG100 to CTMA led to an increased susceptibility for ozone with second-order inactivation rate constants (∼ 106 M-1s-1) increasing by a factor of about 1.5. An opposite trend was observed for monochloramine with second-order inactivation rate constants (∼ 103 M-1s-1) decreasing by a factor of about 2. For E. coli AG100tet, the second-order inactivation rate constant decreased by a factor of almost 2 and increased by a factor of about 1.5 for ozone and monochloramine, respectively, relative to the strain AG100. The simultaneous presence of CTMA and ozone enhanced the second-order inactivation rate constants for CTMA concentrations of 2.5 mgL-1 by a factor of about 3. For monochloramine also an enhancement of the inactivation was observed, which was at least additive but might also be synergistic. Enhancement by factors from about 2 to 4.5 were observed for CTMA concentrations > 2.5 mgL-1.

An optimized method to obtain high-quality RNA from different tissues in Lilium davidii var. unicolor.

The high quality, yield and purity total RNA samples are essential for molecular experiments. However, harvesting high quality RNA in Lilium davidii var. unicolor is a great challenge due to its polysaccharides, polyphenols and other secondary metabolites. In this study, different RNA extraction methods, namely TRIzol method, the modified TRIzol method, Kit method and cetyltrimethylammonium bromide (CTAB) method were employed to obtain total RNA from different tissues in L. davidii var. unicolor. A Nano drop spectrophotometer and 1% agarose gel electrophoresis were used to detect the RNA quality and integrity. Compared with TRIzol, Kit and CTAB methods, the modified TRIzol method obtained higher RNA concentrations from different tissues and the A260/A280 ratios of RNA samples were ranged from 1.97 to 2.27. Thus, the modified TRIzol method was shown to be the most effective RNA extraction protocol in acquiring RNA with high concentrations. Furthermore, the RNA samples isolated by the modified TRIzol and Kit methods were intact, whereas different degrees of degradation happened within RNA samples isolated by the TRIzol and CTAB methods. In addition, the modified TRIzol method could also isolate high-quality RNA from other edible lily bulbs. Taken together, the modified TRIzol method is an efficient method for total RNA isolation from L. davidii var. unicolor.

Alteration of Cell Membrane Permeability by Cetyltrimethylammonium Chloride Induces Cell Death in Clinically Important Candida Species.

The increased incidence of healthcare-related Candida infection has necessitated the use of effective disinfectants/antiseptics in healthcare settings as a preventive measure to decontaminate the hospital environment and stop the persistent colonization of the offending pathogens. Quanternary ammonium surfactants (QASs), with their promising antimicrobial efficacy, are considered as intriguing and appealing candidates for disinfectants. From this perspective, the present study investigated the antifungal efficacy and action mechanism of the QAS cetyltrimethylammonium chloride (CTAC) against three clinically important Candida species: C. albicans, C. tropicalis, and C. glabrata. CTAC exhibited phenomenal antifungal activity against all tested Candida spp., with minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) between 2 and 8 µg/mL. The time−kill kinetics of CTAC (at 2XMIC) demonstrated that an exposure time of 2 h was required to kill 99.9% of the inoculums in all tested strains. An important observation was that CTAC treatment did not influence intracellular reactive oxygen species (ROS), signifying that its phenomenal anticandidal efficacy was not mediated via oxidative stress. In addition, sorbitol supplementation increased CTAC's MIC values against all tested Candida strains by three times (8−32 µg/mL), indicating that CTAC's possible antifungal activity involves fungus cell membrane destruction. Interestingly, the increased fluorescence intensity of CTAC-treated cells in both propidium iodide (PI) and DAPI staining assays indicated the impairment of cell plasma membrane and nuclear membrane integrity by CTAC, respectively. Additionally, CTAC at MIC and 2XMIC was sufficient (>80%) to disrupt the mature biofilms of all tested spp., and it inhibited the yeast-to-hyphae transition at sub-MIC in C. albicans. Finally, the non-hemolytic activity of CTAC (upto 32 µg/mL) in human blood cells and HBECs signified its non-toxic nature at the investigated concentrations. Furthermore, thymol and citral, two phytocompounds, together with CTAC, showed synergistic fungicidal effectiveness against C. albicans planktonic cells. Altogether, the data of the present study appreciably broaden our understanding of the antifungal action mechanism of CTAC and support its future translation as a potential disinfectant against Candida-associated healthcare infections.

Cetyltrimethylammonium Bromide Disrupts Mesenchymal Characteristics of Human Tongue Squamous Cell Carcinoma SCC4 Cells Through Modulating Canonical TGF-ß/Smad/miR-181b/TIMP3 Signaling Pathway.

BACKGROUND/AIM: This study investigated the anti-metastatic effects of cetyltrimethylammonium bromide (CTAB) on tongue squamous cell carcinoma (TSCC) SCC4 cells. MATERIALS AND METHODS: Cell morphology, viability, cell cycle distribution, adhesion, migration, invasion and the expression levels of associated proteins were examined using microscopy, WST-1, wound-healing, Boyden chamber assays, and western blotting, respectively. RESULTS: CTAB significantly affected SCC4 cell morphology from spindle-shaped to cobblestone-shaped and resulted in loss of adherence. CTAB significantly inhibited cell adhesion, migration, and invasion of SCC4 cells, independent of cell viability. CTAB reduced expression of matrix metalloproteinases (MMPs) such as MMP3, MMP7, and MMP14 in a concentration-dependent manner, while it increased expression of tissue inhibitors of metalloproteinase 3 (TIMP3). In addition, CTAB reduced the phosphorylation of mothers against decapentaplegic homolog 2/3 (Smad2/3) proteins, which mediated CTAB-inhibited migration and invasion in SCC4 cells. These effects were reversed by TGF-ß1. CONCLUSION: CTAB attenuates the mesenchymal characteristics through upregulation of TIMP3 by inhibiting the canonical TGF-ß/Smad/miR-181b/TIMP3 signaling involved in extracellular matrix remodeling in SCC4 cells and might be a promising anti-metastatic therapeutic agent for TSCC.

(De)stabilization of Alpha-Synuclein Fibrillary Aggregation by Charged and Uncharged Surfactants.

Parkinson's disease (PD) is the second most common neurodegenerative disorder. An important hallmark of PD involves the pathological aggregation of proteins in structures known as Lewy bodies. The major component of these proteinaceous inclusions is alpha (α)-synuclein. In different conditions, α-synuclein can assume conformations rich in either α-helix or ß-sheets. The mechanisms of α-synuclein misfolding, aggregation, and fibrillation remain unknown, but it is thought that ß-sheet conformation of α-synuclein is responsible for its associated toxic mechanisms. To gain fundamental insights into the process of α-synuclein misfolding and aggregation, the secondary structure of this protein in the presence of charged and non-charged surfactant solutions was characterized. The selected surfactants were (anionic) sodium dodecyl sulphate (SDS), (cationic) cetyltrimethylammonium chloride (CTAC), and (uncharged) octyl ß-D-glucopyranoside (OG). The effect of surfactants in α-synuclein misfolding was assessed by ultra-structural analyses, in vitro aggregation assays, and secondary structure analyses. The α-synuclein aggregation in the presence of negatively charged SDS suggests that SDS-monomer complexes stimulate the aggregation process. A reduction in the electrostatic repulsion between N- and C-terminal and in the hydrophobic interactions between the NAC (non-amyloid beta component) region and the C-terminal seems to be important to undergo aggregation. Fourier transform infrared spectroscopy (FTIR) measurements show that ß-sheet structures comprise the assembly of the fibrils.

Cetyltrimethylammonium Bromide Attenuates the Mesenchymal Characteristics of Hypopharyngeal Squamous Cell Carcinoma Through Inhibiting the EGFR/PI3K/AKT Signaling Pathway.

BACKGROUND/AIM: Cetyltrimethylammonium bromide (CTAB), a quaternary ammonium surfactant, was shown to have antitumor effects in a cellular mode of head and neck squamous cell carcinoma (HNSCC), modulating apoptotic and cytotoxic processes. However, the mechanisms by which CTAB exerts its effects against the epithelial- mesenchymal transition in HNSCC remain poorly understood. In the present study, we investigated whether CTAB inhibits cellular mobility and invasiveness of hypopharyngeal squamous cell carcinoma (HPSCC) cells. MATERIALS AND METHODS: WST-1, cell-cycle phase distribution, and wound healing, as well as transwell assays were conducted. Changes in protein expression patterns and related signaling pathways involved in effects of CTAB on HPSCC cell lines were evaluated by western blotting. RESULTS: Treatment of human HPSCC cell lines with CTAB significantly altered their morphology from spindle-like to cobblestone-like by diminishing mesenchymal-like phenotypic characteristics. CTAB also hindered cell functional properties, including migration and invasion, independently of cell viability. In addition, western blot results demonstrated that treatment with CTAB reduced expression of mesenchymal markers. Further investigation showed that CTAB treatment suppressed the phosphorylation of extracellular-regulated kinase 1/2, mechanistic target of rapamycin kinase and AKT serine/threonine kinase 1. CTAB also repressed the expression and phosphorylation levels of epidermal growth factor receptor (EGFR) and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), and the partial restoration of mesenchymal phenotype by EGF addition confirmed that CTAB inhibited migration and invasion in HPSCC cells by blocking the EGFR signaling pathway. CONCLUSION: Our results suggest that CTAB is involved in the suppression of EGFR-mediated mesenchymal phenotype and the molecular mechanism by which CTAB obstructs HPSCC cell metastasis may represent a promising strategy for use in HPSCC treatment.

Air-ozonolysis activation of polyolefins versus use of laden finishing to form contact-active nonwoven materials.

Two synthetic approaches were explored for modification of the polyolefins polyethylene/polypropylene (PE/PP) to form contact-active nonwoven materials. In the first approach, polymer surfaces were activated by O2-free air-ozonolysis, and then the active agent (trimethoxysilyl) propyl-octadecyl-dimethyl-ammonium chloride (C18-TSA) was covalently bound. In the second approach, the active agent was directly conjugated to the commercial 'finishing' that was then applied to the polymer. The chemical, physical and microscopic properties of the modified polymers were comprehensively studied, and their active site density was quantified by fluorescein sodium salt-cetyltrimethylammonium chloride reaction. The antimicrobial activity of the prepared nonwovens against Bacillus subtilis (Gram-positive) and Salmonella enterica (Gram-negative), and their stability at various pHs and temperatures were examined. The two approaches conferred antimicrobial properties to the modified polymers and demonstrated stable linkage of C18-TSA. However, the performance of the nonwovens formed by the first approach was superior. The study suggests two feasible and safe pathways for the modification of polyolefins to form contact-active nonwoven materials that can be further applied in various fields, such as hygiene products, medical fabrics, sanitizing wipes, and more.

The inhibitory effect of CTAB on human osteosarcoma through the PI3K/AKT signaling pathway.

Osteosarcoma (OS) metastasis and recurrence and multidrug resistance are three major obstacles in the clinic. New highly effective and low toxicity drugs for osteosarcoma are needed. The antitumoral efficacy of cetrimonium bromide (CTAB), a quaternary ammonium compound, is gradually being investigated. The aim of the present study was to investigate the effects of CTAB on OS cells and the underlying mechanisms. CTAB inhibited the proliferation of osteosarcoma cells in a concentration­ and time­dependent manner, resulting in cell cycle arrest in G1 phase. CTAB also suppressed the migration and invasion of HOS and MG63 cells at a low concentration without inhibiting the growth of human osteoblasts. Moreover, CTAB promoted caspase­mediated apoptosis of osteosarcoma cells through the PI3K/AKT cascade, and this effect was accompanied by obvious mitochondrial toxicity. In vivo, CTAB inhibited OS proliferation without inducing organ toxicity. In conclusion, this study reveals that CTAB has an inhibitory effect on OS by suppressing proliferation and metastasis and inducing apoptosis through the PI3K/AKT signaling pathway and identifies CTAB as a potential therapeutic drug.

Citrate-Stabilized Gold Nanorods-Directed Osteogenic Differentiation of Multiple Cells.

OBJECTIVE: Gold nanorods (AuNRs) show great potential for versatile biomedical applications, such as stem cell therapy and bone tissue engineering. However, as an indispensable shape-directing agent for the growth of AuNRs, cetyltrimethylammonium bromide (CTAB) is not optimal for biological studies because it forms a cytotoxic bilayer on the AuNR surface, which interferes with the interactions with biological cells. METHODS: Citrate-stabilized AuNRs with various aspect-ratios (Cit-NRI, Cit-NRII, and Cit-NRIII) were prepared by the combination of end-selective etching and poly(sodium 4-styrenesulfonate)-assisted ligand exchange method. Their effects on osteogenic differentiation of the pre-osteoblastic cell line (MC3T3-E1), rat bone marrow mesenchymal stem cells (rBMSCs), and human periodontal ligament progenitor cells (PDLPs) have been investigated. Potential signaling pathway of citrate-stabilized AuNRs-induced osteogenic effects was also investigated. RESULTS: The experimental results showed that citrate-stabilized AuNRs have superior biocompatibility and undergo aspect-ratio-dependent osteogenic differentiation via expression of osteogenic marker genes, alkaline phosphatase (ALP) activity and formation of mineralized nodule. Furthermore, Wnt/ß-catenin signaling pathway might provide a potential explanation for the citrate-stabilized AuNRs-mediated osteogenic differentiation. CONCLUSION: These findings revealed that citrate-stabilized AuNRs with great biocompatibility could regulate the osteogenic differentiation of multiple cell types through Wnt/ß-catenin signaling pathway, which promote innovative AuNRs in the field of tissue engineering and other biomedical applications.

Cetrimonium bromide promotes the clearance of lipids by activating the TFEB-mediated autophagosome-lysosome pathway in hepatic cells.

Autophagy plays a key role in the metabolism of macromolecules via the degradative abilities of the lysosome. Transcription factor EB (TFEB) regulates autophagosome biogenesis and lysosome function, and promoting TFEB activity has emerged as a potential strategy for the treatment of metabolic disorders. Herein, we report that cetrimonium bromide (CTAB; a quaternary ammonium compound) promotes autophagy and lysosomal biogenesis by inducing the nuclear translocation of TFEB in hepatic cells. Knockdown of TFEB mediated by short hairpin RNA inhibits CTAB-induced autophagy and lysosomal biogenesis. Mechanistically, CTAB treatment inhibits the Akt-mTORC1 signaling pathway. Moreover, CTAB treatment significantly increases lipid metabolism in both palmitate- and oleate-treated HepG2 cells, and this increase was attenuated by knockdown of TFEB. Collectively, our results indicate that CTAB activates the autophagosome-lysosome pathway via inducing the nuclear translocation of TFEB by inhibiting the mTORC1 signaling pathway. These results add to the collective understanding of TFEB function and provide new insights into CTAB-mediated lipid metabolism.

Removal of Salmonella Typhimurium Biofilm from Food Contact Surfaces Using Quercus infectoria Gall Extract in Combination with a Surfactant.

Quercus infectoria (nutgall) has been reported to possess antimicrobial activities against a wide range of pathogens. Nevertheless, the biofilm removal effect of nutgall extract has not been widely investigated. In this study, we therefore evaluated the effect of nutgall extract in combination with cetrimonium bromide (CTAB) against preformed biofilm of Salmonella Typhimurium on polypropylene (PP) and stainless steel (SS) coupons in comparison with other sanitizers. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of nutgall extract and surfactants (CTAB and sodium dodecyl sulfate; SDS) were assessed. CTAB showed a more efficient antimicrobial activity than SDS and was selected to use in combination with nutgall extract for removing biofilm. To determine the biofilm removal efficacy, the PP and SS coupons were individually submerged in 2x MBC of nutgall extract (256 mg/ml) + 2x MBC of CTAB (2.5 mg/ml), nutgall extract alone (256 mg/ml), CTAB alone (2.5 mg/ml), distilled water, and 100 ppm sodium hypochlorite for 5, 15, and 30 min. The remaining sessile cells in biofilm were determined. Overall, the greatest biofilm removal efficacy was observed with nutgall extract + CTAB; the biofilm removal efficacy of sanitizers tended to increase with the exposure time. The SEM analysis demonstrated that S. Typhimurium biofilm on PP and SS coupons after exposure to nutgall extract + CTAB for 30 min displayed morphological alterations with wrinkles. This study suggests nutgall extract + CTAB may be an alternative to commonly used sanitizers to remove biofilm from food contact surfaces in the food industry and household.

Surface Wiping Test to Study Biocide -Cinnamaldehyde Combination to Improve Efficiency in Surface Disinfection.

Disinfection is crucial to control and prevent microbial pathogens on surfaces. Nonetheless, disinfectants misuse in routine disinfection has increased the concern on their impact on bacterial resistance and cross-resistance. This work aims to develop a formulation for surface disinfection based on the combination of a natural product, cinnamaldehyde, and a widely used biocide, cetyltrimethylammonium bromide. The wiping method was based on the Wiperator test (ASTM E2967-15) and the efficacy evaluation of surface disinfection wipes test (EN 16615:2015). After formulation optimization, the wiping of a contaminated surface with 6.24 log10 colony-forming units (CFU) of Escherichia coli or 7.10 log10 CFU of Staphylococcus aureus led to a reduction of 4.35 log10 CFU and 4.27 log10 CFU when the wipe was impregnated with the formulation in comparison with 2.45 log10 CFU and 1.50 log10 CFU as a result of mechanical action only for E. coli and S. aureus, respectively. Furthermore, the formulation prevented the transfer of bacteria to clean surfaces. The work presented highlights the potential of a combinatorial approach of a classic biocide with a phytochemical for the development of disinfectant formulations, with the advantage of reducing the concentration of synthetic biocides, which reduces the potentially negative environmental and public health impacts from their routine use.

Cetyltrimethylammonium Bromide Suppresses the Migration and Invasion of Hepatic Mahlavu Cells by Modulating Fibroblast Growth Factor Signaling.

BACKGROUND/AIM: Liver cancer is the fourth leading cause of cancer-related mortality globally, of which hepatocellular carcinoma (HCC) accounts for 85-90% of total primary liver cancer. A drug shortage for HCC therapy triggered us to screen the small-molecule database with a high-throughput cellular screening system. Herein, we examined whether cetyltrimethylammonium bromide (CTAB) inhibits cellular mobility and invasiveness of Mahlavu HCC cells. MATERIALS AND METHODS: The effects of CTAB on cell viability were assessed using WST-1 assay, cell-cycle distribution using flow cytometric analysis, migration/invasion using woundhealing and transwell assays, and associated protein levels using western blotting. RESULTS: Treatment of Mahlavu cells with CTAB transformed its mesenchymal spindle-like morphology. In addition, CTAB exerted inhibitory effects on the migration and invasion of Mahlavu cells dose-dependently. CTAB also reduced the protein levels of matrix metalloproteinase-2 (MMP2), MMP9, RAC family small GTPase 1, SNAIL family transcriptional repressor 1 (SNAI1), SNAI2, TWIST family basic helix-loop-helix transcription factor 1 (TWIST1), vimentin, N-cadherin, phospho-fibroblast growth factor (FGF) receptor, phospho-phosphoinositide 3-kinase, phospho-v-Akt murine thymoma viral oncogene and phospho-signal transducer and activator of transcription 3 but increased the protein levels of tissue inhibitor of metalloproteinases-1/2 and E-cadherin. Rescue experiments proved that CTAB induced mesenchymal-epithelial transition in Mahlavu cells and this was significantly dose-dependently mitigated by basic FGF. CONCLUSION: CTAB suppressed the migration and invasion of Mahlavu cells through inhibition of the FGF signaling pathway. CTAB seems to be a potential agent for preventing metastasis of hepatic cancer.

Cetyltrimethylammonium Bromide Disrupts the Mesenchymal Characteristics of HA22T/VGH Cells Via Inactivation of c-Met/PI3K/Akt/mTOR Pathway.

BACKGROUND/AIM: Hepatocellular carcinoma (HCC) arises from hepatocytes, and is the most frequently occurring malignancy of primary liver cancer. In this study, we investigated the anti-metastatic effects of the quaternary ammonium compound, cetyltrimethylammonium bromide (CTAB), on HA22T/VGH HCC cells. MATERIALS AND METHODS: According to our preliminary data, the effect of CTAB on cell cycle distribution, migration, invasion and the associated protein levels was examined using flow cytometry, wound-healing migration, Matrigel transwell invasion assay and western blotting under sub-lethal concentrations. RESULTS: CTAB treatment of HA22T/VGH cells casued dose-dependent mesenchymal-epithelial transition (MET)-like changes and impaired migration and invasion capabilities. In addition, CTAB reduced the levels of metastasis-related proteins including c-Met, phosphoinositide 3-kinase (PI3K), Akt, mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase (p70S6K), Twist, N-cadherin, and Vimentin. Moreover, pretreatment with hepatocyte growth factor (HGF) rescued CTAB-mediated effects. CONCLUSION: CTAB exhibited potent anti-EMT and anti-metastatic activities through the inhibition of migration and invasion of HA22T/VGH cells. CTAB interrupted the mesenchymal characteristics of HA22T/VGH cells, which were significantly alleviated by HGF in a dose-dependent manner. CTAB has the potential to evolve as a therapeutic agent for HCC.

Comparison of two topical treatments on wound healing 7 days after disbudding of calves using thermocautery.

Aims To compare wound healing 7 days after cautery disbudding of dairy calves treated immediately after disbudding with a traditional antimicrobial spray (OXY) or with a topical anaesthetic gel containing cetrimide, adrenaline and two local anaesthetics, lignocaine and bupivacaine (TA). Method Eighty-one female dairy calves between 6-8 weeks of age were disbudded using a standard cautery disbudding protocol (sedation, cornual block, and analgesia), with complete removal of the horn bud. After disbudding, the wound on the right and left horn buds within each animal were randomly allocated to receive either OXY or TA. One week after disbudding, wounds were visually assessed for the presence of exudate, necrotic tissue, crust, or granulation tissue which were each assigned a grade from 1-3, where 1 = no evidence, 2 = moderate presence; and 3 = marked presence. Results At 7 days after disbudding, the prevalence of wounds with exudate or necrotic tissue was very low, and independent of treatment. The odds of a disbudding wound treated with TA being scored as having granulation tissue and was 5.2 (95% CI = 1.72-15.7) times that of a wound treated with OXY. Conversely, the odds of wounds treated with TA being scored as having crusts was 0.18 (95% CI = 0.06-0.57) that of a wound treated with OXY. No sign of infection was seen in any calves. Conclusion and clinical relevance The greater prevalence of granulation tissue and reduction in crusting in disbudding wounds treated with topical anaesthetic gel compared to those treated with the antimicrobial spray suggests that use of the topical anaesthetic gel may speed wound healing compared to using antimicrobial spray. This should be further tested in a larger study undertaken over a longer period.