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Staphylococcus aureus is known to be a human pathogen and is often resistant to antibiotics, so there is a demand for new treatment alternatives that have the ability to reverse such resistance. The present study aimed to evaluate the antibacterial action and reversal of the efflux pump activity of the compounds Isopulegol (ISO) and its β-cyclodextrin inclusion complex (ISO/β-CD) in S. aureus strains carrying an efflux pump. (MsrA, TetK, NorA and MepA). The complex was obtained using the paste complexation method. The minimum inhibitory concentration (MIC) of ISO and ISO/β-CD was determined for the evaluation of antibacterial activity against multiresistant strains of S. aureus (RN4220, IS-58, 1199, 1199B and K2068) and the compounds showed a minimum inhibitory concentration (MIC) ≥ 1024 μg/mL. Modulation assays were performed using ISO and ISO/β-CD, which associated with antibiotics and Ethidium Bromide (EtBr) showed synergism and MIC reduction in some of the tested bacteria. Therefore, it can be concluded that the isolated compounds ISO and ISO/β-CD are effective in inhibiting the efflux pump mechanism against some of the tested strains; with modulation, only strains IS-58, SA 1199 and K2068 showed a MIC decrease effect, while all strains showed a reduction in MIC with ethidium bromide. [ABSTRACT FROM AUTHOR]

The excitation-dependent emission properties of carbon dots (Cdots) are extensively reported, but their red emission is often weak, limiting their wider application. Here we introduce ethidium bromide, as a functional precursor with red emission, to enhance the red emission for Cdots, with comparable intensity at a broad wavelength range to multi-emission Cdots (M-Cdots). We found that Cdots prepared with ethidium bromide/ethylenediamine exhibited strong blue and red emission at 440 and 615 nm, with optimal excitation at 360 and 470 nm as M-Cdots, respectively, but the Cdots from single ethidium bromide (EB-Cdots) possessed weak red emission. M-Cdots exhibited a broad absorption band at 478 nm, but a band blue-shifted to 425 nm was observed for EB-Cdots, while no absorption was observed at 478–425 nm for the Cdots prepared with citric acid and ethylenediamine. Thus, we proposed that C=O and C=N formed a π-conjugation structure as the absorption band at 478 nm for the red emission of M-Cdots, as also confirmed with the excitation at 470 nm. Moreover, the π-conjugation structure is fragile and sensitive to harsh conditions, so red emission was difficult to observe for the Cdots prepared with citric acid/ethylenediamine or single ethidium bromide. M-Cdots possess two centers for blue and red emission with different structures. The dual emission was therefore used for ratiometric sensing with dichromate (Cr2O72−) and formaldehyde (HCHO) as the targets using the intensity ratio of the emissions at 615 and 440 nm. Due to the comparable intensity at a broad wavelength range, we designed encryption codes with five excitations at 360, 400, 420, 450, and 470 nm as the inputs, and the emission colors were used for information decoding. Thus, we determined why red emission was difficult to realize for Cdots, and our results could motivate the design of red-emission Cdots for extensive applications. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the effects of time, temperature, and burial in a natural environment on the viability of chondrocytes in porcine femoral condyles using confocal laser scanning microscopy. Hind trotters from 10 pigs were buried or left unburied. Samples were collected daily and stained with a combination of vital dyes (calcein-AM and ethidium homodimer-1). The chondrocytes showed an intense staining corresponding to their vitality. In the first 3 days, viability decreased slowly and showed no statistical difference between buried and unburied samples. After the first 3 days, it decreased rapidly, with the viability of the buried samples being 66% on day 4, decreasing to 25% on day 8 and to 16% on day 10, while in the unburied samples it decreased to 43% on day 4, 13% on day 8 and 5% on day 10. Our results indicate a time, temperature, and burial dependent decrease in chondrocyte viability and suggest the use of chondrocyte viability as a marker for estimating PMI in both the natural environment and in animals, as well as its potential use in humans. [ABSTRACT FROM AUTHOR]

Ethidium Bromide (EtBr) serves as an interpolating agent utilized for its fluorescent properties in gel electrophoresis, aiding in the detection of various DNA fragments. However, its usage has been associated with DNA mutations, inhibition of mitochondrial protein synthesis and other alterations, particularly at high concentrations. Due to its remarkable stability in the environment and propensity to degrade into mutagenic compounds, especially when exposed to bleaching agents, there are significant concerns regarding its widespread use. Given the potential toxic and mutagenic effects of EtBr and the possibility of its entry into the food chain, it becomes crucial to monitor its concentration at emission sources across different ecosystems, including aquatic, terrestrial, and plant environments. Improper disposal of EtBr poses substantial risks, including the induction of mutations and cancer. Various disposal methods have been explored, such as phytoremediation and employing bacteria capable of degrading this chemical. Proper management of EtBr disposal is paramount to mitigate its harmful impact on the environment and living organisms. [ABSTRACT FROM AUTHOR]

The interaction of methylene blue (MB) and ethidium bromide (EB) intercalators with synthetic single-strand (ss) polynucleotides poly(rA) and poly(rU) and the double-strand (ds) poly(rA)–poly(rU) formed as a result of their hybridization was investigated in 0.04 mole solution in the range of phosphate/ligand ratios r = 0 ≤ r ≤ 10. The absorption spectra of complexes of the ligands with the polynucleotides were obtained, and adsorption isotherms in Scatchard coordinates were constructed on the basis of changes in the absorption spectra. It was found that MB interacts cooperatively with poly(rA) and also with ds-poly(rA)–poly(rU), while cooperation is not detected in the case of poly(rU). There is also no cooperation in the interaction of EB with ss- and ds-polynucleotides. The binding parameters for the interaction of these ligands with the polynucleotides (the association constants K and the number of bases n per binding site and also the cooperation factor) in the interaction of MS with poly(rA) and ds-poly(rA)- poly(rU) were determined from the adsorption isotherms. Both ligands were found to bind to polynucleotides by at least two methods, and MB here exhibits much higher affinity to poly(rA) and EB to ds-poly(rA)-poly(rU). [ABSTRACT FROM AUTHOR]

In this work, a novel chromatin-loaded chitosan polyvinyl alcohol composite was developed as a simple, efficient and environmentally friendly adsorbent for the efficient removal of ethidium bromide (EtBr). SEM images showed that the composites were characterized by dense porous and uniformly distributed morphology. The BET analysis showed the presence of mesopores and macropores in the composites. FTIR and XRD results showed that the chromatin was uniformly dispersed in the chitosan-polyvinyl alcohol carrier through hydrogen bonding. The fluorescence microscopy images showed the change of fluorescence effect before and after the adsorption of the material, which indicated that the chromatin was uniformly distributed in the composites and had a good adsorption effect. The optimal experimental conditions were T = 30℃, t = 120 min, pH = 7.4, m = 0.2 g when the composite with only 5% chromatin content had the ability to adsorb EtBr efficiently (minimum concentration 2 mg·L−1: adsorption rate 99%; maximum concentration 20 mg·L−1: adsorption rate 90%).The adsorption kinetics and thermodynamics showed that the EtBr adsorption kinetics of the composite conformed to the pseudo-second-order kinetic model (0.995 < R2 < 0.999) and the Freundlich isothermal model, and was a spontaneous process (ΔH < 0). This study on the immobilization of chromatin will provide a new way and reference for the application of chromatin in the treatment of EtBr pollutants. [ABSTRACT FROM AUTHOR]

Valencene and nootkatone are aromatic sesquiterpenes with known biological activities, such as antimicrobial, antioxidant, anti-inflammatory, and antitumor. Given the evidence that encapsulation into nanosystems, such as liposomes, could improve the properties of several compounds, the present study aimed to evaluate the activity of these sesquiterpenes in their isolated state or in liposomal formulations against strains of Staphylococcus aureus carrying efflux pumps. The broth microdilution method evaluated the antibiotic-enhancing activity associated with antibiotics and ethidium bromide (EtBr). The minimum inhibitory concentration was assessed in strains of S. aureus 1199B, IS-58, and RN4220, which carry the efflux proteins NorA, Tet(K), and MsrA. In tests with strain 1199B, valencene reduced the MIC of norfloxacin and EtBr by 50%, while the liposomal formulation of this compound did not show a significant effect. Regarding the strain IS-58, valencene, and its nanoformulation reduced norfloxacin MIC by 60.3% and 50%, respectively. In the non-liposomal form, the sesquiterpene reduced the MIC of EtBr by 90%. Against the RN4220 strain, valencene reduced the MIC of the antibiotic and EtBr by 99% and 93.7%, respectively. Nootkatone and its nanoformulation showed significant activity against the 1199B strain, reducing the EtBr MIC by 21.9%. Against the IS-58 strain, isolated nootkatone reduced the EtBr MIC by 20%. The results indicate that valencene and nootkatone potentiate the action of antibiotics and efflux inhibitors in strains carrying NorA, Tet(K), and MsrA proteins, which suggests that these sesquiterpenes act as efflux pump inhibitors in S. aureus. Therefore, further studies are needed to assess the impact of incorporation into liposomes on the activity of these compounds in vivo. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus can exhibit resistance to various antibiotics. Among its resistance mechanisms, the active efflux of antibiotics can be seen as relevant. This study aimed to evaluate the ability of resveratrol to modulate norfloxacin resistance in S. aureus. The antimicrobial activity of resveratrol was assessed using the broth microdilution method to determine the minimum inhibitory concentration (MIC). Then, the modulatory effect of resveratrol was evaluated using the MIC determination for the antibiotic or ethidium bromide in the presence and absence of resveratrol at a sub-MIC level. The MIC of norfloxacin against S. aureus SA1199B (NorA-overexpressing strain) decreased 16-fold when in the presence of resveratrol, with a similar behavior being observed for ethidium bromide. An evaluation of the ethidium bromide accumulation was also performed, showing that in the presence of resveratrol, the SA1199B strain had augmented fluorescence due to the accumulation of ethidium bromide. Altogether, the results suggested that resveratrol may act by inhibiting NorA. These in vitro data were supported by docking results, with interactions between resveratrol and the NorA efflux pump predicted to be favorable. Our findings demonstrated that resveratrol may modulate norfloxacin resistance through the inhibition of NorA, increasing the effectiveness of this antibiotic against S. aureus. [ABSTRACT FROM AUTHOR]

Brazilian flora are highly diverse and have great potential for research into new medicines of plant origin. Platonia insignis Mart. is a fruit tree from the Amazon region with several potential pharmacological applications already demonstrated. The present study aimed to investigate the protective effect of a mixture of the biflavones volkensiflavone and moreloflavone obtained from P. insignis flowers against the lethality induced by ethidium bromide in efflux pump overproducer strains of Staphylococcus aureus. Microdilution tests were performed to determine the minimum inhibitory concentration of ethidium bromide in the absence or presence of biflavones. The addition of biflavones to the growth medium increased the minimum inhibitory concentration of ethidium bromide against all strains tested, indicating that biflavones protected the bacterial cells against cell damage induced by this biocide agent. Comparative analysis of the infrared absorption spectra of each isolated compound, as well as of the associated compounds, demonstrated the complexation reaction, indicating that there was a preferential interaction between the H2N- groups of primary amines of ethidium bromide with the carbonyls of biflavones that formed imines -C=NH. Such complexation could reduce the amount of free ethidium bromide molecules available for DNA intercalation, resulting in the observed protective effect. These results suggest a possible technological application of the biflavones from P. insignis as protective agents against cell damage induced by ethidium bromide. [ABSTRACT FROM AUTHOR]

The bacterial species Staphylococcus aureus presents a variety of resistance mechanisms, among which the expression of β-lactamases and efflux pumps stand out for providing a significant degree of resistance to clinically relevant antibiotics. The 1,8-naphthyridines are nitrogen heterocycles with a broad spectrum of biological activities and, as such, are promising research targets. However, the potential roles of these compounds on bacterial resistance management remain to be better investigated. Therefore, the present study evaluated the antibacterial activity of 1,8-naphthyridine sulfonamides, addressing their ability to act as inhibitors of β-lactamases and efflux pump (QacA/B and QacC) against the strains SA-K4414 and SA-K4100 of S. aureus. All substances were prepared at an initial concentration of 1024 μg/mL, and their minimum inhibitory concentrations (MIC) were determined by the broth microdilution method. Subsequently, their effects on β-lactamase- and efflux pump-mediated antibiotic resistance was evaluated from the reduction of the MIC of ethidium bromide (EtBr) and β-lactam antibiotics, respectively. The 1,8-naphthyridines did not present direct antibacterial activity against the strains SA-K4414 and SA-K4100 of S. aureus. On the other hand, when associated with antibiotics against both strains, the compounds reduced the MIC of EtBr and β-lactam antibiotics, suggesting that they may act by inhibiting β-lactamases and efflux pumps such as QacC and QacA/B. However, further research is required to elucidate the molecular mechanisms underlying these observed effects. [ABSTRACT FROM AUTHOR]

Chalcones are present in a wide variety of plants, having in their structure two aromatic rings that are linked together by a chain composed of three carbon atoms with α, β‐unsaturated to carbonyl system. Bacteria have several drug resistance mechanisms, among them the efflux pump; this mechanism, when active, is able to expel different compounds from inside bacterial cells. Several efflux pumps have already been identified for Staphylococcus aureus bacteria, including MepA and NorA. Many chalcones have been isolated and identified with various activities, such as antimicrobial. In view of this, this article aimed to evaluate the antibiotic modifying effect of chalcone (E)‐1‐(2‐hydroxyphenyl)‐3‐(3‐nitrophenyl)prop‐2‐en‐1‐one against S. aureus carrier of NorA and MepA efflux pump. Regarding the antibiotic, there was a synergism when associated with ciprofloxacin in SA‐K2068 strain, showing this chalcone as an alternative to reverse the resistance to this medicine. The physicochemical properties calculated were fundamental in the description of the predicted pharmacokinetic properties. Despite the mutagenic risk caused by the metabolic activation of nitrochalcone, it is possible to notice a pharmacological principle in a longer half‐life for the performance of biological activities. The compound has a good bioavailability, as it is highly absorbed in the intestine and easily transported by plasma proteins, in addition to not presenting neurotoxic, hepatotoxic, and cardiotoxic damage. [ABSTRACT FROM AUTHOR]

Due to being low cost and eco-friendly, biological nanomaterial synthesis and development have made broad spectral progress. This study aimed to optimize the phytomediated synthesis of catalytically active, antibacterial palladium nanoparticles (PdNPs) for adsorption-based removal of ethidium bromide (EtBr) from an aqueous solution. Optimization of synthesis demonstrated that a precursor to extract ratio of 4:1, pH 3, and incubation at 80 °C for 60 min were the optimum conditions that led to the synthesis of negatively charged, highly stable, polycrystalline, spherical, and monodispersed PdNPs of 5–10 nm. When tested as catalysts, PdNPs successfully catalyzed Suzuki–Miyaura cross-coupling between aryl halides and arylboronic acids resulting in the synthesis of 4-acetylbiphenyl. Furthermore, the antibacterial activity test demonstrated that biogenic PdNPs were most effective and potent against Staphylococcus aureus and Proteus vulgaris followed by Escherichia coli, Bacillus subtilis, and Bacillus cereus. In addition, PdNPs were found as an excellent adsorbent for adsorption of EtBr from water as the adsorption reaction obeyed pseudo-second-order kinetics with a linear regression coefficient (R2 > 0.995). The adsorption reaction fitted well with the Freundlich and Temkin isotherm models, indicating multi-layer adsorption. Estimating thermodynamic parameters resulted in a positive value of ΔH0 and ΔG0, demonstrating adsorption was non-spontaneous and endothermic. [ABSTRACT FROM AUTHOR]

Ethidium bromide (EtBr) is a chemical agent commonly used to identify and visualize the bonding of DNA and RNA in molecular biology research. However, ethidium bromide itself is mutagenic and toxic. Ethidium bromide also has carcinogenic properties to human cells, teratogenic, and difficult to decompose. Therefore, a research for the treatment of EtBr waste is very important. There are several materials that can be used to reduce EtBr waste, but there is also needed a material which is cheap and widely available in the market. One of the methods to treat ethidium bromide waste is using activated charcoal. Activated charcoal has strong adsorption capacity due to its high surface area and porous structure. Another advantage of activated charcoal as an adsorbent is economical, effective, and environmentally friendly. In this study, EtBr waste was mixed with activated charcoal then homogenized for one hour. The mixing of EtBr waste (0.5 mg/mL concentration of EtBr) and activated charcoal was varied with a ratios weight by volume of 1:1, 1:2, and 2:1. The mixture of the solution was filtered using Whatmann filter paper No.1 to take the filtrate. The filtrate was further analyzed. The more activated charcoal was added, the more EtBr molecules were adsorbed. The pH in the filtration results for each variation was pH 7.0 - 8.0, dissolved oxygen with range 5.0 - 9.0 mg/L, biochemical oxygen demand (BOD) with range 25.06 - 78.2 mg/L, and chemical oxygen demand (COD) with range 302.56 - 310.98 mg/L. The concentration range was obtained as follows, for a 1:1 ratio of 0.045 - 0.060 mg/mL, for a 1:2 ratio of 0.028 - 0.032 mg/mL, while a 2:1 ratio of 0.081 - 0.090 mg/mL. In addition, the results showed that activated charcoal was able to bind Ethidium bromide due to bond interactions that occur between the EtBr molecule and activated charcoal. [ABSTRACT FROM AUTHOR]

Chemotherapy-inhibiting tumor cell evolution to drug-resistance is potentially suppressed by using a drug delivery vehicle (DDV) that has gating. Gating would be used to increase tumor-selectivity of delivery of DDV packaged drug. Tumor-selectivity increase would make possible increase in tumor-delivered drug dose, which would suppress opportunities to evolve drug resistance. Currently used DDVs do not have gating but gating is a natural feature of some bacteriophages (phages). Phage T4, which has recently been found highly persistent in murine blood, is a potential gated DDV. Thus, here, we proceed towards a T4-DDV by developing (1) improved procedure for generating high concentrations and amounts of phage T4, (2) elevated temperature-driven gate-opening and ethidium- and bleomycin-loading, and (3) purification of loaded T4 by rate zonal centrifugation. We test for loading by native agarose gel electrophoresis (AGE) with fluorescence detection. We observe loading in both phage T4 and T4 (tail-free) heads. The loaded particles have an openable, closed gate. Stored, mature T4 phages and phage heads do not release ethidium during at least a month at 4 °C and 6 days at 37 and 42 °C. Tumor-specific T4 phage delivery is projected via both the EPR effect and high T4 persistence. [ABSTRACT FROM AUTHOR]

With the recent stringent criteria for antibiotic susceptibility in probiotics, the presence of antibiotic resistance genes and plasmids associated with their transfer has become a limiting factor in the approval of probiotics. The need to remove genes related to antibiotic resistance and virulence through plasmid curing for the authorization of probiotics is increasing. In this study, we investigated the curing efficiency of ethidium bromide, acridine orange, and novobiocin at different concentrations and durations in five strains of plasmid-bearing lactic acid bacteria and examined the curing characteristics in each strain. Limosibacillus reuteri and Lacticaseibacillus paracasei exhibited curing efficiencies ranging from 5% to 44% following treatment with ethidium bromide (10-50 μg/ml) for 24-72 h, while Lactobacillus gasseri showed the highest efficiency at 14% following treatment with 10 μg/ml novobiocin for 24 h. Lactiplantibacillus plantarum , which harbors two or more plasmids, demonstrated curing efficiencies ranging from 1% to 8% after an additional 72-h treatment of partially cured strains with 10 μg/ml novobiocin. Plasmid curing in strains with larger plasmids exhibited lower efficiencies and required longer durations. In strains harboring two or more plasmids, a relatively low curing efficiency with a single treatment and a high frequency of false positives, wherein recovery occurred after curing, were observed. Although certain strains exhibited altered susceptibilities to specific antibiotics after curing, these outcomes could not be attributed to the loss of antibiotic resistance genes. Furthermore, the genomic data from the cured strains revealed minimal changes throughout the genome that did not lead to gene mutations.

Multiple sclerosis (MS) is a chronic neurodegenerative disease marked by oligodendrocyte loss, which results in central neuronal demyelination. AC/cAMP/CREB signaling dysregulation is involved in the progression of MS, including mitochondrial dysfunctions, reduction in nerve growth factors, neuronal inflammation, apoptosis, and white matter degeneration. Our previous research has shown that Forskolin (FSK), a naturally occurring direct adenylyl cyclase (AC)/cAMP/CREB activator, has neuroprotective potential to alleviate pathogenic factors linked with numerous neurological abnormalities. The current study intends to explore the neuroprotective potential of FSK at doses of 40 mg/kg and 60 mg/kg alone, as well as in combination with conventional medicines, such as Fingolimod (FNG), Donepezil (DON), Memantine (MEM), and Simvastatin (SIM) in EB-induced demyelinated experimental MS rats. Adult Wistar rats were divided into nine groups, and EB was infused stereotaxically in the rat brain's intracerebropeduncle (ICP) area. Chronic gliotoxin EB treatment results in demyelination as well as motor and cognitive dysfunctions. FSK, combined with standard medications, improves behavioral dysfunctions, such as neuromuscular and motor deficits and memory and cognitive abnormalities. Following pharmacological treatments improved remyelination by enhancing myelin basic protein and increasing AC, cAMP, and CREB levels in brain homogenates. Furthermore, FSK therapy restored brain mitochondrial-ETC complex enzymes and neurotransmitter levels while decreasing inflammatory cytokines and oxidative stress markers. The Luxol fast blue (LFB) stain results further indicate FSK's neuroprotective potential in preventing oligodendrocyte death. Therefore, the results of these studies contribute to a better understanding of the possible role that natural phytochemicals FSK could have in preventing motor neuron diseases, such as multiple sclerosis. [ABSTRACT FROM AUTHOR]

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DNA strand displacement is a technique to exchange one strand of a double stranded DNA by another strand (invader). It is an isothermal, enzyme free method driven by single stranded overhangs (toeholds) and is employed in DNA amplification, mismatch detection and nanotechnology. We discovered that anomeric (α/β) DNA can be used for heterochiral strand displacement. Homochiral DNA in β‐D configuration was transformed to heterochiral DNA in α‐D/β‐D configuration and further to homochiral DNA with both strands in α‐D configuration. Single stranded α‐D DNA acts as invader. Herein, new anomeric displacement systems with and without toeholds were designed. Due to their resistance against enzymatic degradation, the systems are applicable to living cells. The light‐up intercalator ethidium bromide is used as fluorescence sensor to follow the progress of displacement. Anomeric DNA displacement shows benefits over canonical DNA in view of toehold free displacement and simple detection by ethidium bromide. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is a severe immune-mediated neurological disease characterized by neuroinflammation, demyelination, and axonal degeneration in the central nervous system (CNS). This is frequently linked to motor abnormalities and cognitive impairments. The pathophysiological hallmarks of MS include inflammatory demyelination, axonal injury, white matter degeneration, and the development of CNS lesions that result in severe neuronal degeneration. Several studies suggested downregulation of nuclear factor erythroid-2-related factor-2 (Nrf2)/Heme oxygenase-1 (HO-1) signaling is a causative factor for MS pathogenesis. Acetyl-11-keto-β-boswellic acid (AKBA) is an active pentacyclictriterpenoid obtained from Boswellia serrata, possessing antioxidant and anti-inflammatory properties. The present study explores the protective potential of AKBA on behavioral, molecular, neurochemical, and gross pathological abnormalitiesandhistopathological alterations by H&E and LFB staining techniques in an experimental model of multiple sclerosis, emphasizing the increase inNrf2/HO-1 levels in the brain. Moreover, we also examine the effect of AKBA on the intensity of myelin basic protein (MBP) in CSF and rat brain homogenate. Specific apoptotic markers (Bcl-2, Bax, andcaspase-3) were also estimated in rat brain homogenate. Neuro behavioralabnormalities in rats were examined using an actophotometer, rotarod test, beam crossing task (BCT),and Morris water maze (MWM). AKBA 50 mg/kg and 100 mg/kg were given orally from day 8 to 35 to alleviate MS symptoms in the EB-injected rats. Furthermore, cellular, molecular, neurotransmitter, neuroinflammatory cytokine, and oxidative stress markers in rat whole brain homogenate, blood plasma, and cerebral spinal fluid were investigated. This study shows that AKBA upregulates the level of antioxidant proteins such as Nrf2 and HO-1 in the rat brain. AKBA restores altered neurochemical levels, potentially preventing gross pathological abnormalities during MS progression. [ABSTRACT FROM AUTHOR]

The efficient removal of Ethidium Bromide (EB), a toxic yet widely used chemical in biochemical industries and laboratories, is crucial to avoid its detrimental effect on human health, aquatic life, and the environment. One effective method is adsorption onto inert surfaces, but the choice of adsorbents is critical for the success of the removal protocols, primarily because of the limitations such as low adsorption capacity, high cost, limited availability, and a lack of understanding of the adsorption mechanism. In this work, Pyrophyllite Nanoclay (PNC), a naturally abundant aluminosilicate is explored as a promising adsorbent for EB. The adsorption process follows the Freundlich isotherm and displays pseudo-second-order kinetics. Under the optimized condition, PNC demonstrates nearly quantitative adsorption of EB and the maximum adsorption efficiency obtained from experiment was 6.53 mg/g (0.017 mmol/g) at room temperature under optimized condition. Through thermodynamic, kinetic analysis coupled with characterization techniques, the mechanism of adsorption is proposed. The adsorbent proves to be reusable, maintaining its performance over three cycles. The utility of the process is further validated and optimized using Response Surface Methodology (RSM). The present work focuses on the performance of PNC as adsorbent and elucidates distinctive surface adsorption mechanism (in comparison to other nanoclays), thus emphasizing the significance of structural, experimental, mechanistic and validation studies in choosing the right adsorbent for the removal toxic chemicals. [Display omitted] • Adsorption of Ethidium bromide on Pyrophyllite nanoclay (PNC) is investigated for the first time. • Kinetic and thermodynamic studies supported by characterization techniques reveal surface adsorption mechanism. • PNC is recyclable for at least three times. • Response Surface Methodology (RSM) optimization is conducted to validate the process. [ABSTRACT FROM AUTHOR]

In the present paper, an optimized method to extract common carp sperm DNA (csDNA) from common carp testis, the mechanism of ethidium bromide (EtBr) interaction with csDNA, as well as the removal of EtBr pollutant by csDNA was studied. The results showed that high salt extraction method was suitable for extracting csDNA. Under the optimum conditions, the yield of csDNA extraction was as high as 11.7%. In addition, the results of UV–vis spectra, fluorescence spectra, and observation with fluorescence microscope indicated that csDNA could be intercalated by EtBr to form a stable complex, which confirmed that csDNA could be applied in removing EtBr pollutant. Based on the csDNA intercalation, EtBr pollutant was removed by csDNA effectively, which was 94.13%. This work not only provides a smart method to extract high purity and quality csDNA from byproducts of common carp testis but also provides an easily available csDNA to remove EtBr from pollutants. [ABSTRACT FROM AUTHOR]

Bitter leaf (Vernonia amygdalina Del.) plant is a tree species that is highly cultivated in Nigeria for its nutritive and therapeutic values. This study aimed to determine the antioxidant and antigenotoxicity effects (in vitro) of 52 accessions of V. amygdalina collected from six geopolitical zones of Nigeria (North East, North West, North Central, South South, East and West) by evaluating the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO- ) scavenging antioxidant activities, flavonoid and phenolic contents as well as ethidium bromide-induced DNA (deoxyribonucleic acid) damage of bitter leaf. The results showed that accessions MN628016 (Oshimili South, Delta State) and MN628010 (Akoko Edo, Edo State), respectively had higher amounts of flavonoid (287.19 mg/g/FW) and phenolic (307.90 mg/g/FW) contents. The accessions MN627984 (Ikpoba Okha, Edo State) and MN627975 (Owerri, Imo State) had the highest nitric oxide (85.73%) and DPPH radical scavenging inhibitory effect (98.92%). The highest percentage fragmented DNA (45.05%), was observed in Allium cepa roots homogenised and mixed with ethidium bromide followed by the A. cepa roots homogenised and mixed with the leaf extract of V. amygdalina accession MN627977 (36.12%). However, V. amygdalina accessions MN628008 (457.62%, Warri North, Delta State) had the highest percentage increase of fragmented DNA followed by MN628024 (395.04%, Oshimili North, Delta State), MN628015 (345.54%; Aniocha North, Delta State) and MN627984 (342.04%; Ikpoba Okha, Edo State) while accession MN628010 (7.32%; Akoko Edo, Edo State) had the lowest. Accession MN628010 which possessed the highest amount of phenolic content had the lowest percentage increase of fragmented DNA and accession MN627984 which possessed the highest nitric oxide radical scavenging inhibitory effect was among the accessions with the highest percentage increase of fragmented DNA. The findings of this study suggest that the observed lowest percentage of fragmented DNA of A. cepa roots growth induced with the solution of ethidium bromide and treated with V. amygdalina accessions MN628010 extracts (antigenotoxic) could be as a result of the high antioxidant activities in the V. amygdalina accessions. In summary, the findings of this study showed that the 52 V. amygdalina accessions obtained from different locations of Nigeria will help to combat ethidium bromide induced genoxicities and any other genotoxicant that may lead to different complications in plant (A. cepa roots), as all the accessions possessed antioxidant and antigenotoxic properties, as such, possessed comparable amount of natural antioxidant activities and antigenotoxicity. [ABSTRACT FROM AUTHOR]

Ethidium bromide, which is commonly applied in molecular biological applications, is a mutagenic agent demanding proper treatment. In the present study, the magnetic fraction of fly ash, prepared from the ASTM class F material, was used as a catalyst for a heterogeneous Fenton process for degrading ethidium bromide in aqueous solution. The dosage of the catalyst, the initial pH of the solution, and the initial concentration of hydrogen peroxide significantly influenced the ethidium bromide removal rate. Under optimum conditions (2 mmol/L hydrogen peroxide and 100 g/L of the magnetic fraction of fly ash at pH 3), an ethidium bromide degradation efficiency of 98% was obtained within 4 h. The magnetic fraction of fly ash retained over 95% of its maximal ethidium bromide removal ability after three successive cycles. The heterogeneous Fenton process using the magnetic fraction of fly ash as a catalyst is robust and reusable. Therefore, the approach developed in this study may be an alternative cost-efficient heterogeneous Fenton catalyst for the removal of ethidium bromide from aqueous solution. [ABSTRACT FROM AUTHOR]

Lysophosphatidic acid (LPA) signaling via LPA receptors (LPA1 to LPA6) exhibits a variety of malignant properties in cancer cells. Intracellular ATP depletion leads to the development of necrosis and apoptosis. The present study aimed to evaluate the effects of LPA receptor-mediated signaling on the regulation of cancer cell functions associated with ATP reduction. Long-term ethidium bromide (EtBr) treated (MG63-EtBr) cells were established from osteosarcoma MG-63 cells. The intracellular ATP levels of MG63-EtBr cells were significantly lower than that of MG-63 cells. LPAR2, LPAR3, LPAR4 and LPAR6 gene expressions were elevated in MG63-EtBr cells. The cell motile and invasive activities of MG63-EtBr cells were markedly higher than those of MG-63 cells. The cell motile activity of MG-63 cells was increased by LPA4 and LPA6 knockdowns. In cell survival assay, cells were treated with cisplatin (CDDP) every 24 h for 3 days. The cell survival to CDDP of MG63-EtBr cells was lower than that of MG-63 cells. LPA2 knockdown decreased the cell survival to CDDP of MG-63 cells. The cell survival to CDDP of MG-63 cells was inhibited by (2 S)-OMPT (LPA3 agonist). Moreover, the cell survival to CDDP of MG-63 cells was enhanced by LPA4 and LPA6 knockdowns. These results indicate that LPA signaling via LPA receptors is involved in the regulation of cellular functions associated with ATP reduction in MG-63 cells treated with EtBr. [ABSTRACT FROM AUTHOR]

Ethidium bromide is extensively used in many biochemical laboratories. Due to its high toxicity, its removal from the wastewater before being disposed becoming an emerging issue. Swelling clay minerals, due to their inexpensive material cost, high efficiency, and vast reserves, have been evaluated for the removal of different types of contaminants. In this study, the removal of ethidium bromide, particularly its mechanism of removal was assessed, using Ca-montmorillonite (SAz-1) as a representative swelling clay minerals. The ethidium bromide removal could reach equilibrium within 1 h and a capacity of 1,276 mmol kg-1, same magnitude as the cation exchange capacity of SAz-1. The total amount of metal cations desorbed from SAz-1 to the amount of ethidium removed was linearly correlated with a slope of 0.7, suggesting cation exchange as the dominant mechanism. In addition, the less-than-unity desorption/adsorption ratio could be attributed to the removal of ethidium dimers bridged with bromide counterions. An increase of the basal spacing to 18.3 Å for SAz-1 after adsorption implied that intercalation of flat-lying ethidium dimers into the clay interlayer, which increased its thermal stability, and active participation of the amine groups of ethidium molecules in the adsorptive interaction was evidenced from Fourier transform infrared band shifts. The results suggested that Ca-montmorillonite is an excellent candidate for fast and effective removal of ethidium bromide from aqueous solution. As such, it could serve as an ideal packing material for kits to be manufactured and used for ethidium bromide removal in case of spill. [ABSTRACT FROM AUTHOR]

Ethidium bromide (EtBr) is widely used in most laboratories to detect nucleic acids in gel electrophoresis applications. It is a well-known carcinogenic and mutagenic agent, which can affect biotic components of the place in which it is disposed. Usually the gel-waste is either buried in the ground or incinerated, whereas the liquid waste is disposed of down the sink following the recommended methods of treatment. The recommended methods do not involve biological potential, but rather make use of chemicals, which may further deteriorate soil and water quality. The present study identifies and characterizes the EtBr-degrading bacterial isolates BR3 and BR4. A bibliographic review of the risk status of using these isolates for the treatment of lab waste in laboratory settings is also presented. BR3 was identified as Proteus terrae N5/687 (LN680103) and BR4 as Morganella morganii subsp. morganii ATCC 25830 (AJ301681) with 99.9% and 99.48% similarity, respectively, using an EzBioCloud microbial identifier. The literature revealed the bacterium Proteus terrae as a non-pathogenic and natural microflora of humans, but Morganella morganii as an opportunistic pathogen. These organisms belong to risk group II. Screening the sensitivity of these isolates to antibiotics revealed a sufficient number of antibiotics, which can be used to control them, if required. BR3 and BR4 exhibited resistance to individual antibiotics, ampicillin and vancomycin, whereas only BR3 was resistant to tetracycline. The current investigation, along with earlier reported work on these isolates, identifies BR3 as a useful isolate in the industrial application for the degradation of EtBr. Identical and related microorganisms, which are available in the culture collection repositories, can also be explored for such potential to formulate a microbial consortium for the bioremediation of ethidium bromide prior to its disposal. [ABSTRACT FROM AUTHOR]

Background: MDR in bacteria is threatening to public health. Overexpression of efflux pumps is an important cause of MDR. The co-administration of antimicrobial drugs and efflux pump inhibitors (EPIs) is a promising approach to address the problem of MDR.Objectives: To identify new putative EPIs and to characterize their mechanisms of action.Methods: The effects of four selected piperazine derivatives on resistance-nodulation-cell division (RND) pumps was evaluated in Escherichia coli strains overexpressing or not expressing RND pumps by assays aimed at evaluating antibiotic potentiation, membrane functionality, ethidium bromide accumulation and AcrB expression. The cytotoxicity of selected piperazines towards primary cultures of human dermal fibroblasts was also investigated.Results: Four molecules enhanced levofloxacin activity against strains overexpressing RND efflux pumps (AcrAB-TolC and AcrEF-TolC), but not against RND pump-deficient strains. They had little effects on membrane potential. Molecule 4 decreased, whereas the other three increased, membrane permeability compared with untreated control cells. The four molecules showed differences in the specificity of interaction with RND efflux pumps, by inactivating the transport of one or more antibiotics, and in the levels of ethidium bromide accumulation and of acrB expression inhibition.Conclusions: Piperazine derivatives are good candidates as inhibitors of RND efflux pumps. They decreased the activity of RND pumps by mixed mechanisms of action. Small structural differences among the molecules can be critical in defining their behaviour. [ABSTRACT FROM AUTHOR]

Cu(II) complex of 2-hydroxy-5-methoxyacetophenone-N(4)-ethyl thiosemicarbazone (Cu(HMAET)Cl) was synthesized and characterized by spectroscopic methods such as FT-IR, ¹H-NMR and UV-Vis. The Cu(II) complex's DNA-binding capacity was studied with the UV-Vis absorption titration and ethidium bromide (EB) displacement experiment using E. coli DNA. The results demonstrated that the Cu(II) complex could intercalate in the DNA's base pairs. The binding constant was found as 2.8x107 M-1. Also, the interaction study of the Cu(II) complex with bovine serum albumin (BSA) was investigated using the UV-Vis absorption and fluorescence spectroscopy techniques. It was concluded that the Cu(II) complex interacts strongly with BSA. [ABSTRACT FROM AUTHOR]

• The polyoxometalate compounds, stabilized by the biologically relevant ethidium counter cations. • The binding studies of Keggin-Ethidium hybrid with CT-DNA (calf thymus DNA). • The single crystal X-ray structure of Keggin-Ethidium hybrid compounds. • The supramolecular interactions between Keggin polyanion and ethidium cation. We report the synthesis and photoluminescence (PL) properties of three compounds [C 21 H 20 N 3 ] 2 [HPMo 12 O 40 ] (1), [C 21 H 20 N 3 ] 3 [PW 12 O 40 ]∙4C 3 H 7 NO (2) and [C 21 H 20 N 3 ] 4 [SiW 12 O 40 ] (3) consisting of ethidium cation (3,8-diamino-5-ethyl-6-phenylphenanthridinium) and Keggin type polyoxometalates. Compounds 1, 2 and 3 have been characterized unambiguously by the single crystal X-ray diffraction studies. The binding studies of inorganic-organic hybrid compounds 1, 2 and 3 with CT-DNA (calf thymus DNA) have been carried out and monitored by UV–Vis- and emission-spectroscopy. The compounds 1 and 2 show fluorescence enhancement where as compound 3 with silicotungstate polyanion shows fluorescence quenching. The photoluminescence properties of three hybrid compounds arise due to the interaction of ethidium cation with DNA. We have demonstrated that the interaction between ethidium cation and CT-DNA is influenced by a particular type of polyoxometalate (POM) Keggin anion. The crystal structures show supramolecular interactions between the Keggin anion and ethidium cation. Compounds 1, 2 and 3 are further characterized by routine spectral analysis. [Display omitted] [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is a pathological condition characterized by the demyelination of nerve fibers, primarily attributed to the destruction of oligodendrocytes and subsequent motor neuron impairment. Ethidium bromide (EB) is a neurotoxic compound that induces neuronal degeneration, resulting in demyelination and symptoms resembling those observed in experimental animal models of multiple sclerosis (MS). The neurotoxic effects induced by EB in multiple sclerosis (MS) are distinguished by the death of oligodendrocytes, degradation of myelin basic protein (MBP), and deterioration of axons. Neurological complications related to MS have been linked to alterations in the signaling pathway known as smo-shh. Purmorphine (PUR) is a semi-synthetic compound that exhibits potent Smo-shh agonistic activity. It possesses various pharmacological properties, including antioxidant, anti-inflammatory, anti-apoptotic, and neuromodulatory effects. Hence, the current investigation was conducted to assess the neuroprotective efficacy of PUR (at doses of 5 and 10 mg/kg, administered intraperitoneally) both individually and in conjunction with Fingolimod (FING) (at a dose of 0.5 mg/kg, administered intraperitoneally) in the experimental model of MS induced by EB. The administration of EB was conducted via the intracerebropeduncle route (ICP) over a period of seven days in the brain of rats. The Wistar rats were allocated into six groups using randomization, each consisting of eight rats (n = 8 per group). The experimental groups in this study were categorized as follows: (I) Sham Control, (II) Vehicle Control, (III) PUR per se, (IV) EB, (V) EB + PUR5, (VI) EB + PUR10, (VII) EB + FING 0.5, and (VIII) EB + PUR10 + FING 0.5. On the final day of the experimental timeline, all animal subjects were euthanized, and subsequent neurochemical estimations were conducted on cerebrospinal fluid, blood plasma, and brain tissue samples. In addition, we conducted neurofilament (NFL) analysis and histopathological examination. We utilized the luxol myelin stain to understand better the degeneration associated with MS and its associated neurological complications. The findings of our study indicate that the activation of SMO-Shh by PUR has a mitigating effect on neurobehavioral impairments induced by EB, as well as a restorative effect on cellular and neurotransmitter abnormalities in an experimental model of MS., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

This study aimed to evaluate the antibacterial and inhibitory action of NorA, Tet(K), MsrA and MepA efflux pumps in S. aureus strains using the sesquiterpenes named trans-caryophyllene and caryophyllene oxide, both isolated and encapsulated in liposomes. The antibacterial and inhibitory action of these efflux pumps was evaluated through the serial microdilution test in 96-well microplates. Each sesquiterpene and liposome/sesquiterpene was combined with antibiotics and ethidium bromide (EtBr). The antibiotics named norfloxacin, tetracycline and erythromycin were used. The 1199 B, IS-58, RN4220 and K2068 S. aureus strains carrying NorA, Tet(K), MsrA and MepA, respectively, were tested. In the fluorescence measurement test, K2068 S. aureus was incubated with the sesquiterpenes and EtBr, and the fluorescence emission by EtBr was measured. The tested substances did not show direct antibacterial activity, with MIC >1024 μg/mL. Nonetheless, the isolated trans-caryophyllene and caryophyllene oxide reduced the MIC of antibiotics and EtBr, indicating inhibition of NorA, Tet(K) and MsrA. In the fluorescence test, these same sesquiterpenes increased fluorescence emission, indicating inhibition of MepA. Therefore, the sesquiterpenes named trans-caryophyllene and caryophyllene oxide did not show direct antibacterial action; however, in their isolated form, they showed possible inhibitory action on NorA, Tet(K), MsrA and MepA efflux pumps. They may also act in antibiotic potentiation. Further studies are needed to identify the mechanisms involved in antibiotic potentiation and efflux pump inhibitory action., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

• Therapeutic potential of Embelin against Ethidium Bromide-Induced Multiple Sclerosis in Rats. • Role of Embelin against the motor deficit and biochemical abnormalities in rats. • Role of Embelin against neurochemical, neuroinflammatory, and histological alterations in rats. Multiple sclerosis (MS) is a debilitating inflammatory disease characterized by demyelination, varied remyelination conservation, and partial axonal retention in central nervous system (CNS) lesions. The p38 mitogen-activated protein kinase (MAPK) pathway has been implicated in the pathophysiology of MS. Embelin (EMB), derived from the Embelia ribes plant, possesses diverse biological activities, including anti-inflammatory properties. This study aimed to investigate the neuroprotective effects of EMB in an ethidium bromide (EB)-induced model of MS in Wistar rats. Wistar rats were randomly divided into five groups (n = 8). MS-like manifestations were induced by injecting EB (0.1 %/10 µl) into the intracerebropeduncle (ICP) region of the rat brain for seven consecutive days. EMB was administered at doses of 1.25, 2.5, and 5 mg/kg. Behavioral assessments, neuroinflammatory cytokine analysis like tumor necrosis factor-α, interleukin-1-β, interleukin-6 (TNF-α, IL-1β, IL-6), oxidative stress marker measurements malondialdehyde, reduced glutathione, superoxide dismutase (MDA, GSH, SOD), and nitrite (NO), Acetylcholinesterase enzyme (AchE), and neurotransmitter level analysis, dopamine, serotonin, and norepinephrine (DA, 5-HT, and NE) were conducted. The study assessed behavioral, neurochemical, biochemical, and neuroinflammatory parameters, along with the modulation of p38 MAPK signaling. EMB administration significantly ameliorated neurological consequences induced by EB, improving motor coordination and gait abnormalities in rats. Furthermore, EMB effectively reduced neuroinflammatory cytokines (TNF-α, IL-1β, IL-6) and oxidative stress markers (AchE, SOD, MDA, GSH, nitrite). Notably, EMB exhibited a modulatory effect on neurotransmitter levels, increasing GABA, DA, and 5-HT, while reducing glutamate in EB-treated groups. This study demonstrates the neuroprotective potential of EMB against the EB-induced model of MS in rats. EMB administration mitigated neurological impairments, attenuated neuroinflammation, alleviated oxidative stress, and restored neurotransmitter balance. These findings highlight the promise of EMB as a therapeutic candidate for MS treatment, providing insights into its potential mechanism of action involving the modulation of p38 MAPK signaling. [ABSTRACT FROM AUTHOR]

The present study is focused on application of a natural compound, 3, 5-dihydroxy 4', 7-dimethoxyflavone (DHDM) from a medicinal plant Alpinia nigra for nucleic acid detection and differential cell staining. DHDM was found to interact with nucleic acid and forms complex, which was investigated for various applications. It was successfully utilized to visualize plasmid, genomic, and ds-linear DNA in agarose gel electrophoresis without affecting the DNA mobility in the gel. Fluorescence of DHDM increased several fold upon binding to dsDNA. Photostability of the compound was assessed and showed photobleaching effect that decreased gradually over time. Application of the compound was further extended to differential cell staining. When observed in fluorescence microscope, DHDM stained the dead cells and differentiated them from live cells in the case of bacterial, yeast, and mammalian cells. Higher concentration of the compound was found to be less cytotoxic to cancerous cells. Nucleic acid staining dyes like Ethidium bromide (EtBr), Propidium iodide (PI), etc. are carcinogens and environmental pollutants and therefore DHDM a natural compound, is a major benefit and thus can serve as an alternative to the current dyes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Glycated hemoglobin (GHb) found in mammals undergoes irreversible damage when exposed to external redox agents, which is much more vulnerable than its normal counterpart hemoglobin (Hb). Besides the oxygen regulation throughout the body, Hb plays a vital role in balancing immunological health and the redox cycle. Photoinduced ultra-fast electron transfer phenomena actively participate in regulation of various kind of homeostasis involved in such biomacromolecules. In the present study we have shown that a well-known mutagen Ethidium Bromide (EtBr) reduces GHb in femtosecond time scale (efficiently) upon photoexcitation after efficient recognition in the biomolecule. We have performed similar experiment by colocalizing EtBr and Iron (Fe(III)) on the micellar surface as Hb mimic in order to study the excited state EtBr dynamics to rationalize the time scale obtained from EtBr in GHb and Hb. While other experimental techniques including Dynamic Light Scattering (DLS), Zeta potential, absorbance and emission spectroscopy have been employed for the confirmation of structural perturbation of GHb compared to Hb, a detailed computational studies involving molecular docking and density functional theory (DFT) have been employed for the explanation of the experimental observations., (© 2024 Wiley-VCH GmbH.)

Reactive oxygen species (ROS) play a key role in the regulation of cellular metabolism in physiological and pathological processes. Physiological ROS production plays a central role in the spatial and temporal modulation of normal cellular functions such as proliferation, signaling, apoptosis, and senescence. In contrast, chronic ROS overproduction is responsible for a wide spectrum of diseases, such as cancer, cardiovascular disease, and diabetes, among others. Quantifying ROS levels in an accurate and reproducible manner is thus essential to understanding normal cellular functionality. Fluorescence imaging-based methods to characterize intra-cellular ROS species is a common approach. Many of the imaging ROS protocols in the literature use 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA) dye. However, this dye suffers from significant limitations in its usage and interpretability. The current protocol demonstrates the use of a dihydroethidium (DHE) fluorescent probe as an alternative method to quantify total ROS production in a high-throughput setting. The high throughput imaging platform, CX7 Cellomics, was used to measure and quantify the ROS production. This study was conducted in three hepatocellular cancer cell lines - HepG2, JHH4, and HUH-7. This protocol provides an in-depth description of the various procedures involved in the assessment of ROS within the cells, including - preparation of DHE solution, incubation of cells with DHE solution, and measurement of DHE intensity necessary to characterize the ROS production. This protocol demonstrates that DHE fluorescent dye is a robust and reproducible choice to characterize intracellular ROS production in a high-throughput manner. High throughput approaches to measure ROS production are likely to be helpful in a variety of studies, such as toxicology, drug screening, and cancer biology.

Ivermectin is a sixteen-membered macrolactone "wonder drug" of Nobel prize-honored distinction that exhibits a wide range of antiparasitic activities. It has been used for almost four decades in the treatment of various parasitic diseases in humans and animals. In this paper, we describe the synthesis of the first-in-class ivermectin derivatives obtained via derivatization of the C13 position, along with the unexpected rearrangement of the oxahydrindene (hexahydrobenzofuran) unit of the macrolide ring. The structural investigation of the rearrangement has been performed using the single-crystal X-ray diffraction method. The antiparasitic and cytotoxic activities of the newly synthesized derivatives were determined in vitro with the bloodstream form of Trypanosoma brucei brucei, the hepatic stage of Plasmodium berghei, and human leukemia HL-60 cells. The compounds with the highest trypanocidal activity were the C13-epi-2-chloroacetamide analogs of native (6h) or rearranged (7h) ivermectin. Both 6h and 7h displayed trypanocidal activities within a similar mid-nanomolar concentration range as the commercially used trypanocides suramin and ethidium bromide. Furthermore, 6h and 7h exhibited a comparable cytotoxic to trypanocidal ratio as the reference drug ethidium bromide. The double-modified compound 7a (C13-epi-acetamide of rearranged ivermectin) exhibited the highest activity against P. berghei grown in human hepatoma cells, which was 2.5 times higher than that of ivermectin. The findings of this study suggest that C13-epi-amide derivatives of ivermectin are suitable leads in the rational development of new antiparasitic agents., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

We have set-up an electrochemical advanced oxidation process for ethidium bromide (1), based on the Eu-doped MnWO 4 (Eu:MnWO 4), obtained through a template-driven synthesis, along with developing a suitable monitoring method. Under galvanostatic conditions, Eu:MnWO 4 -coated graphite electrode serves as anode, applicable for removal of 1. To go further and augment the catalytic method, we have applied a modified carbon paste electrode for the monitoring of 1 with the limit of detection (LOD) of 54 nM. Enhancement of the hydrogen evolution reaction is an indication of electrocatalytic properties of the material, whereby developed method emerges as a candidate for straightforward application in electrochemical advanced oxidation processes (EAOPs). We have enriched experimental data with theoretical insights, provided by Density Functional Theory (DFT), and proposed oxidation mechanism of 1. Based on obtained results, we propose the new nanomaterial as a potent electrochemical modifier, suitable for catalytic treatment and process monitoring of the 1 -polluted waters. [Display omitted] • Eu:MnWO 4 -based nanomaterial for ethidium bromide sensing and control. • A novel analytical approach for both ethidium bromide degradation and concentration monitoring. • Ethidium bromide degradation mechanism was studied theoretically. • The practical feasibility of this system was tested by monitoring the treated water parameters. [ABSTRACT FROM AUTHOR]

The online version of the original article can be found at https://doi.org/10.1007/s11011-020-00536-z. 10.1007/s12640-021-00410-5. 34554409 2 Sharma Y, Garabadu D. Ruthenium red, mitochondrial calcium uniporter inhibitor, attenuates cognitive deficits in STZ-ICV challenged experimental animals. [Extracted from the article]

Levofloxacin (HLVX), a quinolone antimicrobial agent, when deprotonated (LVX - ) behaves as a bidentate ligand, and it coordinates to Co 2+ through the pyridone oxygen and the carboxylate oxygen. Along with two imidazole (ImH) ligands, levofloxacin forms a Co(II)-Levofloxacin-imidazole complex, [CoCl(LVX)(ImH) 2 (H 2 O)]·3H 2 O (abbreviated henceforth as CoLevim) which was isolated and characterized by 1 H and 13 C NMR spectroscopy, UV-visible and FT-IR spectroscopy, powder X-ray diffraction and thermal analysis methods. CoLevim shows promise in its antimicrobial activities when tested against microorganisms (Bacillus cereus, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, Salmonella typhimurium and Escherichia coli). Fluorescence competitive studies with ethidium bromide (EB) revealed that CoLevim can compete with EB and displace it to bind to CT-DNA through intercalative binding mode. In addition, CoLevim exhibited a good binding propensity to BSA proteins with relatively high binding constants. The antioxidant activities of the free ligands and CoLevim were determined in vitro using ABTS + radical (TEAC assay). The Co-complex showed a better antioxidant capacity with inhibitory concentrations (IC 50 ) of 40 μM than the free ligands. CoLevim also showed noteworthy apoptotic potential and behaved as an efficient resistant modifying agent when its antiproliferative potential was examined by MTT assay using the breast cancer cell lines (MCF7, MCF7Dox/R and MCF7Pacli/R cells)., Competing Interests: Declaration of competing interest There is no conflict of interest regarding the research work., (Copyright © 2023 Elsevier B.V. All rights reserved.)

We demonstrate a rapid and sensitive method for DNA detection without the need for fluorescence. This is based on carbon-coated magnetic iron (Fe) microparticles with a covalent surface attachment of DNA. We show that these magnetic microparticles can capture complementary DNA. Significantly, the DNA covalent surface bonds are robust to high temperatures and can be included in a sample during polymerase chain reaction (PCR). This method is employed for the detection of targeted DNA sequences (40-50 bp). Hybridization probes on the surface of the magnetically susceptible Fe microparticle recognize the target DNA sequence-specifically. The double-stranded DNA (dsDNA) microparticles are then quickly captured with a magnet from the sample matrix. This foregoes postpurification processes, such as electrophoresis, which make our technique time- and cost-effective. Captured dsDNA can be detected with intercalating dyes such as ethidium bromide through a loss in the UV absorption signal with a limit of detection (LOD) of 24 nM within 15 min. Likewise, surface-bound DNA can act as a primer in PCR to decrease the LOD to 5 pM within 2 h. This is the first instance of a nucleotide-modified magnetically susceptible carbon substrate that is PCR-compatible. Besides DNA capture, this strategy can eventually be applied to sequence-specific nucleic acid purification and enrichment, PCR cleanup, and single-strand generation. The DNA-coated particles are stable under PCR conditions (unlike commonly used polystyrene or gold particles).

The aim of the study was to track the spread of antimicrobial resistance among the different sectors of One Health through the detection of Multidrug-Efflux-System in multidrug-resistant Staphylococcus aureus isolates. Multidrug-resistant (MDR) and methicillin-resistant (MRSA) S. aureus isolates were selected: 25 of human, one of animal and eight of food origin. The efflux system genes norA, norB, norC, LmrS, tet38 and msrA were screened by PCR. The activity of the efflux systems was determined by the minimum inhibitory concentration (MIC) of tetracycline and ciprofloxacin in the presence and absence of CCCP and in the quantification of ethidium bromide efflux. Furthermore, biofilm formation was determined in the presence and absence of the CCCP. The molecular epidemiology of the isolates was traced with the aid of PFGE. The gene norC was the most prevalent, detected in all isolates and msrA was the least prevalent, detected in only two isolates from humans. There was no difference in the MICs of tetracycline and ciprofloxacin in the presence of CCCP, but 55.9% of isolates showed ethidium bromide efflux. The presence of CCCP decreased the biofilm formation. Regarding the molecular epidemiology, in three clusters was a mixture of the isolates from different origins. Therefore, S. aureus MDR with active multidrug efflux systems are circulating between One Health domains and it is necessary to consider strategies to decrease this circulation in order to prevent the dissemination of resistance mediated by MES., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Efflux and motility are two key biological functions in bacteria. Recent findings have shown that efflux impacts flagellum biosynthesis and motility in Escherichia coli and other bacteria. AcrR is known to be the major transcriptional repressor of AcrAB-TolC, the main multidrug efflux pump in E. coli and other Enterobacteriaceae . However, the underlying molecular mechanisms of how efflux and motility are co-regulated remain poorly understood. Here, we have studied the role of AcrR in direct regulation of motility in E. coli . By combining bioinformatics, electrophoretic mobility shift assays (EMSAs), gene expression, and motility experiments, we have found that AcrR represses motility in E. coli by directly repressing transcription of the flhDC operon, but not the other flagellum genes/operons tested. flhDC encodes the master regulator of flagellum biosynthesis and motility genes. We found that such regulation primarily occurs by direct binding of AcrR to the flhDC promoter region containing the first of the two predicted AcrR-binding sites identified in this promoter. This is the first report of direct regulation by AcrR of genes unrelated to efflux or detoxification. Moreover, we report that overexpression of AcrR restores to parental levels the increased swimming motility previously observed in E. coli strains without a functional AcrAB-TolC pump, and that such effect by AcrR is prevented by the AcrR ligand and AcrAB-TolC substrate ethidium bromide. Based on these and prior findings, we provide a novel model in which AcrR senses efflux and then co-regulates efflux and motility in E. coli to maintain homeostasis and escape hazards. IMPORTANCE Efflux and motility play a major role in bacterial growth, colonization, and survival. In Escherichia coli , the transcriptional repressor AcrR is known to directly repress efflux and was later found to also repress flagellum biosynthesis and motility by Kim et al. (J Microbiol Biotechnol 26:1824-1828, 2016, doi: 10.4014/jmb.1607.07058). However, it remained unknown whether AcrR represses flagellum biosynthesis and motility directly and through which target genes, or indirectly because of altering the amount of efflux. This study reveals that AcrR represses flagellum biosynthesis and motility by directly repressing the expression of the flhDC master regulator of flagellum biosynthesis and motility genes, but not the other flagellum genes tested. We also show that the antimicrobial, efflux pump substrate, and AcrR ligand ethidium bromide regulates motility via AcrR. Overall, these findings support a novel model of direct co-regulation of efflux and motility mediated by AcrR in response to stress in E. coli ., Competing Interests: The authors declare no conflict of interest.

The efflux pump mechanism contributes to the antibiotic resistance of widely distributed strains of Staphylococcus aureus. Therefore, in the present work, the ability of the riparins N-(4-methoxyphenethyl)benzamide (I), 2-hydroxy-N-[2-(4-methoxyphenyl)ethyl]benzamide (II), 2, 6-dihydroxy-N-[ 2-(4-methoxyphenyl)ethyl]benzamide (III), and 3,4,5-trimethoxy-N-[2-(4-methoxyphenethyl)benzamide (IV) as potential inhibitors of the MepA efflux pump in S. aureus K2068 (fluoroquinolone-resistant). In addition, we performed checkerboard assays to obtain more information about the activity of riparins as potential inhibitors of MepA efflux and also analyzed the ability of riparins to act on the permeability of the bacterial membrane of S. aureus by the fluorescence method with SYTOX Green. A molecular coupling assay was performed to characterize the interaction between riparins and MepA, and ADMET (absorption, distribution, metabolism, and excretion) properties were analyzed. We observed that I-IV riparins did not show direct antibacterial activity against S. aureus. However, combination assays with substrates of MepA, ciprofloxacin, and ethidium bromide (EtBr) revealed a potentiation of the efficacy of these substrates by reducing the minimum inhibitory concentration (MIC). Furthermore, increased EtBr fluorescence emission was observed for all riparins. The checkerboard assay showed synergism between riparins I, II, and III, ciprofloxacin, and EtBr. Furthermore, riparins III and IV exhibited permeability in the S. aureus membrane at a concentration of 200 μg/mL. Molecular docking showed that riparins I, II, and III bound in a different region from the binding site of chlorpromazine (standard pump inhibitor), indicating a possible synergistic effect with the reference inhibitor. In contrast, riparin IV binds in the same region as the chlorpromazine binding site. From the in silico ADMET prediction based on MPO, it could be concluded that the molecules of riparin I-IV present their physicochemical properties within the ideal pharmacological spectrum allowing their preparation as an oral drug. Furthermore, the prediction of cytotoxicity in liver cell lines showed a low cytotoxic effect for riparins I-IV., Competing Interests: Declaration of competing interest The authors declare no conflict of interest, financial or otherwise., (Copyright © 2023 Elsevier Inc. All rights reserved.)