In-depth study of the components of polymyxins is the key to controlling the quality of this class of antibiotics. Similarities and variations of components present significant analytical challenges. A two-dimensional (2D) liquid chromatography-mass spectrometr (LC-MS) method was established for screening and comprehensive profiling of compositions of the antibiotic colistimethate sodium (CMS). A high concentration of phosphate buffer mobile phase was used in the first-dimensional LC system to get the components well separated. For efficient and high-accuracy screening of CMS, a targeted method based on a self-constructed high resolution (HR) mass spectrum database of CMS components was established. The database was built based on the commercial MassHunter Personal Compound Database and Library (PCDL) software and its accuracy of the compound matching result was verified with six known components before being applied to genuine sample screening. On this basis, the unknown peaks in the CMS chromatograms were deduced and assigned. The molecular formula, group composition, and origins of a total of 99 compounds, of which the combined area percentage accounted for more than 95% of CMS components, were deduced by this 2D-LC-MS method combined with the MassHunter PCDL. This profiling method was highly efficient and could distinguish hundreds of components within 3 h, providing reliable results for quality control of this kind of complex drugs.

Tropane alkaloids (TAs) are a class of anticholinergic drugs widely used in clinical practice and mainly extracted from plant, among which Atopa belladonna is the main commercial drug source. It is of great industrial value to obtain TAs in large quantities by plant metabolic engineering. In TAs pathway, cytochrome oxidase CYP82M3 catalyze the synthesis of tropinone and then tropinone reductase I (TRI) compete with TRII for tropinone to form tropine leading to the TAs synthesis (drainage). In this study, based on the "increasing flow and drainage" metabolic engineering strategy, two genes, namely HnCYP82M3 and DsTRI from Hyoscyamus niger and Datura stramonium, respectively, were overexpressed in the hair roots of A. belladonna, with a view to promote the TAs accumulation. The HnCYP82M3 gene was cloned from the root of H. niger, and it encoded amino acid with 91.7% sequence identity with AbCYP82M3 from A. belladonna. Overexpression of HnCYP82M3 alone did not affect the content of TAs in hair roots of A. belladonna, indicating that CYP82M3 was not a key enzyme in TAs biosynthesis. Simultaneous overexpression of HnCYP82M3 and DsTRI greatly promoted the accumulation of the three TAs, and the contents of hyoscyamine, anisodamine and scopolamine were 4.97 times, 2.83 times and 2.19 times that of the control, respectively, and the increase amplitude was greater than that of single overexpression of DsTRI. This study showed that the "increasing flow and drainage" strategy of enzyme genes co-expression at branch points was a promising metabolic engineering method to effectively improve the biosynthesis of TAs in A. belladonna, and laid a theoretical and technical foundation for the large-scale industrial acquisition of TAs.

Fluorescence microscopy is a vital tool in life science research, but the diffraction nature of light limits further observation of cells. Super-resolution imaging techniques provide deeper insights into cellular structures, including stimulated emission depletion microscopy (STED), structured illumination microscopy (SIM), and single-molecule localization microscopy (SMLM). Each of these methods offers unique advantages and principles that push the boundaries of spatial resolution beyond conventional diffraction limits. Among these techniques, SMLM stands out for its exceptional resolution, offering nanometer resolution and becoming a powerful tool for obtaining high-resolution images. SMLM is particularly valuable for studying the spatial distribution and interactions of organelles and macromolecular complexes. Following the award of the Nobel Prize in Chemistry in 2014, super-duper resolution imaging techniques were listed as one of Nature’s seven technologies to watch in 2024. The development of these techniques remains an important area of research. We introduce the development of multi-color SMLM, three-dimensional (3D) SMLM, and nanoscale resolution microscopes. We describe several methods to achieve multi-color SMLM. Sequential imaging and Exchange-PAINT require image targets in sequence, excitation or emission spectral demixing can obtain multi-color images simultaneously based on spectral difference between fluorescent dyes, dual-channel spectroscopic SMLM to achieve simultaneous imaging and spectral analysis of each molecule, and techniques based on binding kinetics of PAINT achieve multi-color by designing the blinking behavior of targets with engineered binding frequency and duration in DNA-PAINT. We then discuss various approaches for 3D imaging. Point spread function (PSF) engineering techniques manipulate the shape and properties of the PSF to improve 3D localization accuracy. Multi-plane imaging methods capture images from different focal planes and reconstruct them to obtain 3D information. Interferometry methods use single molecule interference to achieve high precision in axial localization, providing another way for high resolution 3D nanoscopy. Finally, we highlight advances in new nanoscale resolution microscopes based on modulated illumination patterns, including minimal photon fluxes (MINFLUX), repetitive optical selective exposure (ROSE), ROSE-Z, SIMFLUX, SIMPLE, and ModLoc. MINFLUX is known for its ability to achieve ultra-high resolution by detecting minimal photon fluxes from single molecules using a doughnut-shaped excitation spot to spatially modulate excitation intensities. Typically, we focus on ROSE and ROSE-Z, which outperform other techniques, using a resonant mirror to eliminate localization errors caused by fluorescence blinking. Recently, resolution enhancement by sequential imaging (RESI) and one nanometre expansion (ONE) was introduced to achieve resolution down to the Ångström scale. Nanoscopy serves as a new role between super resolution microscopy and structural biology and will lead to more discoveries in complex biological systems. Overall, this article provides a comprehensive overview of current advances in super-resolution imaging techniques, highlighting their contributions to overcoming the diffraction limit and enabling detailed observation of nanoscale biological structures, and provides an outlook on promising new techniques and applications. Through detailed descriptions of the principles, benefits, and applications of multi-color and 3D techniques, the article highlights new nanoscale imaging techniques that are expanding our ability to visualize and understand the intricate details of molecular and cellular processes. We hope that this article can be a primer resource for both newcomers and seasoned practitioners of SMLM.

OBJECTIVE: Arsenic (As) and fluoride (F) are two of the most common elements contaminating groundwater resources. A growing number of studies have found that As and F can cause neurotoxicity in infants and children, leading to cognitive, learning, and memory impairments. However, early biomarkers of learning and memory impairment induced by As and/or F remain unclear. In the present study, the mechanisms by which As and/or F cause learning memory impairment are explored at the multi-omics level (microbiome and metabolome). METHODS: We stablished an SD rats model exposed to arsenic and/or fluoride from intrauterine to adult period. RESULTS: Arsenic and/fluoride exposed groups showed reduced neurobehavioral performance and lesions in the hippocampal CA1 region. 16S rRNA gene sequencing revealed that As and/or F exposure significantly altered the composition and diversity of the gut microbiome，featuring the Lachnospiraceae_NK4A136_group, Ruminococcus_1, Prevotellaceae_NK3B31_group, [Eubacterium]_xylanophilum_group. Metabolome analysis showed that As and/or F-induced learning and memory impairment may be related to tryptophan, lipoic acid, glutamate, gamma-aminobutyric acidergic (GABAergic) synapse, and arachidonic acid (AA) metabolism. The gut microbiota, metabolites, and learning memory indicators were significantly correlated. CONCLUSION Learning memory impairment triggered by As and/or F exposure may be mediated by different gut microbes and their associated metabolites.
Rats ; Animals ; Arsenic/toxicity* ; Fluorides ; RNA, Ribosomal, 16S/genetics* ; Rats, Sprague-Dawley ; Metabolome ; Microbiota

OBJECTIVE: To compare the efficiency and effect of establishing rat peri-implantitis model by traditional cotton thread ligation and local injection of Porphyromonas gingivalis lipopolysaccharide (LPS) around the implant, as well as the combination of the two methods. METHODS: Left side maxillary first molars of 39 male SD rats were extracted, and titanium implants were implanted after four weeks of healing. After 4 weeks of implant osseointegration, 39 rats were randomly divided into 4 groups. Cotton thread ligation (n=12), local injection of LPS around the implant (n=12), and the two methods combined (n=12) were used to induce peri-implantitis, the rest 3 rats were untreated as control group. All procedures were conducted under 5% isoflurane inhalation anesthesia. The rats were sacrificed 2 weeks and 4 weeks after induction through carbon dioxide asphyxiation method. The maxilla of the rats in the test groups were collected and marginal bone loss was observed by micro-CT. The gingival tissues around the implants were collected for further real time quantitative PCR (RT-qPCR) analysis, specifically the expression of tumor necrosis factor-alpha (TNF-α) as well as interleukin-1β (IL-1β). The probing depth (PD), bleeding on probing (BOP) and gingival index (GI) of each rat in the experimental group were recorded before induction of inflammation and before death. RESULTS: After 4 weeks of implantation, the osseointegration of implants were confirmed. All the three test groups showed red and swollen gums, obvious marginal bone loss around implants. After 2 weeks and 4 weeks of inflammation induction, PD, GI and BOP of the three test groups increased compared with those before induction, but only BOP was statistically significant among the three test groups (P < 0.05). At the end of 2 weeks of inflammation induction, marginal bone loss was observed at each site in the cotton thread ligation group and the combined group. At each site, the bone resorption in the combined group was greater than that in the cotton thread ligation group, but the difference was not statistically significant (P > 0.05), bone resorption was observed at some sites of some implants in LPS local injection group. At the end of 4 weeks of inflammation induction, marginal bone loss was observed at all sites in each group. The marginal bone loss in the cotton thread ligation group and the combined group was greater than that in the LPS local injection group, and the difference was statistically significant (P < 0.05). At the end of 2 weeks and 4 weeks of induction, the expression of TNF-α and IL-1β in the test groups were higher than those in the control group (P < 0.05). CONCLUSION Compared with local injection of LPS around the implant, cotton thread ligature and the two methods combined can induce peri-implantitis in rats better and faster.
Animals ; Male ; Rats ; Alveolar Bone Loss/etiology* ; Dental Implants/adverse effects* ; Inflammation ; Lipopolysaccharides ; Peri-Implantitis/pathology* ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha

Drastic surges in intracellular reactive oxygen species (ROS) induce cell apoptosis, while most chemotherapy drugs lead to the accumulation of ROS. Here, we constructed an organic compound, arsenical N-‍(4-(1,3,2-dithiarsinan-2-yl)phenyl)acrylamide (AAZ2), which could prompt the ROS to trigger mitochondrial-dependent apoptosis in gastric cancer (GC). Mechanistically, by targeting pyruvate dehydrogenase kinase 1 (PDK1), AAZ2 caused metabolism alteration and the imbalance of redox homeostasis, followed by the inhibition of phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway and leading to the activation of B-cell lymphoma 2 (Bcl2)/Bcl2-associated X (Bax)/caspase-9 (Cas9)/Cas3 cascades. Importantly, our in vivo data demonstrated that AAZ2 could inhibit the growth of GC xenograft. Overall, our data suggested that AAZ2 could contribute to metabolic abnormalities, leading to mitochondrial-dependent apoptosis by targeting PDK1 in GC.
Humans ; Signal Transduction ; Stomach Neoplasms/drug therapy* ; Reactive Oxygen Species/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Apoptosis ; Proto-Oncogene Proteins c-bcl-2 ; Cell Line, Tumor

OBJECTIVE: To compare the predictive ability of two extended Cox models in nonlinear survival data analysis. METHODS: Through Monte Carlo simulation and empirical study and with the conventional Cox Proportional Hazards model and Random Survival Forests as the reference models, we compared restricted cubic spline Cox model (Cox_RCS) and DeepSurv neural network Cox model (Cox_DNN) for their prediction ability in nonlinear survival data analysis. Concordance index was used to evaluate the differentiation of the prediction results (a larger concordance index indicates a better prediction ability of the model). Integrated Brier Score was used to evaluate the calibration degree of the prediction (a smaller index indicates a better prediction ability). RESULTS: For data that met requirement of the proportion risk, the Cox_RCS model had the best prediction ability regardless of the sample size or deletion rate. For data that failed to meet the proportion risk, the prediction ability of Cox_DNN was optimal for a large sample size (≥500) with a low deletion (< 40%); the prediction ability of Cox_RCS was superior to those of other models in all other scenarios. For example data, the Cox_RCS model showed the best performance. CONCLUSION In analysis of nonlinear low maintenance data, Cox_RCS and Cox_DNN have their respective advantages and disadvantages in prediction. The conventional survival analysis methods are not inferior to machine learning or deep learning methods under certain conditions.
Proportional Hazards Models ; Survival Analysis ; Calibration ; Computer Simulation ; Data Analysis

Objective:To analyze the whole genome of Omicron variants causing the first local Omicron outbreak in Henan Province and to investigate the mutations in the SARS-CoV-2 genome for source tracing.Methods:Respiratory tract samples from COVID-19 cases in the Omicron outbreak in Henan Province from January 7 to 29, 2022 were subjected to whole-genome sequencing and sequence alignment analysis. Whole-genome identity, variations and evolution of the Omicron variants were analyzed.Results:Through high-throughput sequencing, the whole-genome sequences of SARS-CoV-2 were obtained from 120 cases, which accounted for 25.64% (120/468) of all COVID-19 cases in Anyang during the same period. Compared with the genome of Wuhan reference strain (NC_045512.2), there were 57-59 nucleotide mutation sites in the 120 whole genome sequences, and one or two nucleotide mutation sites were added to the shared 57 nucleotide sites. All of the 120 strains were VOC/Omicron (BA.1.1) variants and shared high homology. The whole-genome sequence obtained from the first case A contained 57 nucleotide mutation sites, while apart from the 57 identical nucleotide mutation sites, one specific mutation site (C1594T) was found in the whole-genome sequence obtained from the first case B, suggesting that the two cases were in the same transmission chain. After comparing with the database of domestic and imported cases by the Chinese Center for Disease Control and Prevention and the Henan Provincial Center for Disease Control and Prevention, it was found that the current outbreak was linked with the same transmission chain as the existing local epidemics in other provinces. Moreover, epidemiological investigation showed that on January 2, case A had come into contact with her cousin and his family who returned from an affected area outside the province.Conclusions:Based on the gene sequencing results and epidemiological investigation, the COVID-19 outbreak in Anyang city, Henan Province was a local epidemic and the source of it was a college student who returned to Anyang city from other province on December 28, 2021. These infections were linked to the same transmission chain as the existing local infection in other provinces.

The rol genes on pRiA4 plasmid of Agrobacterium rhizogenes are potent genes that promote secondary metabolism. Molecular breeding of Atropa belladonna can be conducted by introducing rol genes to increase tropane alkaloids (TAs) content in A. belladonna. In this study, the rolB gene was overexpressed in A. belladonna plants to study the effect of rolB gene on the biosynthesis of TAs. The phenotype, TAs content and expression levels of key enzyme genes in the pathway of TAs biosynthesis of transgenic A. belladonna were analyzed. The results showed that transgenic A. belladonna had developed root system, enlarged leaves, increased leaf fresh weight, deepened leaf color, enlarged flowers, changed flower shape, reduced pistil height and decreased pollen vitality. The content of TAs in the stems of transgenic A. belladonna was significantly higher than that of the control, and the contents of scopolamine, anisodamine, hyoscyamine can reach 2.11-2.91, 1.23-2.37 and 4.88-5.20 times of the control, respectively. Compared with the control group, the expressions of key enzymes putrescine N-methyltransferase (PMT), type III polyketide synthase (PYKS), tropinone reductase I (TRI), aromatic amino acid aminotransferase 4 (ArAT4), UDP-glycosyltransferase 1 (UGT1) and hyoscyamine 6-β-hydroxylase (H6H) in the TAs biosynthesis pathway were up-regulated, and the expression of tropinone reductase II (TRII) as a metabolic shunting gene was down-regulated. The results indicated that rolB gene enhanced TAs synthesis ability in roots and accumulation in stems of A. belladonna by enhancing metabolic flow of TAs synthesis pathway and weakening the metabolic shunt of competing pathway. This study laid a foundation for molecular breeding of A. belladonna with high-yield TAs content using rolB gene.