Excessive use of antibiotics will enter the water environment and soil through the biological chain, and then transfer to the human body through food, resulting in drug resistance, kidney toxicity and other health problems, so it is urgent to develop highly sensitive detection methods of antibiotics. Here, we designed a dual-mode sensor platform based on closed bipolar electrode (cBPE) electroluminescence (ECL) and mobile phone imaging to detect kanamycin in seawater. The prepared CN-NV-550 displayed extremely intense ECL signal, allowing for convenient mobile phone imaging. The cBPE was combined with DNA cycle amplification technology to prevent the mutual interference between target and the luminescent material, and realized the amplification of signal. In the presence of target Kana, Co3O4 was introduced to the cBPE anode by DNA cycle amplification product, and accelerated the oxidation rate of uric acid (UA). Thus, the electroluminescence response of CN-NV-550 on cBPE cathode was much improved due to the charge balance of the cBPE, achieving both ECL detection and mobile phone imaging assay of Kana, which much improved the accuracy and efficiency of assay. The limit of detection (LOD) in this work is 0.23 pM, and LOD for mobile phone imaging is 0.39 pM. This study integrate ECL imaging visualization of CN-NV-550 and high electrocatalytic activity of Co3O4 into cBPE-ECL detection, providing a new perspective for antibiotic analysis, and has great potential for practical applications, especially in Marine environmental pollution monitoring.

UNASSIGNED: Aminoglycoside-modifying enzymes (AMEs) play an essential role in bacterial resistance to aminoglycoside antimicrobials. With the development of sequencing techniques, more bacterial genomes have been sequenced, which has aided in the discovery of an increasing number of novel resistance mechanisms.
UNASSIGNED: The bacterial species was identified by 16S rRNA gene homology and average nucleotide identity (ANI) analyses. The minimum inhibitory concentration (MIC) of each antimicrobial was determined by the agar dilution method. The protein was expressed with the pCold I vector in E. coli BL21, and enzyme kinetic parameters were examined. The whole-genome sequence of the bacterium was obtained via the Illumina and PacBio sequencing platforms. Reconstruction of the phylogenetic tree, identification of conserved functional residues, and gene context analysis were performed using the corresponding bioinformatic techniques.
UNASSIGNED: A novel aminoglycoside resistance gene, designated aph(3\')-Ie, which confers resistance to ribostamycin, kanamycin, sisomicin and paromomycin, was identified in the chromosome of the animal bacterium Citrobacter gillenii DW61, which exhibited a multidrug resistance phenotype. APH(3\')-Ie showed the highest amino acid identity of 74.90% with the functionally characterized enzyme APH(3\')-Ia. Enzyme kinetics analysis demonstrated that it had phosphorylation activity toward four aminoglycoside substrates, exhibiting the highest affinity (K m, 4.22 ± 0.88 µM) and the highest catalytic efficiency [k cat/K m, (32.27 ± 8.14) × 104] for ribomycin. Similar to the other APH(3\') proteins, APH(3\')-Ie contained all the conserved functional sites of the APH family. The aph(3\')-Ie homologous genes were present in C. gillenii isolates from different sources, including some of clinical significance.
UNASSIGNED: In this work, a novel chromosomal aminoglycoside resistance gene, designated aph(3\')-Ie, conferring resistance to aminoglycoside antimicrobials, was identified in a rabbit isolate C. gillenii DW61. The elucidation of the novel resistance mechanism will aid in the effective treatment of infections caused by pathogens carrying such resistance genes.

Hearing loss is a major health concern in our society, affecting more than 400 million people worldwide. Among the causes, aminoglycoside therapy can result in permanent hearing loss in 40% to 60% of patients receiving treatment, and despite these high numbers, no drug for preventing or treating this type of hearing loss has yet been approved by the US Food and Drug Administration. We have previously conducted high-throughput screenings of bioactive compounds, using zebrafish as our discovery platform, and identified piplartine as a potential therapeutic molecule. In the present study, we expanded this work and characterized piplartine\'s physicochemical and therapeutic properties. We showed that piplartine had a wide therapeutic window and neither induced nephrotoxicity in vivo in zebrafish nor interfered with aminoglycoside antibacterial activity. In addition, a fluorescence-based assay demonstrated that piplartine did not inhibit cytochrome C activity in microsomes. Coadministration of piplartine protected from kanamycin-induced hair cell loss in zebrafish and protected hearing function, outer hair cells, and presynaptic ribbons in a mouse model of kanamycin ototoxicity. Last, we investigated piplartine\'s mechanism of action by phospho-omics, immunoblotting, immunohistochemistry, and molecular dynamics experiments. We found an up-regulation of AKT1 signaling in the cochleas of mice cotreated with piplartine. Piplartine treatment normalized kanamycin-induced up-regulation of TRPV1 expression and modulated the gating properties of this receptor. Because aminoglycoside entrance to the inner ear is, in part, mediated by TRPV1, these results suggested that by regulating TRPV1 expression, piplartine blocked aminoglycoside\'s entrance, thereby preventing the long-term deleterious effects of aminoglycoside accumulation in the inner ear compartment.

Rare earth (RE)-doped CaS phosphors have been widely used as light-emitting components in various fields. Nevertheless, the application of nanosized CaS particles is still significantly limited by their poor water resistance and weak luminescence. Herein, a lattice-matching strategy is developed by growing an inert shell of cubic NaYF4 phase on the CaS luminescent core. Due to their similarity in crystal structure, a uniform core-shell heterostructure (CaS:Ce3+@NaYF4) can be obtained, which effectively protects the CaS:Ce3+ core from degradation in aqueous environment and enhances its luminescence intensity. As a proof of concept, a label-free aptasensor is further constructed by combining core-shell CaS:Ce3+@NaYF4 and Au nanoparticles (AuNPs) for the ultrasensitive detection of kanamycin antibiotics. Based on the efficient FRET process, the detection linear range of kanamycin spans from 100 to 1000 nM with a detection limit of 7.8 nM. Besides, the aptasensor shows excellent selectivity towards kanamycin antibiotics, and has been successfully applied to the detection of kanamycin spiked in tap water and milk samples, demonstrating its high potential for sensing applications.

Indole serves as a signaling molecule that could regulate different bacterial physiological processes, including antibiotic resistance through biofilm formation and drug efflux pump activity. In Escherichia coli, indole is produced through the tryptophan pathway, which involves three permeases (Mtr, AroP, and TnaB) that can transport the amino acid tryptophan. Although these permeases play distinct roles in the secretion of indole biosynthesis, their impact on multidrug resistance mediated by indole remaines unclear. This study was designed to investigate the connection between the tryptophan transport system and antibiotic resistance by constructing seven gene deletion mutants from E. coli MG1655 (wild type). Our result showed that deletion of the aroP or tnaB gene led to increased antibiotic resistance as evaluated by MICs for different antibiotics. Efflux activity test results revealed that the increased antibiotic resistance was related with the AcrAB-Tolc drug efflux pump in the mutants. The transcriptome analysis further demonstrated that decreased susceptibility to kanamycin and ampicillin in E. coli was accompanied by reduced accumulation of reactive oxygen species and decreased motility. These findings highlight the substantial influence of the tryptophan transport system on antibiotic resistance in E. coli, which is crucial for developing strategies against antibiotic resistance in bacterial infections.

Herein, a new dual-model photoelectrochemical (PEC)/electrochemical (EC) sensor based on Z-scheme titanium dioxide (TiO2) disk/methylene blue (MB) sensibilization for the detection of kanamycin (Kana) was developed. Metal-organic framework-derived porous TiO2 disks were synthesized and exhibited excellent anodic photocurrent under visible light excitation. Subsequently, amino-labeled double-stranded DNA (dsDNA) was introduced into the modified electrode. Photocurrent was enhanced with MB embedded in dsDNA to form Z-scheme TiO2/MB sensibilization. When the target, Kana, was present, it specifically bound to the aptamer in the dsDNA, leading to the disruption of the dsDNA structure and the release of MB. This release of MB and the increase in target spatial resistance resulted in a significant weakening of PEC signal and a decreased oxidation peak current of MB. The PEC sensor successfully detected Kana in the range of 2-1000 pM with an LOD of 0.17 pM. Meanwhile, the EC sensor for Kana detection showed a linear range of 5-500 pM with an LOD of 1.8 pM. Additionally, the sensor exhibited excellent selectivity, reproducibility, stability, and good recoveries when applied to milk and honey samples. As a result, this method has the potential for application in ensuring food safety through the rapid determination of antibiotics in food.

BACKGROUND: Kanamycin (KAN) residues in animal-derived foods continuously enter the human body, which will pose serious threats to human health such as hearing loss, nephrotoxicity and other complications. Therefore, to sensitively detect KAN residues by a reliable technology is extremely urgent in food quality and safety. Compared with traditional methods being limited by cost and complexity, photoelectrochemical (PEC) biosensors benefit from some merits such as rapid response, excellent sensitivity and good stability. In this study, the construction of a highly efficient PEC platform to realize KAN residues detection is discussed.
RESULTS: Herein, a novel p-n heterojunction consisting of flower-like BiOI microspheres and graphite carbon nitride (g-C3N4) nanoflakes was developed to establish a PEC aptasensor for KAN detection at 0 V. The prepared g-C3N4/BiOI heterostructure showed not only significantly enhanced PEC activity due to the larger specific surface area but also greatly increased charge separation efficiency owing to the strong internal electric field. Meanwhile, using g-C3N4/BiOI as a highly efficient photoactive material for binding amine-functionalized aptamers to capture KAN, the photocurrent signals showed a \'turn off\' mode to achieve the sensitive detection of KAN. The proposed PEC aptasensor exhibited linear response for KAN from 5 × 10-9 to 3 × 10-7 mol L-1 with a low detection limit of 1.31 × 10-9 mol L-1, and satisfactory recoveries (97.44-107.38 %) were obtained in real food samples analysis.
CONCLUSIONS: This work presented a novel p-n heterojunction-based PEC aptasensor with strong selectivity and stability, rendering it allowed to detect KAN in animal-derived foods including milk, honey and pork. Additionally, the detection range satisfied the MRLs for KAN specified by the national standards, demonstrating the potential application for food analysis. The study provides a new insight into the development of efficient and practical biosensors for antibiotic residues detection.

UNASSIGNED: Pseudothrombocytopenia is a commonly obtained false negative result when analyzing feline platelet (PLT) count by an automated machine. It is related to ethylenediamine tetra-acetic acid (EDTA), a widely utilized anticoagulant in blood collection tubes, resulting in EDTA-dependent pseudothrombocytopenia (EDTA-PTCP).
UNASSIGNED: To investigate whether treated with kanamycin enhanced the quantity of PLT aggregations in feline blood specimens collected using EDTA-PTCP.
UNASSIGNED: Thirty-one blood samples were obtained using EDTA tubes. The complete blood count was analyzed using an automated Mindray BC-5000Vet. Both Manual cell counts and thin blood smears were performed to estimate the amount of red blood cell, white blood cell, and PLTs as well as to evaluate the severity scores of PLT clumping, respectively. Comparisons were made between those pre-treated and those treated with kanamycin in the EDTA tube.
UNASSIGNED: There were significantly different mean PLT counts in the samples before and after they were treated with kanamycin, both on automated (156.6 ± 76.4 vs. 260.3 ± 115.5; p < 0.001) and manual (168.5 ± 92.1 vs. 262.8 ± 119.6; p < 0.001) readings, with a 95% confidence interval of 0.19 (0.022-0.365).
UNASSIGNED: This study suggests that in clinical laboratory practice, kanamycin should be added to feline blood specimens with EDTA-PTCP.

Aminoglycosides are crucial antibiotics facing challenges from bacterial resistance. This study addresses the importance of aminoglycoside modifying enzymes in the context of escalating resistance. Drawing upon over two decades of structural data in the Protein Data Bank, we focused on two key antibiotics, neomycin B and kanamycin A, to explore how the aminoglycoside structure is exploited by this family of enzymes. A systematic comparison across diverse enzymes and the RNA A-site target identified common characteristics in the recognition mode, while assessing the adaptability of neomycin B and kanamycin A in various environments.

A Ti3C2Tx/MoS2/MWCNT@rGONR nanocomposite was prepared for the first time for building a sensitive electrochemical aptasening platform to simultaneously detect kanamycin (Kana) and chloramphenicol (Cap). Owing to their accordion-like structure, rich surface groups, and high charge mobility, Ti3C2Tx/MoS2/MWCNT@rGONR composites provided a spacious covalent immobilization surface and a better electrochemical aptasensing platform. The aptamers of Kana and Cap used in sensors enhance the selectivity. Furthermore, TiP, an ion exchanger, was used for loading more different metal ions functioning as labels to form a sandwich-type sensor together with Ti3C2Tx/MoS2/MWCNT@rGONR, improving the electrochemical sensitivity and obtaining a highly distinguishable signal readout. Under the optimized conditions, the sensor has good detection limits of 0.135 nmol L-1 and 0.173 nmol L-1 for Kana and Cap, respectively, at the same linearity concentration of 0.5-2500 nmol L-1. Finally, it was successfully applied for detection in milk and fish meat, and the results were compared with the standard method HPLC, indicating its great potential for food safety monitoring.