Objective To study the effect of microwave irradiation on a marine mutant strain B1 which had high antifungal activity,and obtain the optimum dosage of microwave irradiation.Methods The marine strain B1(Bacillus sp.) was radiated by 2450 MHz microwave for various times.The mutation rate p,mutation mean ? and the mutation variance ?~(2) were estimated by statistical methods.From these mutants,a high-activity strain B1-413 was obtained,and its genetic attribute was tested.Results Microwave irradiation was highly effective at 60 s.The MIC of mutant strain B1-413 was reduced from 125?l?mL~(-1)to 32?l? mL~(-1) compared with B1,the genetic attribute of which was stable through four generation cultivation.Conclusion The B1 was sensitive to microwave irradiation,and the higher anti-fungi active mutants can be easy obtained after the treatment of microwave irradiation.

A fast atom bombardment mass spectrometric method to predict and detect the antioxidant ability of phenolic compounds was developed to accelerate the pace of finding the antioxidant with higher effect and low toxicity. The effect of experimental conditions on the relative peak intensity ratio of M+· ion to [ M+H]+ion in the FAB mass spectra of the compound was investigated, including matrix, scan time and concentration. The correlation of antioxidant activity with the I ( M+· )/I ( [ M+H ]+) value of flavonoids obtained in FAB mass spectra was studied. Then the antioxidant activity of 12 phenolic compounds was predicted using the above method and the results were compared with those obtained from thiobarbituric acid ( TBA) method. The results show that the I( M+· )/I( [ M+H]+) value of the phenolic compound obtained from FAB mass spectra could reflect their antioxidant activity, which could help to accelerate the development of the antioxidant drug.

Objective To identify an suspected Vibrio cholerae isolated from Xiangyang Central Hospital and characterize the strain in terms of antibiotic resistance and relevant virulence genes.Methods Pathogen identification and susceptibility testing were completed with MicroScan WalkAway 40 Automated Microbiology System.Slide agglutination was used for serotyping. PCR and sequencing technology were employed for 16s RNA gene analysis.PCR technique was used to detect six major viru-lence genes.Results This suspectedVibrio cholerae isolate was confirmed as non-O1 and non-O139 Vibrio cholerae .Suscep-tibility testing results indicated that the strain was sensitive to ampicillin,chloramphenicol,trimethoprim-sulfamethoxazole, and tetracycline.16s RNA gene sequence analysis showed 100% homologous with the registered sequence in National Center for Biotechnology Information database.Virulence genes rtxC and toxR were identified.The other virulence genes such as tcpAET,ctxA,hlyA,and tcpACL were negative.Conclusions This suspected Vibrio cholerae isolate is confirmed as non-O1 and non-O139 Vibrio cholerae .The pathogenic factors may be related to the virulence genes rtxC and toxR.

To screen the harmful substance 5-hydroxymethyl furfural content in commercially available traditional Chinese medicine injection which are commonly used, and to preliminarily evaluate the quality of these injections, 5-hydroxymethyl furfural was taken as an index. The contents of 5-hydroxymethyl furfural in 56 samples which consist of 23 kinds of traditional Chinese medicine injections and glucose injection were determined using LC-MS/MS, and 5-hydroxymethyl furfural was detected in 52 of these samples. The minimal content was 0.0038 microg x L(-1) and the maximum content was 1420 microg x mL(-1). The contents of 5-hydroxymethyl furfural were significantly different in traditional Chinese medicine injection which came from different kinds, manufacturers or batches. The results showed the quality difference of commercially available traditional Chinese medicine injection is significant taking 5-hydroxymethyl furfural content as assessment index. More attention should be paid to the safety of 5-hydroxymethyl furfural in traditional Chinese medicine injection, and unified limitation standard should be set to improve medication safety of traditional Chinese medicine injection.

Three-dimensional(3D)cell spheroid models combined with mass spectrometry imaging(MSI)enables innovative investigation of in vivo-like biological processes under different physiological and patho-logical conditions.Herein,airflow-assisted desorption electrospray ionization-MSI(AFADESI-MSI)was coupled with 3D HepG2 spheroids to assess the metabolism and hepatotoxicity of amiodarone(AMI).High-coverage imaging of＞1100 endogenous metabolites in hepatocyte spheroids was achieved using AFADESI-MSI.Following AMI treatment at different times,15 metabolites of AMI involved in N-desethylation,hydroxylation,deiodination,and desaturation metabolic reactions were identified,and according to their spatiotemporal dynamics features,the metabolic pathways of AMI were proposed.Subsequently,the temporal and spatial changes in metabolic disturbance within spheroids caused by drug exposure were obtained via metabolomic analysis.The main dysregulated metabolic pathways included arachidonic acid and glycerophospholipid metabolism,providing considerable evidence for the mechanism of AMI hepatotoxicity.In addition,a biomarker group of eight fatty acids was selected that provided improved indication of cell viability and could characterize the hepatotoxicity of AMI.The combination of AFADESI-MSI and HepG2 spheroids can simultaneously obtain spatiotemporal infor-mation for drugs,drug metabolites,and endogenous metabolites after AMI treatment,providing an effective tool for in vitro drug hepatotoxicity evaluation.

Ansamycins, such as rifamycin and ansamitocin, usually consist of a group of structural similar components. Geldanamycin, a benzenic ansamycin, has been found to consist of four structural similar components. We analyzed the geldanamycin (GDM) preparation from Streptomyces hygroscopicus 17997 by LC-ESI(+)-MS/MS, and discovered five novel and one known GDM analogues in trace amounts. Based on the ESI(+)-MS/MS spectra of these GDM analogues, and the present understanding of GDM biosynthesis, we proposed the possible chemical structures of these GDM analogues. Three novel GDM analogues, all having the same molecular formula of C29H42N2O10, were GDM biosynthetic derivatives with one of the three C-C double bonds between C2-C3, C4-C5 and C8-C9 in GDM changed to mono-hydroxylated C-C single bond. The other two novel GDM analogues, having the same molecular formula of C28H38N2O8, were 17(or 12, or 4)-desmethoxylgeldanamycin and 4,5-dihydro-10,11-dehydrate-17-desmethyl-17-hydroxylgeldanamycin, respectively. The known GDM analogue, having the molecular formula of C29H42N2O9, was 4, 5-dihydrogeldanamycin, an intermediate in GDM biosynthesis. The discovery of novel GDM analogues provided us new insights in understanding the biosynthetic details of GDM, and clues of obtaining GDM derivatives by gene-disruption and combinatorial biosynthesis.
Anti-Bacterial Agents ; chemistry ; Benzoquinones ; analysis ; chemistry ; Chromatography, Liquid ; methods ; Lactams, Macrocyclic ; analysis ; chemistry ; Tandem Mass Spectrometry ; methods

Objective To explore the effectiveness of virtual autopsy-based postmortem computed tomography(PMCT)liver three dimensional slicer(3D slicer)artificial intelligence(AI)volume reconstruction to assist forensic practice.Methods Twenty cases of the deceased who underwent both virtual autopsy and traditional autopsy in our center were selected and subjected to liver volume segmentation by 3D slicer method,Tada's formula method and literature method,and the data obtained from the traditional autopsy were compared and analyzed to obtain the accuracy rate.Results The 3D slicer method yielded higher consistency(95%confidence interval),lower volumetric variability(standard deviation),and a smaller region(variance)of uncertainty than the Tada formula method and the methods mentioned in the literature.Conclusion 3D slicer AI reconstruction based on virtual autopsy can visualize virtual anatomy,help increase the diagnostic accuracy of traditional autopsy,assist in pathological diagnosis,and provide new directions and tools for the development of imaging histology of virtual autopsy.

Objective:To compare the accuracy of different stone scoring systems for predicting the stone-free rate (SFR) after retrograde intrarenal surgery (RIRS).Methods:The clinical data of 227 patients with lithiasis undergoing RIRS from June 2017 to December 2020 in Affiliated Benq Hospital of Nanjing Medical University and Qingdao Fuwai Hospital were retrospectively analyzed. There were 152 males and 75 females. The average age was (53.0±10.4) years old. The average body mass index was (26.9±2.1)kg/m 2. The maximum diameter of the stone was (22.7±12.8)mm. The stone is located in left side in 133 cases and in right side in 94 cases. The stones of 44 cases were located in upper ureter, upper calyceal or renal pelvis, that of 23 cases were in medium calyceal, 157 cases in lower calyceal, and 3 cases in calyceal diverticulum.The average CT value of stone was (778.3±350.4)HU. American Society of Anesthesiology (ASA)scores: 86 cases of grade Ⅰ, 129 cases of grade Ⅱ, 12 cases of grade Ⅲ. Preoperative non-contrast CT was conducted and three-dimensional data were constructed. A single observer reviewed and entered the modified S.T.O.N.E., RUSS, modified S-ReSC, R. I.R.S., SHA.LIN, Ito nomogram, S. O.L.V.E., stone free index (SFI) scores. Logistic analysis were performed between every score and SFR. Receiver operating characteristic (ROC) curve was drawn to detect sensitivity and specificity of every score in predicting the SFR. The predictive accuracies of all scores were compared. Results:The SFR was 83.0%(189/227). There were statistically significant differences in modified S. T.O.N.E.(10.5±1.9 vs. 12.7±1.8), RUSS[1(0, 4) vs. 3(0, 6)], modified S-ReSC (8.2±5.6 vs. 11.8±6.0), R.I.R.S.(6.2±1.4 vs. 8.1±1.2), SHA.LIN (9.9±2.4 vs. 13.0±2.1), Ito nomogram (12.1±5.8 vs. 4.3±3.3), S. O.L.V.E. (6.8±1.6 vs. 8.7±1.2), SFI score (7.9±1.1 vs. 6.3±0.9) between the stone-free group and the stone remaining group ( P <0.05). Logistic regression revealed that modified S.T.O.N.E., RUSS, modified S-ReSC, R. I.R.S., SHA.LIN, Ito nomogram, S. O.L.V.E. and SFI score were significantly associated with SFR( P<0.05). There were no significant differences in the area under the curve (AUC) between the modified S. T.O.N.E., RUSS, R. I.R.S., SHA.LIN, Ito nomogram, S. O.L.V.E. and SFI score( P>0.05), but there were significant differences in the AUC between modified S-ReSC score and other score ( P<0.05). When the cutoff of SHA.LIN, SFI and R. I.R.S. score was determined as 10, 6 and 6 scores, the specificity of SHA.LIN, SFI and R. I.R.S. score was 94.7%, 92.6% and 89.5%, respectively. Conclusions:All score could predict the postoperative SFR of RIRS, while the SHA.LIN, SFI and R.I.R.S. score were more accurate than the other scores. The accuracy of the modified S-ReSC in predicting SFR after RIRS was slightly worse than other scores.

Against tumor-dependent metabolic vulnerability is an attractive strategy for tumor-targeted therapy.However,metabolic inhibitors are limited by the drug resistance of cancerous cells due to their metabolic plasticity and heterogeneity.Herein,choline metabolism was discovered by spatially resolved metab-olomics analysis as metabolic vulnerability which is highly active in different cancer types,and a choline-modified strategy for small molecule-drug conjugates(SMDCs)design was developed to fool tumor cells into indiscriminately taking in choline-modified chemotherapy drugs for targeted cancer therapy,instead of directly inhibiting choline metabolism.As a proof-of-concept,choline-modified SMDCs were designed,screened,and investigated for their druggability in vitro and in vivo.This strategy improved tumor targeting,preserved tumor inhibition and reduced toxicity of paclitaxel,through targeted drug delivery to tumor by highly expressed choline transporters,and site-specific release by carboxylesterase.This study expands the strategy of targeting metabolic vulnerability and provides new ideas of devel-oping SMDCs for precise cancer therapy.

With the rapid development and wide application of traditional Chinese medicine injection (TCMI), a number of adverse events of some TCMIs have incessantly been reported and have drawn broad attention in recent years. Establishing effective and practical analytical methods for safety evaluation and quality control of TCMI can help to improve the safety of TCMIs in clinical applications. In this study, a sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method has been developed and validated for the quantitative determination of potentially harmful substance 5,5'-oxydimethylenebis (2-furfural, OMBF) in TCMI samples. Chromatographic separation was performed on a C18 reversed-phase column (150 mm × 2.1 mm, 5 µm) by gradient elution, using methanol-water containing 0.1% formic acid as mobile phase at the flow rate of 0.3 mL/min. MS/MS detection was performed on a triple quadrupole mass spectrometer with positive electrospray ionization in the multiple reaction-monitoring mode. The method was sensitive with a limit of quantification of 0.3 ng/mL and linear over the range of 0.3-30 ng/mL (=0.9998). Intra- and inter-day precision for analyte was <9.52% RSD with recoveries in the range 88.0-109.67% at three concentration levels. The validated method was successfully applied to quantitatively determine the compound OMBF in TCMIs and glucose injections. Our study indicates that this method is simple, sensitive, practicable and reliable, and could be applied for safety evaluation and quality control of TCMIs and glucose injections.