Emergence of colistin-resistant Stenotrophomonas maltophilia with high virulence in natural aquatic environments.

The presence of Stenotrophomonas maltophilia in aquatic environments poses great health risks to immunocompromised individuals because of its multidrug resistance and resultant high mortality. However, a significant gap exists in the isolation and understanding of colistin-resistant S. maltophilia in aquatic environments. In this study, nine colistin-resistant S. maltophilia strains isolated from natural lakes were explored, and their phylogenetic relationship, biofilm formation, virulence, and antibiotic resistance profiles and underlying genetic determinants were assessed. After genome analysis, besides known multi-locus sequence typing (MLST) of ST532, new assigned ST965 and ST966 which phylogenetically clustered into soil isolates were found firstly. All the isolates exhibited resistance to multiple antibiotics, including aminoglycosides, beta-lactams, tetracyclines, and even colistin, with the highest minimum inhibitory concentration (MIC) against colistin reaching 640 mg/L. Comparative genomic analysis revealed aph(3')-Iic, blaL1, tetT, phoP, mcr-3, arnA, pmrE, and efflux pump genes as the genetic determinants underlying this multidrug resistance. Notably, the biofilm-forming capacities of the newly discovered ST965 and ST966 isolates were significant stronger than those of the known ST532 isolates (p < 0.01), resulting in the death of over 50 % of the Galleria mellonella population within 1 day of injection. The ST965 isolates demonstrated the highest virulence against G. mellonella, followed by the ST966 isolates and ST532 isolates which was phylogenetically clustered with clinical isolates, indicating that the novel S. maltophilia strains of ST965 and ST966 may pose considerable health risks to humans. Our findings provide insights into colistin-resistant S. maltophilia in aquatic environments and raise concerns about the health risks posed by the newly assigned sequence types of colistin-resistant S. maltophilia with potential high virulence in natural aquatic environments.

Clinical and histopathological factors for recurrence and metastasis in lacrimal gland adenoid cystic carcinoma in Chinese patients.

PURPOSE: To investigate the association of metabolism-related proteins and clinicopathological features with poor prognosis in lacrimal gland adenoid cystic carcinoma (LGACC). METHODS: Clinicopathological data for 39 Chinese patients with LGACC enrolled were retrospectively analysed. Disease progression included death, recurrence, further nodal metastasis, and distant metastasis. Expression of ASCT2 and GLS1 were evaluated by immunohistochemistry. Kaplan-Meier survival curves and Cox proportional hazards regression models were used for risk factor analyses. RESULTS: At the end of follow-up, 14 patients (35.9%) developed local recurrence, 13 patients (33.3%) developed distant metastasis, 3 patients (7.7%) developed lymph node metastasis, and 9 patients (23.1%) died. Among the 13 patients who developed distant metastasis, lung metastasis was observed in 8 patients (61.5%), the brain in 8 patients (61.5%), and bone in 1 patient (7.7%). ASCT2 was expressed in 16 (57.14%) cases, while GLS1 had high expression in 19 (67.9%) cases. Advanced T category (≥T3), bone erosion, basaloid subtype, and ASCT2 (-) were associated with disease progression. Basaloid subtype was an independent risk factor for local recurrence (P = 0.028; HR, 12.12; 95% CI, 1.3-111.5). ASCT2(-) was an independent risk factor for distant metastasis (P = 0.016; HR, 14.46; 95% CI, 1.6-127.5) and was associated with basaloid subtype (P = 0.019). CONCLUSIONS: For LGACC, ≥T3 category, basaloid subtype, and bone erosion were high-risk predictors. ASCT2(-) was an independent risk factor for distant metastasis, which suggested that it could be a potential biomarker for LGACC.

A Review of Microsphere Super-Resolution Imaging Techniques.

Conventional optical microscopes are only able to resolve objects down to a size of approximately 200 nm due to optical diffraction limits. The rapid development of nanotechnology has increased the demand for greater imaging resolution, with a need to break through those diffraction limits. Among super-resolution techniques, microsphere imaging has emerged as a strong contender, offering low cost, simple operation, and high resolution, especially in the fields of nanodevices, biomedicine, and semiconductors. However, this technology is still in its infancy, with an inadequate understanding of the underlying principles and the technology's limited field of view. This paper comprehensively summarizes the status of current research, the advantages and disadvantages of the basic principles and methods of microsphere imaging, the materials and preparation processes, microsphere manipulation methods, and applications. The paper also summarizes future development trends.

Landscape of antibiotic resistance genes and bacterial communities in groundwater on the Tibetan Plateau, and distinguishing their difference with low-altitude counterparts.

Groundwater is a vital source of drinking water for Tibetans. Antibiotic resistance genes (ARGs) and bacterial communities in groundwater on the Tibetan Plateau remain unclear. Furthermore, the characterization of their differences between high-altitude and low-altitude groundwater is still unrevealed. Herein, 32 groundwater samples were collected on the plateau, and intra- and extracellular ARGs (iARGs and eARGs), and bacterial communities were characterised through qPCR assays to 19 ARGs and 16S rRNA sequencing. It showed top four abundant intra- and extracellular last-resort ARGs (LARGs) were blaOXA-48, mcr-1, vanA, and vanB, whereas dominant common ARGs (CARGs) were tetA and ermB, respectively. CARGs had higher abundances than LARGs, and iARGs were more frequently detected than eARGs. Proteobacteria, an invasive resident phylum, and Firmicutes dominated eDNA release. Network analysis revealed all observed LARGs co-occurred with pathogenic and non-pathogenic bacteria. Community diversity was significantly associated with longitude and elevation, while nitrate correlated with ARGs. Comparative analysis demonstrated eARG frequencies and abundances were higher at high altitudes than at low altitudes. Additionally, Acinetobacter and Pseudomonas specifically dominated at high altitudes. This study reveals the widespread prevalence of ARGs, particularly LARGs, in groundwater on the less-disturbed Tibetan Plateau and underlines the potential risks associated with the LARG-carrying bacteria. ENVIRONMENTAL IMPLICATION: Antibiotic resistance genes (ARGs), which are defined as emerging environmental contaminants, are becoming a global concern due to their ability to confer antibiotic resistance to pathogens. Our findings highlight the prevalence of ARGs, particularly LARGs, in groundwater on the Tibetan Plateau, and the possibility that naturally-occurring pathogenic and non-pathogenic bacteria carry multiple LARGs. In addition, we further reveal differences in the distribution of ARGs and bacterial community between high-altitude and low-altitude groundwater. Collectively, our findings offer an important insight into the potential public risks related to groundwater on the Tibetan Plateau.

Deep learning-based fully automated differential diagnosis of eyelid basal cell and sebaceous carcinoma using whole slide images.

Background: The differential diagnosis of eyelid basal cell carcinoma (BCC) and sebaceous carcinoma (SC) is highly dependent on pathologist's experience. Herein, we proposed a fully automated differential diagnostic method, which used deep learning (DL) to accurately classify eyelid BCC and SC based on whole slide images (WSIs). Methods: We used 116 haematoxylin and eosin (H&E)-stained sections from 116 eyelid BCC patients and 180 H&E-stained sections from 129 eyelid SC patients treated at the Shanghai Ninth People's Hospital from 2017 to 2019. The method comprises two stages: patch prediction by the DenseNet-161 architecture-based DL model and WSI differentiation by an average-probability strategy-based integration module, and its differential performance was assessed by the carcinoma differentiation accuracy and F1 score. We compared the classification performance of the method with that of three pathologists, two junior and one senior. To validate the auxiliary value of the method, we compared the pathologists' BCC and SC classification with and without the assistance of our proposed method. Results: Our proposed method achieved an accuracy of 0.983, significantly higher than that of the three pathologists (0.644 and 0.729 for the two junior pathologists and 0.831 for the senior pathologist). With the method's assistance, the pathologists' accuracy increased significantly (P<0.05), by 28.8% and 15.2%, respectively, for the two junior pathologists and by 11.8% for the senior pathologist. Conclusions: Our proposed method accurately classifies eyelid BCC and SC and effectively improves the diagnostic accuracy of pathologists. It may therefore facilitate the development of appropriate and timely therapeutic plans.

Degradation and adsorption behavior of biodegradable plastic PLA under conventional weathering conditions.

With the increasing pollution of plastics and the widespread use of polylactic acid (PLA), its weathering process in the natural environment needs to be studied. Hence, we investigated the characteristics of PLA under conventional weathering conditions and the adsorption behavior between PLA and tetracycline (TC). The results showed cracks and holes in the weathered PLA surface, an increase in oxygen-containing functional groups, and a 77.94 % decrease in contact angle, causing more amount of TC to be adsorbed. The maximum adsorption capacity of PLA for TC is approximately 3.5 times higher than before weathering due to multilayer physical adsorption. Nevertheless, the surface of the microplastics weathered by seawater did not change significantly. This work elucidates the weathering mechanism of biodegradable microplastics under abiotic conditions, thus correctly assessing the difference in natural and conventional degradability of biodegradable plastics.

Comprehensive insights into profiles and bacterial sources of intracellular and extracellular antibiotic resistance genes in groundwater.

Antibiotic resistance genes (ARGs), especially last-resort ARGs (LARGs), are receiving extensive attention as emerging environmental contaminants in groundwater. However, their prevalent intracellular and extracellular patterns and bacterial sources in groundwater remain unclear. Herein, groundwater samples were collected in Tianjin, and characterized based on the profiles of intracellular ARGs (iARGs) and extracellular ARGs (eARGs), as well as the resident bacterial communities and extracellular DNA (eDNA)-releasing bacterial communities. The quantitative real-time PCR assays showed that eARGs presented fewer subtypes than iARGs and generally displayed lower detection frequencies than the corresponding iARGs. Similarly, LARGs exhibited lower detection frequencies than common ARGs, but the total abundance showed no significant differences between them. Genes vanA and blaVIM were the observed dominant LARGs, and aadA was the observed common ARG independent of location inside or outside the bacteria. Furthermore, the top 10 phyla showed much difference between the main eDNA-releasing bacteria and the dominant resident bacteria. Proteobacteria was the predominant resident bacterial phyla while dominating the source of eDNA in groundwater. Despite representing a minor portion of the abundance in the resident bacteria, Actinobacteriota, Acidobacteriota, and Chloroflex surprisingly accounted for a large majority of eDNA release. Co-occurrence patterns among persistent ARGs, the resident bacteria, and eDNA-releasing bacteria revealed that the dominant common iARG aadA and intracellular LARGs blaVIM and vanA had significant positive correlations with Methylobacterium_Methylorubrum and Shewanella. Meanwhile, the dominant extracellular LARG blaVIM may be released by bacteria belonging to at least five genera, including Ellin6067, Bifidobacterium, Blautia, Veillonella, and Dechloromonas. Collectively, the findings of this study extend our understanding regarding the distribution of ARGs and their bacterial sources in groundwater, and indicate the serious pollution of LARGs in groundwater, which poses potential risks to public health.

Spatial behavior and source tracking of extracellular antibiotic resistance genes in a chlorinated drinking water distribution system.

Antibiotic resistance genes (ARGs) are receiving increasing concerns due to the antibiotic resistance crisis. Nevertheless, little is known about the spatial behavior and sources of extracellular ARGs (eARGs) in the chlorinated drinking water distribution systems (DWDSs). Here, tap water was continuously collected to reveal the occurrence of both eARGs and intracellular ARGs (iARGs) along a chlorinated DWDS. Afterward, the correlation between eARGs, eDNA-releasing communities, and communities of planktonic bacteria was further analyzed. The eARG concentration decreased significantly, whereas the proportion of vanA and blaNDM-1 increased. Further, the diversity of the eDNA-releasing community increased markedly with increasing distance from the drinking water treatment plant (DWTP). Moreover, the dominant eDNA-releasing bacteria shifted from Acinetobacter, Pseudomonas, and Methylobacterium-Methylorubrum in finished water from the DWTP to Bacteroides, Faecalibacterium, Staphylococcus, and Parabacteroides in the DWDS. In terms of eARG source, thirty genera were significantly correlated with seven types of eARGs that resulted from the lysis of dead planktonic bacteria and detached biofilms. Conversely, the iARGs concentration increased, whereas the biodiversity of the planktonic bacteria community decreased in the sampling points along the DWDSs. Our findings provide critical insights into the spatial behavior and sources of eARGs, highlighting the health risks associated with ARGs in DWDSs.

Mitochondria-targeted tetrahedral DNA nanostructures for doxorubicin delivery and enhancement of apoptosis.

Mitochondria-targeted nanoparticles, such as liposomes, polymers and inorganic particles, suffer from heterogeneity, low biocompatibility and low drug loading efficiency. Here, we present a novel delivery platform based on tetrahedral DNA nanostructures (TDNs) that enable the mitochondrial transportation of the anticancer drug doxorubicin (DOX) for cancer therapy. In our design, DOX was intercalated into TDNs, which executed the cell-killing function inside the tumor cells. Various numbers of d-(KLAKLAK)2 (KLA) were conjugated to TDNs to achieve the mitochondria targeting effect. The mean size of the KLA-modified TDNs was about 15 nm, and the TDNs were stable in FBS. The DOX loading efficiency of the TDNs was up to around 77%. The 3KLA-modified TDNs exhibited the most efficient DOX accumulation in mitochondria, leading to an effective release of cytochrome c, and the upregulated expression levels of caspase-9, caspase-3, p21 and p53. Meanwhile, 3KLA-TDNs/DOX elevated the pro-apoptotic Bax, reduced the anti-apoptotic Bcl-2 protein expression and increased the Bax/Bcl-2 ratio, which finally activated the mitochondria-mediated, programmed apoptosis pathway to enhance the anticancer efficacy in vitro. This 3KLA-TDN and DOX co-assembling strategy can be further developed to transport other anthracyclines and chemotherapeutic agents for enhanced apoptosis effects.

Polymeric nanoparticles responsive to intracellular ROS for anticancer drug delivery.

Thioketal and thioether are moieties used to fabricate reactive oxygen species (ROS)-responsive polymers for drug delivery. In this paper, three amphiphilic copolymers of mPEG-poly(ester-thioether), mPEG-poly(thioketal-ester) and mPEG-poly(thioketal-ester-thioether) were synthesized. The ROS-responsive behaviors of the three copolymers nanoparticles as drug carriers were investigated. The ROS-sensitivity was demonstrated by NMR, DLS, and SEM. mPEG-poly(ester-thioether) nanoparticles exhibited the fastest drug release rate, which possessed the best ROS sensitivity. The in vitro anticancer activity of the DOX-loaded nanoparticles was studied, the results revealed that the mPEG-poly(ester-thioether) nanoparticles showed the most efficient anticancer activity. Notably, all the three ROS-responsive copolymers nanoparticles showed enhanced cellular uptake and anticancer efficacy comparing to the control mPEG-b-PCL nanoparticles.

A reactive oxygen species-responsive prodrug micelle with efficient cellular uptake and excellent bioavailability.

Stimuli-responsive polymeric drug delivery systems are of great interest in anticancer research. Here, a reactive oxygen species (ROS)-responsive prodrug was prepared by thioketal linkage of poly(ethylene glycol) (PEG) and the anticancer drug doxorubicin (DOX). The ROS-responsive property of the prodrug was confirmed by dynamic light scattering and 1H NMR. The prodrug was then used as a drug carrier to further load DOX, to form a DOX-loaded prodrug micelle, which showed dual ROS and pH-responsive release behaviors. The prodrug micelle exhibited rapid intracellular uptake. Interestingly, the in vitro anticancer activity of the ROS-responsive prodrug micelle was better than that of the DOX-loaded prodrug micelle because of its faster cellular uptake and better bioavailability. However, both the ROS-responsive prodrug and drug-loaded prodrug micelles showed better anticancer efficacy than a non-responsive DOX-loaded poly(ethylene glycol)-block-polycaprolactone (PEG2k-PCL5k) micelle. Consistent results were obtained in in vivo animal experiments as the antitumor efficacy of the prodrug micelle was superior to that of the DOX-loaded prodrug micelle. Both micelles showed negligible systemic toxicity in vivo.

Redox/ATP switchable theranostic nanoparticles for real-time fluorescence monitoring of doxorubicin delivery.

In this study, redox/ATP switchable theranostic nanoparticles (TNs) with precise specificity and controllable mobility were developed for the real-time monitoring of the release of an anticancer drug. A fluorescent probe (FAM) and a quencher (BHQ-1) were covalently conjugated to one end of an adenosine-5'-triphosphate (ATP) aptamer and its complementary DNA (cDNA), respectively. Then, doxorubicin (DOX) was intercalated within the DNA duplex to form a stable physical conjugate (FBA@DOX). Poly(ethylene glycol)-block-poly (aspartic acid-graft-cystamine) (PAS), a glutathione-sensitive cationic polymer, was synthesized and complexed with the FBA@DOX, endowing it with excellent stability in physiological solutions. Fluorescence recovery/quenching, DNase degradation, in vitro drug release, cellular uptake, and intracellular trafficking results revealed that the TNs remained in the "OFF" state, with a minimal FAM fluorescent signal and negligible DOX premature release, in low-glutathione and/or low-ATP environments. In contrast, the TNs turned "ON" and rapidly released FBA@DOX in glutathione-rich environments after internalization in cancer cells. The intracellular ATP triggered the conformational changes in FBA@DOX, thereby enabling the controlled release of DOX and simultaneous recovery of the fluorescence for monitoring the DOX release. In a cytotoxicity and apoptosis study, the redox/ATP switchable TNs demonstrated strong anticancer effects, attributable to their selective release of the drug. Overall, our findings may offer a promising strategy for developing a new generation of "smart" theranostic platforms.

A reactive oxygen species (ROS)-responsive low molecular weight gel co-loaded with doxorubicin and Zn(ii) phthalocyanine tetrasulfonic acid for combined chemo-photodynamic therapy.

Low molecular weight gels (LMWGs) have significant advantages in drug delivery such as high drug loading capacity, in situ delivery of drug to the lesion site, sustaining drug release with excellent bioavailability, and minimized side effects. Here, we synthesized a reactive oxygen species (ROS)-responsive gelator to prepare an injectable gel. An anticancer drug, doxorubicin hydrochloride (DOX), and a photosensitizer, Zn(ii) phthalocyanine tetrasulfonic acid (ZnPCS4), were loaded into the gel for combined chemo-photodynamic therapy. The ROS-responsive gelator was characterized by proton nuclear magnetic resonance (1H NMR) and the morphology of gels was investigated by scanning electron microscopy (SEM). The rheological properties and destruction-recovery capability of both blank and drug-loaded gels were studied. The cytotoxicity of LMWGs against 3T3 fibroblasts and 4T1 breast cancer cells was tested. The in vitro drug release of both drugs was studied and the in vivo anticancer activities of DOX-ZnPCS4-coloaded LMWGs were investigated in tumor-bearing mice. The results revealed that the injectable ROS-responsive DOX-ZnPCS4-coloaded LMWGs exhibited excellent anti-tumor efficacy by a synergistic therapy.

Stability-indicating HPLC method development and structural elucidation of novel degradation products in posaconazole injection by LC-TOF/MS, LC-MS/MS and NMR.

Stress testing was carried out under acidic, alkaline, oxidative, thermal and photolytic conditions to evaluate the intrinsic stability of posaconazole injection. A total of four degradation products were detected and the drug was found to be susceptible to oxidative and thermal degradations. Three unknown degradants formed under oxidative stress condition were isolated by preparative HPLC and unambiguously elucidated by LC-TOF/MS, LC-MS/MS, (1)H NMR, (13)C NMR and 2D NMR techniques. Based on the spectrometric and spectroscopic information, these novel degradation products were unequivocally assigned as the N-oxides of posaconazole. Probable mechanisms for the formation of the degradants were proposed. A new and selective HPLC method was developed and validated to separate, detect and quantify all the degradants in posaconazole injection.