Intracellular Resistance Research Articles

Localized heating coupling with radical oxidation eliminating antibiotic resistance genes (ARGs) in interfacial photothermal Fenton-like disinfection process

Conventional oxidative disinfection processes are inefficient in eliminating intracellular antibiotic resistance genes (iARGs) due to the barrier of the cell membrane and the competitive reaction of cellular constituents within antibiotic-resistant bacteria (ARB), resulting in the widespread prevalence of ARGs in recycled water. This study presented the first application of localized heating coupling with advanced oxidation to destroy the resistant Escherichia coli cells and improved subsequent iARGs (blaTEM-1) degradation in a novel photothermal Fenton-like disinfection process. The Fe-Mn@CNT microfiltration membrane, comprising carbon nanotubes wrapped with Fe and Mn nanoparticles (Fe-Mn@CNT), was employed as a nanomaterial for photothermal conversion and H2O2 activation. The highly efficient absorption of full-spectrum photons by CNTs enabled the Fe-Mn@CNT membrane to concentrate light to generate localized intense heat, resulting in the destruction of ARB nearby, and the subsequent release of iARGs. Interfacial heat favored Fe-Mn-induced H2O2 activation, leading to the production of more ·OH, which in turn promoted the oxidation for ARG degradation and ARB cell damage. The results of the acetylcysteine quenching experiments indicated that interfacial heating and radical oxidation-induced accumulation of intracellular reactive oxygen species contributed to the elimination of about 1-log iARGs through direct attack. The integrity of the cell membrane, the morphology of ARB and the variation of i/e ARG copy numbers were observed to reveal that the introduction of interfacial heating aggravated the cell lysis and accelerated the iARGs release, resulting in the inactivation of 7.27-log ARB and the elimination of 4.64-log iARGs and 2.23-log eARGs. Localized heating coupling with ·OH oxidation achieved a 143 % increase in iARGs removal compared to the conventional Fenton-like oxidation. The interfacial photothermal Fenton-like disinfection process exhibited remarkable material stability, robust disinfection performance, and effective suppression of horizontal gene transfer, underscoring its immense potential to mitigate the risk of ARG dissemination in reclaimed water systems.

Mechanisms of horizontal gene transfer and viral contribution to the fate of intracellular and extracellular antibiotic resistance genes in anaerobic digestion supplemented with conductive materials under ammonia stress

The addition of conductive materials (CMs) is an effective strategy for mitigating ammonia inhibition during anaerobic digestion (AD). However, the introduction of CMs can result in increased antibiotic resistance genes (ARGs) pollution, potentially facilitated by enhanced horizontal gene transfer (HGT). The complex dynamics of intracellular and extracellular ARGs (iARGs/eARGs) and the mechanisms underlying their transfer, mediated by CMs, in ammonia-stressed AD systems remain unclear. In this study, we investigated the effects of three commonly used CMs—nano magnetite (Mag), nano zero-valent iron (nZVI), and granular activated carbon (GAC)—on the fate of iARGs and eARGs during the AD of waste activated sludge under ammonia stress. The results revealed an unexpected enrichment of iARGs by 1.5 %–10.9 % and a reduction of eARGs by 14.1 %–25.2 % in CM-supplemented AD. This discrepancy in the dynamics of iARGs and eARGs may be attributed to changes in microbial hosts and the horizontal transfer of ARGs. Notably, CMs activated prophages within antibiotic-resistant bacteria (ARB) and their symbiotic partners involved in vitamin B12 provision, leading to the lysis of ARB and the subsequent release of eARGs for transformation. Additionally, the abundance of potentially mobile ARGs, which co-occurred with mobile genetic elements, increased by 56.6 %–134.5 % with CM addition, highlighting an enhanced potential for the HGT of ARGs. Specifically, Mag appeared to promote both transformation and conjugation processes, while nZVI only promoted conjugation. Moreover, none of the three CMs had any discernible impact on transduction. GAC proved superior to both nano Mag and nZVI in controlling the enrichment of iARGs, reducing eARGs, and limiting HGTs simultaneously. Overall, these findings provide novel insights into the role of viruses and the mechanisms of ARG spread in CM-assisted AD, offering valuable information for developing strategies to mitigate ARG pollution in practical applications.

Contrasting Dynamics of Intracellular and Extracellular Antibiotic Resistance Genes in Response to Nutrient Variations in Aquatic Environments.

The propagation of antibiotic resistance in environments, particularly aquatic environments that serve as primary pathways for antibiotic resistance genes (ARGs), poses significant health risks. The impact of nutrients, as key determinants of bacterial growth and metabolism, on the propagation of ARGs, particularly extracellular ARGs (eARGs), remains poorly understood. In this study, we collected microorganisms from the Yangtze River and established a series of microcosms to investigate how variations in nutrient levels and delivery frequency affect the relative abundance of intracellular ARGs (iARGs) and eARGs in bacterial communities. Our results show that the relative abundance of 7 out of 11 representative eARGs in water exceeds that of iARGs, while 8 iARGs dominate in biofilms. Notably, iARGs and eARGs consistently exhibited opposite responses to nutrient variation. When nutrient levels increased, iARGs in the water also increased, with the polluted group (COD = 333.3 mg/L, COD:N:P = 100:3:0.6, m/m) and the eutrophic group (COD = 100 mg/L, COD:N:P = 100:25:5, m/m) showing 1.2 and 3.2 times higher levels than the normal group (COD = 100 mg/L, COD:N:P = 100:10:2, m/m), respectively. In contrast, eARGs decreased by 6.7% and 8.4% in these groups. On the other hand, in biofilms, higher nutrient levels led to an increase in eARGs by 1.5 and 1.7 times, while iARGs decreased by 17.5% and 50.1% in the polluted and eutrophic groups compared to the normal group. Moreover, while increasing the frequency of nutrient delivery (from 1 time/10 d to 20 times/10 d) generally did not favor iARGs in either water or biofilm, it selectively enhanced eARGs in both. To further understand these dynamics, we developed an ARGs-nutrient model by integrating the Lotka-Volterra and Monod equations. The results highlight the complex interplay of bacterial growth, nutrient availability, and mechanisms such as horizontal gene transfer and secretion influencing ARGs' propagation, driving the opposite trend between these two forms of ARGs. This contrasting response between iARGs and eARGs contributes to a dynamic balance that stabilizes bacterial resistance levels amid nutrient fluctuations. This study offers helpful implications regarding the persistence of bacterial resistance in the environment.

Fate of intracellular and extracellular antibiotic resistance genes in sewage sludge by full-scale anaerobic digestion

Storage tank (ST) is a promising strategy for solid-liquid separation following anaerobic digestion (AD). However, little is known regarding the effects of ST on antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and microbial communities. Therefore, this study first investigated eight typical ARGs (sul1, sul2, tetW, tetA, tetO, tetX, ermF, and ermB) and three MGEs (int1, int2, and tnpA) during full-scale AD of sludge and the liquid and biosolids phases of ST. Following that, intracellular ARGs (iARGs), extracellular polymeric substances (EPS)-associated ARGs, and cell-free ARGs removal were quantified in AD process, which is largely unknown for full-scale AD of sludge. The qPCR results showed that both AD and ST significantly removed ARGs, with ST biosolids showing the highest removal efficiency for the total measured relative (82.27 ± 2.09 %) and absolute (92.38 ± 0.89 %) abundance of ARGs compared to the raw sludge. Proteobacteria, Bacteroidota, Firmicutes and Campilobacterota were the main potential ARGs hosts in the sludge. Moreover, the results of different ARGs fractions showed that the total relative and absolute abundance of iARGs decreased by 90.12 ± 0.83 % and 79.89 ± 1.41 %, respectively, following AD. The same trend was observed for the abundance of EPS-associated ARGs, while those of cell-free ARGs increased after AD. These results underscore the risk of extracellular ARGs and provided new insights on extracellular ARGs dissemination evaluation.

Explainable Feature Engineering for Multi-Modal Tissue State Monitoring Based on Impedance Spectroscopy.

One of the most promising approaches to food quality assessments is the use of impedance spectroscopy combined with machine learning. Thereby, feature selection is decisive for a high classification accuracy. Physically based features have particularly significant advantages because they are able to consider prior knowledge and to concentrate the data into pertinent understandable information, building a solid basis for classification. In this study, we aim to identify physically based measurable features for muscle type and freshness classifications of bovine meat based on impedance spectroscopy measurements. We carry out a combined study where features are ranked based on their F1-score, cumulative feature selection, and t-distributed Stochastic Neighbor Embedding (t-SNE). In terms of features, we analyze the characteristic points (CPs) of the impedance spectrum and the model parameters (MPs) obtained by fitting a physical model to the measurements. The results show that either MPs or CPs alone are sufficient for detecting muscle type. Combining capacitance (C) and extracellular resistance (Rex) or the modulus of the characteristic point Z1 and the phase at the characteristic frequency of the beta dispersion (Phi2) leads to accurate separation. In contrast, the detection of freshness is more challenging. It requires more distinct features. We achieved a 90% freshness separation using the MPs describing intracellular resistance (Rin) and capacitance (C). A 95.5% freshness separation was achieved by considering the phase at the end of the beta dispersion (Phi3) and Rin. Including additional features related to muscle type improves the separability of samples; ultimately, a 99.6% separation can be achieved by selecting the appropriate features.

Impact of chlorine disinfection on intracellular and extracellular antimicrobial resistance genes in wastewater treatment and water reclamation

Wastewater treatment plants and water reclamation facilities are reservoirs of antimicrobial resistance genes (ARGs). These ARGs are not limited solely to intracellular DNA (inARGs) but include extracellular DNA (exARGs) present in wastewater. The release of exARGs from cells can be exacerbated by treatment processes, including chlorine disinfection, which disrupts bacterial cells. Given the potential for exARGs to drive horizontal gene transfer and contribute to the proliferation of antimicrobial resistance, it is imperative to recognize these fractions as emerging environmental pollutants. In this study, we conducted a comprehensive year-long assessment of both inARGs and exARGs, further differentiating between dissolved exARGs (Dis_exARGs) and exARGs adsorbed onto particulate matter (Ads_exARGs), within a full-scale wastewater treatment and water reclamation facility. The results revealed that Ads_exARGs comprised up to 30 % of the total ARGs in raw sewage with high biomass content. Generally, treatments at low and high doses of chlorine increased the abundance of Dis_exARGs and Ads_exARGs. The fate of ARG levels that varied depending on the type of ARGs suggested variations in the susceptibility of the host bacteria to chlorination. Moreover, co-occurrence of several potential opportunistic pathogenic bacteria and ARGs were observed. Therefore, we propose higher doses of chlorination as a prerequisite for the effective removal of inARGs and exARGs.

Effects of polyvinyl chloride microplastics and benzylalkyldimethylethyl compounds on system performance, microbial community and resistance genes in sulfur autotrophic denitrification system

Benzylalkyldimethylethyl ammonium compounds (BAC) and polyvinyl chloride microplastics (PVC MPs), as the frequently detected pollutants in wastewater treatment plants (WWTPs), have attracted more concerns on their ecosystem risks. Therefore, this study investigated how the sulfur autotrophic denitrification (SAD) system responded to the single and joint stress of PVC MPs (1, 10 and 100 mg/L) and BAC (0.5, 5 and 10 mg/L). After 100 days of operation, the presence of 10 mg/L BAC led to obviously inhibitory effects on system performance and microbial metabolic activity. And the additions of PVC MPs or/and BAC stimulated the proliferation of intracellular resistance genes (RGs), whereas exposure to BAC increased the abundances of extracellular RGs and free RGs in water more significantly. Compared to the joint stress, BAC single stress resulted in higher abundances of free RGs in water, which further increased the risk of RGs propagation. Moreover, the interaction between mobile genetic elements and extracellular polymeric substances further increased the spread of RGs. Pathogens might be the potential hosts of RGs and enriched in SAD system and plastisphere, thereby leading to more serious ecological risks. This study will broaden the understanding of the environmental hazards posed by PVC MPs and BAC in WWTPs.

Removal of intracellular and extracellular antibiotic resistance genes and virulence factor genes using electricity-intensified constructed wetlands

Constructed wetland (CW) is considered a promising technology for the removal of emerging contaminants. However, its removal performance for antibiotic resistance genes (ARGs) is not efficient and influence of virulence factor genes (VFGs) have not been elucidated. Here, removal of intracellular and extracellular ARGs as well as VFGs by electricity-intensified CWs was comprehensively evaluated. The two electrolysis-intensified CWs can improve the removal of intracellular ARGs and MGEs to 0.96- and 0.85-logs, respectively. But cell-free extracellular ARGs (CF-eARGs) were significantly enriched with 1.8-logs in the electrolysis-intensified CW. Interestingly, adding Fe-C microelectrolysis to the electrolysis-intensified CW is conducive to the reduction of CF-eARGs. However, the detected number and relative abundances of intracellular and extracellular VFGs were increased in all of the three CWs. The biofilms attached onto the substrates and rhizosphere are also hotspots of both intracellular and particle-associated extracellular ARGs and VFGs. Structural equation models and correlation analysis indicated that ARGs and VFGs were significantly cooccurred, suggesting that VFGs may affect the dynamics of ARGs. The phenotypes of VFGs, such as biofilm, may act as protective matrix for ARGs, hindering the removal of resistance genes. Our results provide novel insights into the ecological remediation technologies to enhance the removal of ARGs.

Removal of intracellular antibiotic resistance genes by activating peroxymonosulfate with Co3O4@CNT catalytic membrane

The removal of antibiotic resistance genes (ARGs) is crucial to prevent the proliferation of antibiotic resistance. In this study, we successfully removed intracellular ARGs using the PMS/Co@CM system, which involved activating peroxymonosulfate (PMS) with a catalytic membrane composed of Co3O4 and carbon nanotubes. In the PMS/Co@CM system, 1O2 was the primary reactive oxygen species (ROS) responsible for intracellular ARGs removal. However, the presence of sulfamethoxazole (SMX) in the water samples significantly reduced the efficiency of removing intracellular ARGs in the PMS/Co@CM system although SMX was degraded by •SO4−. This can be attributed to the selective pressure of SMX, which elevated intracellular Superoxide Dismutase (SOD) levels while decreasing Propidium Iodide (PI) levels in cells. Consequently, this led to heightened antioxidant defense and reduced membrane permeability, thereby enhancing cell resistance to 1O2 generated by the PMS/Co@CM system. Encouragingly, a typical UV disinfection process facilitated the removal of residual intracellular ARGs in the effluent of the PMS/Co@CM system, attributed to decreased SOD levels and increased intracellular 1O2 by UV irradiation. These findings contribute to the theoretical understanding of effective ARGs removal and aid in the development of more efficient removal technologies.

The combination of ciprofloxacin and dialkyldimethyl ammonium compound synergistically proliferated intracellular resistance genes in nitrifying system

Antibiotics and quaternary ammonium compounds (QACs) usually co-exist in wastewater treatment plants. Hence, three sequencing batch reactors were established and named as R1, R2 and R3, to investigate the effects of individual and combined exposure of different concentrations of ciprofloxacin (CIP) (0.2, 1.0 and 2.0 mg/L) and dialkyldimethyl ammonium compound (DADMAC) (0.4, 2.0 and 4.0 mg/L) on the performance, microbial community structures and resistance genes (RGs) in nitrifying system during 150 days. Results showed that CIP had a slight effect on ammonia oxidation activity, while 2.0 and 4.0 mg/L DADAMAC could obviously inhibit it, and the combination of CIP and DADMAC had a synergistic inhibitory effect. Besides, both CIP and DADMAC caused partial nitrification, and the order of nitrite accumulation rate was ranked as R3 > R2 > R1. The combination of CIP and DADMAC had an antagonistic effect on the increase of sludge particle size and α-Helix/(β-Sheet + Random coil) was lowest in R3 (0.40). The combination of CIP and DADMAC synergistically stimulated most intracellular RGs in sludge, and the relative abundances of target RGs (e.g., qacEdelta1-01, qacH-01 and qnrS) at the end of operation in R3 were increased by 4.61–18.19 folds compared with those in CK, which were 1.34–5.57 folds higher than the R1 and R2. Moreover, the combination of CIP and DADMAC also promoted the transfer of RGs from sludge to water and enriched more potential hosts of RGs, further promoting the spread of RGs in nitrifying system. Thus, the combined pollution of CIP and DADMAC in wastewaters should attract more attentions.

Response of nitrification system to co-exposure of sucralose and single or combined disinfectants: Reducing damage to nitrification performance and aggravating the spread of intracellular resistance genes

Sucralose (SUC) is an artificial sweetener for everyday consumption and often co-exists with disinfectants such as triclosan (TCS) and dialkyldimethyl ammonium compound (DAC) in sewage. Considering their continuous accumulation in sewage, it is essential to understand the impacts of their single and combined stress on the evolution of resistance genes (RGs) and microorganisms. In this study, three sequencing batch reactors (SBRs) were established, which were added with SUC, disinfectant, SUC and disinfectant, respectively, and named SSBR, DSBR and SDSBR in turn. There were four stages in total, the first two stages and the latter two stages were set to explore the effects of co-exposure of SUC and single disinfectant (TCS), SUC and combined disinfectants (TCS and DAC) on nitrification system, respectively. SSBR showed excellent ammonia oxidation performance in the whole operation stages. Compared with DSBR, the microorganisms in SDSBR under the combined stress of SUC and TCS were less inhibited. TCS and DAC destroyed the ammonia oxidation performance of DSBR and SDSBR. Within 120 days, the removal efficiency of TCS reached 90 %. In SSBR, 1 mg/L SUC promoted the proliferation of RGs, especially induced free RGs in water (w-RGs) to maintain high abundance and persistence. Compared with single stress, the abundances of intracellular RGs in sludge were higher under the combined stress of SUC and TCS, and the risk of RGs transmission was greater. The combined stress of SUC and disinfectants (TCS and DAC) led to a higher enrichment of w-RGs, exacerbating the risk of w-RGs transmission.

Multi-step strategies for synergistic treatment of urinary tract infections based on D-xylose-decorated antimicrobial peptide carbon dots

Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC), often reoccur due to the formation of intracellular bacterial colonies (IBCs) and antibiotic resistance. Given the significance of YadC for UPEC infection in our previous study, we developed D-xylose-decorated ɛ-poly-L-lysine (εPL)-based carbon dots (D-xyl@εPLCDs) that can be traced, and employed multi-step approaches to elucidate the functional roles of D-xyl@εPLCDs in UPEC infection. Compared to undecorated particles, D-xyl@εPLCDs demonstrate YadC-dependent bacterial targeting and exhibit enhanced bactericidal activities both intracellularly and extracellularly. Moreover, pre-treatment of D-xyl@εPLCDs before infection blocked the subsequent adhesion and invasion of UPEC to bladder epithelial cells 5637. Increase of ROS production and innate immune responses were observed in bladder epithelial cells 5637 treated with D-xyl@εPLCDs. In addition, treatment of D-xyl@εPLCDs post-infection facilitated clearance of UPEC in the bladders of the UTI mouse model, and reduced ultimate number of neutrophils, macrophages and inflammatory responses raised by invaded bacteria. Collectively, we presented a comprehensive evaluating system to show that D-xyl@εPLCDs exhibits superior bactericidal effects against UPEC, making them a promising candidate for drug development in clinical UTI therapeutics.

The intracellular concentrations of fluoroquinolones determined the antibiotic resistance response of Escherichia coli

The extensive consumption of antibiotics has been reported to significantly promote the generation of antibiotic resistance (ABR), however, a quantitative causal relationship between antibiotic exposure and ABR response is absent. This study aimed to pinpoint the accurate regulatory concentration of fluoroquinolones (FQs) and to understand the biochemical mechanism of the mutual action between FQ exposure and FQ resistance response. Highly sensitive analytical methods were developed by using UPLC-MS/MS to determine the total residual, extracellular residual, total intracellular, intracellular residual and intracellular degraded concentration of three representative FQs, including ciprofloxacin (CIP), ofloxacin (OFL) and norfloxacin (NOR), with detection limits in the range of 0.002–0.057 μg/L, and recoveries in the range of 80–93%. The MICs of Escherichia coli (E. coli) were 7.0–31.4-fold of the respective MIC0 after 40-day FQ exposure, and significant negative associations were discovered between the intracellular (residual, degraded or the sum) FQ concentrations and FQ resistance. Transcriptional expression and whole-genome sequencing results indicated that reduced membrane permeability and enhanced multi-drug efflux pumps contributed to the decreasing intracellular concentration. These results unveiled the pivotal role of intracellular concentration in triggering FQ resistance, providing important information to understand the dose-response relationship between FQ exposure and FQ resistance response, and ascertain the target dose metric of FQs for eliminating FQ resistance crisis.

Different mobile counter ion types of magnetic ion-exchange resin coupling with ozonation treatment of the organic matter, antibiotic resistance genes, and pathogens in secondary effluent

Advanced treatment and reuse of secondary effluents (SE) from wastewater treatment plants is considered an effective method of alleviating the conflict between water supply and demand. However, the effective removal of organic matter, antibiotic resistance genes (ARGs), and pathogens in SE is key to ensure the safety of reclaimed water. In this study, the effectiveness of three types of magnetic ion-exchange resins (R-X, where X refers to –OH, –HCO3, and -Cl) coupled with ozonation (R + O) in reducing different types of carbon, pathogens, intracellular and extracellular antibiotic resistance genes (iARGs and eARGs), and microbial communities in SE was investigated. The results indicated that R-Cl was the best pre-treatment resin for ozonation. R-Cl + O (8 mL/L R-Cl adsorption for 30 min, followed by 15 min of 8 mg/L ozonation) achieved removal efficiencies of 49.7 %, 86.6 %, 99.9 %, 87.1 %, and 99.9 % for dissolved organic carbon, UV254, ΣiARGs, ΣeARGs, and Σpathogens, respectively. Ozonation was more effective than resin adsorption in the removal of ARGs, and R-Cl + O had the lowest rebounding potential for iARGs and pathogens. In addition, R-OH had the lowest removal efficiency of organic matter, iARGs, and pathogens compared to other types of resins owing to the electrostatic repulsion mechanism. Molecular dynamics simulations and average reduced density gradient analysis revealed that the quaternary amine sites of the resin had a positive surface electrostatic potential, which could firmly adsorb double-stranded deoxyribonucleic acid by electrostatic action. Ozonation effectively reduced the risk of ARGs and pathogens in the effluent of resin. The R + O treatment reduced organic matter, ARGs, and pathogens more effectively than single treatment, despite the different anionic groups of the resin.

Understanding Cancer's Defense against Topoisomerase-Active Drugs: A Comprehensive Review.

In recent years, the emergence of cancer drug resistance has been one of the crucial tumor hallmarks that are supported by the level of genetic heterogeneity and complexities at cellular levels. Oxidative stress, immune evasion, metabolic reprogramming, overexpression of ABC transporters, and stemness are among the several key contributing molecular and cellular response mechanisms. Topo-active drugs, e.g., doxorubicin and topotecan, are clinically active and are utilized extensively against a wide variety of human tumors and often result in the development of resistance and failure to therapy. Thus, there is an urgent need for an incremental and comprehensive understanding of mechanisms of cancer drug resistance specifically in the context of topo-active drugs. This review delves into the intricate mechanistic aspects of these intracellular and extracellular topo-active drug resistance mechanisms and explores the use of potential combinatorial approaches by utilizing various topo-active drugs and inhibitors of pathways involved in drug resistance. We believe that this review will help guide basic scientists, pre-clinicians, clinicians, and policymakers toward holistic and interdisciplinary strategies that transcend resistance, renewing optimism in the ongoing battle against cancer.

Homogeneous vs. heterogeneous photo-Fenton elimination of antibiotic-resistant bacteria bearing intracellular or extracellular resistance: Do resistance mechanisms interfere with disinfection pathways?

The present study aimed to fill the knowledge gap between the implications of intracellular and extracellular antibiotic resistance mechanisms may inflict on the inactivation pathways of the photo-Fenton process under mild conditions. It was thus designed as a cross-comparison of the effect of homogeneous and heterogeneous photo-Fenton (near-neutral pH, [Fe]=1 mg/L, and [H2O2]=10 mg/L) on seven strains of Staphylococcus aureus exhibiting different mechanisms of antibiotic resistance, or susceptibility. Additionally, variations in antibiotic tolerance (MIC test) and relative changes in the presence of antibiotic resistance genes were qualitatively monitored during treatment using PCR. The results suggest that resistance to antibiotics does not confer enhanced resistance to photo-Fenton, as it attained a 4-logU reduction within 50–100 min for all strains, regardless of resistance status. Strains that express intracellular resistance mechanisms do not pose a risk; however, strains that express external mechanisms for their defense against antibiotics occasionally interfere with the inactivation process. This phenomenon was mainly linked to the cell wall thickening of some of the externally resistant strains as compared to their susceptible homologues. Eventually, by conferring resistance to antibiotics, this cell wall alteration may reduce susceptibility to Fenton-related reagents by either reducing their intracellular diffusion or rendering cell walls less prone to leaching upon extracellular attacks. In addition, the photo-Fenton process either remained unchanged or lowered the antibiotic resistance threshold. Moreover, the homogeneous photo-Fenton system considerably lowered the detection of antibiotic resistance genes within 90 min with respect to hv, hv/H2O2, or heterogeneous photo-Fenton. In conclusion, the results suggest that the homogeneous photo-Fenton system could be an effective treatment for hindering the spread of antibiotic resistance, but treatment conditions should aim to maximize the degradation of ARG, as their concentration decreases more slowly than that of bacteria.

Assessment of bioimpedance spectroscopy devices: a comparative study and error analysis of gold-plated copper electrodes

Objective. Bioimpedance spectroscopy (BIS) is a non-invasive diagnostic tool to derive fluid volume compartments from frequency dependent voltage drops in alternating currents by extrapolating to the extracellular resistance (R 0) and intracellular resistance (R i). Here we tested whether a novel BIS device with reusable and adhesive single-use electrodes produces results which are (in various body positions) equivalent to an established system employing only single-use adhesive electrodes. Approach. Two BIS devices (‘Cella’ and the ‘Body Composition Monitor’ [BCM]) were compared using four dedicated resistance testboxes and by measuring 40 healthy volunteers. In vivo comparisons included supine wrist-to-ankle (WA) reference measurements and wrist-to-wrist (WW) measurements with pre-gelled silver/silver-chloride (Ag/AgCl) electrodes and WW measurements with reusable gold-plated copper electrodes. Main results. Coefficient of variation were <1% for all testbox measurements with both BIS devices. Accuracy was within ±1% of true resistance variability, a threshold which was only exceeded by the Cella device for all resistances in a testbox designed with a low R 0/R i ratio. In vivo, WA-BIS differed significantly between BIS devices (p < 0.001). Reusable WW electrodes exhibited larger resistances than WW-BIS with Ag/AgCl electrodes (R 0: 738.36 and 628.69 Ω; R i: 1508.18 and 1390 Ω) and the relative error varied from 7.6% to 31.1% (R 0) and −15.6% to 37.3% (R i). Significance. Both BIS devices produced equivalent resistances measurements but different estimates of body composition both in silico and in WA setups in vivo, suggesting that the devices should not be used interchangeably. Employing WW reusable electrodes as opposed to WA and WW measurement setups with pre-gelled Ag/AgCl electrodes seems to be associated with measurement variations that are too large for safe clinical use. We recommend further investigations of measurement errors originating from electrode material and current path.

Catalytic nanoreactors promote GLUT1-mediated BBB permeation by generating nitric oxide for potentiating glioblastoma ferroptosis

Glioblastoma, the most common malignant brain tumor with a poor prognosis, still needs to develop effective therapeutic strategies to prolong the patient’s survival. Inducing GBM tumor cell ferroptosis could be the specific assay to improve GBM therapeutic efficiency. In comparison, ferroptosis in GBM cells is limited by the low intracellular ferrous ion concentration and oxidation resistance. Herein, an MNP-based ferroptosis catalytic nanoreactor loading cisplatin (CMNP-Cis-Arg) was designed to evaluate their targeted delivery and therapeutic efficiency in GBM treatment. The ferroptosis catalytic nanoreactors achieved an effective GBM targeted transportation via chitosan oligosaccharide driven GLUT1-mediated BBB permeabilization and arginine-based tumor chemotactic. CMNP-Cis-Arg improves synergistically lipid oxidation in GBM cells by inducing ROS generation and depleting intracellular GSH. The MNPs elevate ROS levels in tumor cells by enhancing Fe2+-based Fenton reaction and the encapsulated cisplatin as a chemotherapy agent depleting GSH via inducing the DNA strand broken. Moreover, the CMNP-Cis-Arg further induces NO biosynthesis and generates ONOO– with high oxidability to increase lipid oxidation. The anti-GBM ability of the CMNP-Cis-Arg was evaluated both in vitro and in vivo, significantly inducing the GBM tumor cells’ apoptosis and reducing the tumor burden in an orthotopic mouse model. The investigation provided a novel ferroptosis catalytic nanoreactor and confirmed their anti-GBM efficiency in boosting tumor intracellular ferroptosis, suggesting a potential therapeutic strategy worth further investigating preclinically.

Effect of Low‐Temperature Stress on Electrical Impedance Spectroscopy Parameters of Rice Leaves at the Seedling Stage

The aim of this study was to detect the electrochemical characteristics of rice leaves under low‐temperature stress. This study uses the electrical impedance graph method and the electrolyte exostosis method under the condition of low‐temperature cold case study in the seedling stage of rice leaves, with a normal seedling stage of rice crops grown as controls. The shape of the electrical impedance map of rice leaves under low‐temperature stress and its change with the increase of low‐temperature stress were studied, and the change trend of electrical impedance map parameters with the increase of low‐temperature stress was statistically analyzed. At the same time, the two detection methods are discussed to establish the correlation. The results showed that the electrical impedance pattern was a complete, symmetrical, single half arc with rice leaves subjected to reversible damage. The left side of the arc starts to disappear with an irreversible injury. Rice tended to die when the arc on the right side of the impedance spectrum began to scatter. Moreover, the change in the electrical impedance spectrum was consistent with that of relative conductivity. When the rice was not dead, the extracellular resistance and relaxation time of leaves decreased with the increase of stress degree, and intracellular resistance increased. Indicating the electrical impedance spectroscopy (EIS) can be employed as a nondestructive testing method to detect physiological characteristics of rice leaves under low‐temperature stress.

Biochar induces different responses of intracellular and extracellular antibiotic resistance genes and suppresses horizontal transfer during lincomycin fermentation dregs composting

This study aims to indicate the influence of biochar on extracellular and intracellular ARGs (e/iARGs) variation and proliferation during lincomycin fermentation dregs (LFDs) compost. Biochar addition made iARGs keep reducing but eARGs increase to the maximum at the middle thermophilic phase and reduce at the end of the compost. Compared to control 3.15-log and 5.42-log reduction of iARGs and eARGs were observed, respectively. Biochar addition, bacterial community, and MGEs were the major contributors to iARGs and eARGs removal, with the contribution percentages of 38.4%, 31.0%, 23.7%, and 27.2%, 29.1%, and 34.9%, respectively. Moreover, biochar significantly inhibited eARGs transformation and RP4 plasmid conjugative transfer among E. coli DH5α and Pseudomonas aeruginosa HLS-6. The underlying mechanism involved in broken cell membranes of bacteria, and altered expression of oxidative stress genes and save our souls (SOS) response-related genes. The results indicated that biochar addition in composting could limit the dissemination of ARGs.