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Fluoxetine (FLX), used in the clinic to treat depression, is a well-known cationic amphiphilic antidepressant. However, there is a lack of research on the effect of FLX on the surface behavior of lipid monolayers under different surface pressures. In this study, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/CHOL (DPPC/POPC/CHOL) monolayers were prepared via the Langmuir method, and FLX was added to these monolayers under various surface pressures. The effect of FLX on the surface behavior of DPPC/POPC/CHOL monolayers under various surface pressures was studied using a combination of surface pressure-area isotherms, compressibility modulus-surface pressure curves, and atomic force microscope (AFM). The results showed that the effect of FLX on the lipid monolayers was different under different surface pressures. The interaction between FLX and lipid molecules was weak under low surface pressures, and FLX could easily intercalate between the lipid molecules to inhibit monolayer phase transition. The interaction between FLX and lipid molecules was enhanced and FLX tended to self-aggregate to reduce the monolayer stability when the surface pressure was high. This study lays the foundation for further studies on the interaction between FLX and lipid monolayers. [ABSTRACT FROM AUTHOR]

This study investigates the effects of antidepressants fluoxetine, sertraline, and amitriptyline on the development of antibiotic resistance in clinical Acinetobacter baumannii isolates. The isolates were exposed to fluoxetine, sertraline, and amitriptyline for 30 days, respectively. The bacteria that developed resistance to gentamicin, imipenem, colistin, and ciprofloxacin were isolated and expression levels of some antibiotic-resistance genes were determined by quantitative reverse-transcriptase PCR. Before and after the exposure, minimum inhibitory concentration (MIC) values of the bacteria were determined by the microdilution method. The statistical analysis was performed using Student’s t test. A time-dependent increase was observed in the number of bacteria that developed resistance and increased the MIC value. After exposure to fluoxetine and sertraline, decreases were observed for efflux and outer membrane porin genes in isolates that developed colistin resistance, and increases were observed in isolates that developed ciprofloxacin resistance. These observations suggest that these antidepressants have similar effects on the development of resistance. While the exposure to fluoxetine did not result in the development of resistance to imipenem, it was observed after exposure to sertraline and amitriptyline, and a common decrease in ompA gene expression was determined in these isolates. To our knowledge, the comparative effects of selected antidepressants on the development of antibiotic resistance in A. baumannii are reported and presented in the literature here for the first time. [ABSTRACT FROM AUTHOR]

Various photocatalytic nanomaterials for environmental remediation have been promoted due to the pollution caused by different organic pollutants. In this study, Nb2O5 nanofibers were obtained by electrospinning technique, presenting controlled crystallinity and high specific surface area to improve the photoactivity response. The structural characterization indicated Nb2O5 nanofibers with orthorhombic phase formation. The photoluminescence measurements showed different energy levels contributing to the electronic transition events. The nanofibers with a bandgap up to 3.6 eV were applied to photocatalysis of dyes (rhodamine B (RhB) or methylene blue (MB)) and fluoxetine (FLX), listed as an emergent pollutant. In the optimized condition (pH = 9), the RhB and MB photocatalysis was 59% and 93% more efficient than photolysis due to ζ = − 50 mV ± 5 for EtOH_550 sample increased interaction with MB (cationic) compared to RhB unprotonated (pKa = 3.7). Therefore, FLX (pKa = 10.7) was selected due to protonated form at pH = 9 and showed 68% ± 1 adsorption in 30 min for EtOH_550. The FLX photocatalytic degradation under UV light irradiation was up to 17% higher than the photolytic degradation. The formation of hydroxyl radicals in the photocatalytic system (EtOH_550) was proven by the Coumarine probe assay, corroborating with the greater amount of α-[2-(methylamino)ethyl]benzylalcohol (MAEB), a by-product obtained after FLX oxidation. Additionally, the material achieved specific catalytic activity for the different organic compounds (RhB, MB, or FLX). Therefore, Nb2O5 nanofibers were efficient for degrading three different pollutants under UV light, proving a viable alternative for environmental remediation. [ABSTRACT FROM AUTHOR]

In this study, the interfacial behavior of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1,2-dipalmitoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (DPPC/DPPG) mixed monolayers with fluoxetine (FLX) in the subphase was investigated by a combination of the Langmuir-Blodgett technique and atomic force microscopy (AFM). It was found that DPPC/DPPG mixed monolayers showed different interfacial behaviors before and after addition of FLX in the subphase. The electrostatic interaction between FLX and lipids molecules destroys the homogeneity of the mixed monolayers and changes the arrangement of lipids molecules at the interface after addition of FLX in the subphase, thereby leading to an increase of compressibility and miscibility and a decrease in the stability of the mixed monolayers. The surface morphology of the mixed monolayers observed by AFM was different between without and with FLX in the subphase, indicating the penetration of FLX into the mixed monolayers. The present study has provided detailed information for further understanding the interactions of drugs with membrane lipids in other lipid monolayers. [ABSTRACT FROM AUTHOR]

The use of cork granules for cleaning up crude oil or oil derivative spills and further oil recovery appears as a promising option due to their unique properties, which allow a high oil sorption capacity, low water pickup and excellent reuse. The present work reports the effect of oil viscosity on cork sorption capacity by using five types of oils (lubricating oil, 5.7 goil gcork−1; heavy oil, 4.2 goil gcork−1; light oil, 3.0 goil gcork−1; biodiesel, 2.6 goil gcork−1; and diesel, 2.0 goil gcork−1). The cork sorption capacity for light petroleum was also evaluated as a function of temperature and sorbent particle size. Additionally, improvements on oil recovery from cork sorbents by a mechanical compression process have been achieved as a result of a design of experiments (DOE) using the response surface methodology. Such statistical technique provided remarkable results in terms of cork sorbent reusability, as the oil sorption capacity was preserved after 30 cycles of sorption-squeezing steps. The sorbed oils could be removed from the sorbent surface, collected simply by squeezing the cork granules and further reused. The best operational region yielded near 80% oil recovery, using a cork mass of 8.85 g (particle size of 2.0–4.0 mm) loaded with 43.5 mL of lubricating oil, at 5.4 bar, utilising two compressions with a duration of 2 min each. [ABSTRACT FROM AUTHOR]

Purpose: The inhibitors of the human isoform 5 of lactate dehydrogenase (hLDH5) have attracted growing interest as efficient anti-cancer agents. In the present paper, the interactions between an efficient hLDH5 inhibitor (N-hydroxyindole-2-carboxylic derivative) and lipid bilayers based on dipalmitoylphosphatidylcholine (DPPC) were investigated. Additionally, since interstitial acidification plays a key role in tumor pathogenesis and tumor drug therapy, the effect of acidic pH was assessed and correlated to DPPC/drug interaction.Methods: Four different techniques were used: differential scanning calorimetry, dynamic light scattering, UV-VIS second derivative spectrometry and attenuated total reflection Fourier transformed infrared spectroscopy.Results: All techniques concur in highlighting a structural change of lipid assembly, susceptible both to pH change and to the presence of the antitumor compound. Lipid vesicles appeared more compact at the lower pH, since the thermal pre-transition from the lamellar gel phase to the ripple gel phase was absent at pH 7.4 and the infrared analysis revealed a stronger acyl chain packing as well as a different hydration degree. Drug interaction was mainly detected in the lipid region including the ester linkages and the first portion of the acyl chains. Furthermore, a lower drug partitioning was recorded at pH 6.6.Conclusions: The investigated antitumor agent possesses a stable negative charge at the investigated pH values, thus the lower interaction at the acidic pH is mainly ascribable to an environmental effect on lipid assembly. Therefore, drug efficacy under tumor acid conditions may be hampered by the observed lipid membrane constraints, and suggest for the development of suitable prodrugs. [ABSTRACT FROM AUTHOR]