[Virulence genes and antimicrobial resistance of Bacillus cereus in prepackaged pastries sold in Taizhou from 2020 to 2022].

OBJECTIVE: To investigate the virulence genes and antimicrobial resistance of Bacillus cereus from the pre-packaged pastries in Taizhou city. METHODS: 500 pre-packaged patries were collected in taizhou city market. 97 Bacillus cereus strains were detected from them by GB 4789.14-2014 method and identified with 4 houseking genes, then 13 virulence genes were detected by polymerase chain reaction(PCR)method and the antimicrobial resistance of Bacillus cereus to 19 antibiotics was detected by paper diffusion method. RESULTS: The result showed that the contamination rate of Bacillus cereus was 19.4% in 500 pre-packaged pastries. The detection rate of four housekeeping genes groEL, gyr B, rpoB and Vrr were 100%, 94.8%, 97.9% and 96.9%, respectively, and 89.7% at the same time. The virulence gene test result showed that the detection rate of nheABC, entFM, bceT, cytK and hblABCD were 91.8%, 88.7%, 61.9%, 51.6% and 25.8%, emetic virulence genes had the lowest detection rate, ces and EMl were 4.1%, cer was 5.2%. 97 Bacillus cereus strains show different degrees of drug resistance to 14 antimicrobials, the resistance rates to penicillin, ampicillin, cefotaxime and cotrimoxazole were higher than 95%, but they were completely sensitive to streptomycin, vancomycin and chloramphenicol. CONCLUSION: There is a risk of contamination by diarrhea-type Bacillus cereus and vomiting-type Bacillus cereus in prepackaged pastries in Taizhou. The isolated and identified Bacillus cereus has multiple-drug resistance.

[Variation characteristics of plant electrical signal and their relationship with negative air ion under different light intensities.] / ä¸åŒå ‰ç §å¼ºåº¦ä¸‹æ¤ç‰©ç”µä¿¡å·å˜åŒ–ç‰¹å¾åŠå ¶ä¸Žç©ºæ°”è´Ÿç¦»å­çš„å ³ç³».

Negative air ion (NAI) is an essential indicator for measuring air cleanliness of a given area, with vital role in regulating psychological and physiological functions of human body. The photoelectric effect is an important source and influencing factor for the generation of NAI during photosynthesis, but the photoelectric effect is extremely weak and difficult to monitor. Plant electrical signal is an important indicator that indirectly reflects photoelectric effect. Previous studies mostly focused on the spatiotemporal variation of NAI in different forest communities and its relationship with meteorological factors. At present, there is little research on NAI and plant electrical signal. In this study, we explored the effect of different light intensities (0, 150, 300, 500, 700, 800, 1000 and 1200 µmol·m-2·s-1) on characteristics of the plant electrical signal and its relationship with negative air ion, with Pinus bungeana as the research object. The results showed that the intensity of plant electrical signal increased significantly with the increases of light intensity in the illumination range of 0-700 µmol·m-2·s-1. When light intensity reached 700 µmol·m-2·s-1, plant electrical signal activity reached the highest level, and plant was inhibited by light when light intensity increased further, with plant electrical signal activity decreased. The frequency-domain parameters (edge frequency, gravity frequency, power spectrum entropy and power spectrum peak) of plant electrical signals were significantly correlated with NAI. The correlation coefficient between edge frequency (E) and NAI was the highest, the relationship between them was NAI=30.981E+168.814 (R2=0.54), and the mean square error was 52.203. There was a significant correlation between plant electrical signals and NAI, which could characterize the change rule of NAI, and provide scientific evidence for further understanding the contribution potential and production mechanism of forest to NAI.

Qualitative and quantitative adsorption mechanisms of zinc ions from aqueous solutions onto dead carp derived biochar.

The objective of this study is to investigate the qualitative mechanisms of Zn2+ adsorption on carp biochars (CMBx) produced from dead carp at different temperatures (450-650 °C) and their quantitative contribution. The pseudo second order kinetic model and the Langmuir model could fit the kinetic and isothermal adsorption data well, respectively. The intra-particle diffusion was the main rate-limiting step but not the only rate-limiting step. The maximum adsorption capacity obtained from the Langmuir model for CMB650 was 87.7 mg g-1 which was greater than those of other biochars. Precipitation with minerals, ion exchange, and complexation with functional groups (OFGs) were the main adsorption mechanisms. Quantum chemistry calculations confirmed that the functional groups (e.g., hydroxyl, carboxyl and C[double bond, length as m-dash]C) tended to bind with Zn2+ more strongly than with Ca2+ and Mg2+, because the structure of the complex formed by the former was more stable. The contribution of different adsorption mechanisms varied with the pyrolysis temperature to prepare biochar. With increasing pyrolysis temperature, the contribution of the interaction between Zn2+ and the minerals increased from 46.4% to 84.7%, while that of complexation with OFGs decreased from 41.7% to 4.7%. Overall, the mechanism of Zn2+ adsorption on CMB450 was dominated by complexation with OFGs and exchange with cations (accounting for 73.2%), while the mechanisms on CMB650 were dominated by the interaction with minerals. In view of the total adsorption capacity, 650 °C was the optimized pyrolysis temperature for CMBx preparation and adsorption treatment of Zn-contaminated water. These results are useful for screening effective biochars as engineered sorbents to treat Zn-containing wastewater.

microRNA-665 is down-regulated in gastric cancer and inhibits proliferation, invasion, and EMT by targeting PPP2R2A.

Recently, microRNA-665 (miR-665) has been reported to function as both tumour suppressor and oncogene in several cancer types, including gastric cancer, hepatocellular cancer, and lung cancer. However, the biological function of miR-665 and its precise mechanisms in gastric cancer (GC) have not been well clarified. The aim of this study was to study the roles of miR-665/PPP2R2A axis in GC. The levels of PPP2R2A and miR-665 were detected by quantitative PCR assay in GC tissues and cell lines. Moreover, the biological roles of miR-665 and PPP2R2A in GC cells were assessed by cell proliferation, invasion, and epithelial-mesenchymal transition (EMT). The mRNA and protein levels of PPP2R2A were determined by using quantitative PCR and Western blotting assays. Luciferase assays were used to confirm that PPP2R2A was one target of miR-665. In this study, the miR-665 level was dramatically reduced in GC tissues and cell lines, and the PPP2R2A expression was significantly enhanced. What is more, the PPP2R2A expression was negatively related to the miR-665 level in GC tissues. Furthermore, up-regulation of miR-665 obviously restrained GC cells proliferation, invasion, and EMT. We confirmed that miR-665 could directly target PPP2R2A by luciferase reporter assay. Besides, knockdown of PPP2R2A also could markedly inhibit the proliferation, invasion and EMT of GC cells. Finally, overexpression of miR-665 in GC cells partially reversed the promoted effects of PPP2R2A up-regulation. Overexpression of miR-665 restrained GC cells proliferation, invasion and EMT via regulation of PPP2R2A. SIGNIFICANCE OF THE STUDY: miR-665 has been reported to function as oncogene or tumour suppressor in different cancers. However, the precise roles of miR-665 in GC have not been elucidated. Our study for the first time demonstrated that miR-665 level was significantly down-regulated in GC. Additionally, miR-665 overexpression inhibited cell growth, invasion, and EMT of GC. Moreover, our data suggested a significant negative correlation between miR-665 and PPP2R2A expression in GC. MiR-665 suppressed GC cell proliferation, invasion, and EMT by directly targeting PPP2R2A, which suggested important roles for miR-665/PPP2R2A axis in the GC pathogenesis and its potential application in cancer therapy.

[Establishment of screening and confirmation method for the analysis of pesticide residues in tea by ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry].

Based on ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-QTOF-MS), UNIFI 1.7.0 software was used to establish a screening and confirmation method for the analysis of 91 pesticide residues, which was qualitatively validated and applied to tea screening in the circulation market. By analyzing the collected pesticide certified reference materials (CRM), a mass spectral database of 91 pesticides was constructed. The database contains multiple types of information, including formulas, theoretical exact masses, retention times, characteristic fragment ions, and adduct types. The samples were extracted with acetonitrile, purified on a solid-phase extraction column, and separated on an Acquity BEH C18 column. All the data (ESI+) were acquired in MSE mode and analyzed using the UNIFI information system. Analyte detection was based on the retention time deviation ±0.1 min, accurate mass deviation ±5×10-6, and major adduct forms including[M+H]+,[M+Na]+,[M+K]+, and[M+NH4]+. Screening was performed by the software in an automated fashion. Compound identification was accomplished with retention time matching and accurate mass measurements of the primary diagnostic ions for each analyte. To ensure accuracy of the identification results, information from the MS/MS profiles must be compared with online mass spectral libraries such as PubChem and MassBank. The SANTE/11813/2017 protocol for the validation of the screening method was followed. A mixed standard solution was spiked to 21 tea samples at four levels (0.01 mg/kg, 0.05 mg/kg, 0.10 mg/kg, and 0.20 mg/kg) to determine the screening detection limit (SDL) of each pesticide, and a total of 1911 pesticide/sample combinations were evaluated. The results revealed 66 pesticides with an SDL of 0.01 mg/kg, eight pesticides with an SDL of 0.05 mg/kg, one pesticide with an SDL of 0.10 mg/kg, three pesticides with an SDL of 0.20 mg/kg, and 13 pesticides with an SDL greater than 0.20 mg/kg. One pesticide showed matrix-inhibitory effects in the screening tests. Finally, the established method was used to analyze the pesticide residues in 22 tea samples available on the market. Six pesticide compounds were found in the tea samples, all of which were confirmed to be positive after artificial identification. This method provides a reference for the high-throughput screening and detection of pesticide residues in tea as well as a research approach for the analysis of various chemical contaminants in other matrices.

[Rapid determination of bongkrekic acid in Liushenqu by ultra performance liquid chromatography-tandem mass spectrometry].

A method for the rapid determination of biotoxin (bongkrekic acid) in the Liushenqu was established using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with methanol by ultrasonication, then the pH was adjusted to 8 using ammonia. After filtration, the extract was purified using an Oasis Max strong anion exchange resin column. The Waters HSS T3 column (100 mm×2.1 mm, 1.8 µm) was used for the UPLC-MS/MS analysis. The mobile phase was acetonitrile-10 mmol/L ammonium formate solution (containing 0.1% (v/v) formic acid). MS analysis was performed using an electrospray ionization (ESI) source in the negative and multiple reaction monitoring (MRM) modes. Under the optimum conditions, the linear range of bongkrekic acid was 0.5-100 µg/L (correlations coefficient (R2)>0.99). The recoveries of the bongkrekic acid were 80.6%-85.3%. The intra-day and inter-day relative standard deviations (RSDs) were in the range of 4.2%-6.8% and 8.2%-13.2%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were 0.4 µg/kg and 1.2 µg/kg, respectively. The results showed that bongkrekic acid residues were detected in Liushenqu, thereby confirming the supporting role of our method for the risk monitoring of biotoxins in health foods and Chinese herbal medicines. This method is simple, easy, sensitive, and suitable for the determination of the bongkrekic acid residues in Liushenqu.

Monodisperse Fe3O4/SiO2 and Fe3O4/SiO2/PPy Core-Shell Composite Nanospheres for IBU Loading and Release.

The magnetic targeting drug delivery system is an effective way of targeting therapy. In this study, the monodisperse Fe3O4 nanoparticles with a particles size of about 180 nm were first prepared via a solvothermal method. Subsequently, the core-shell structure Fe3O4/SiO2 and Fe3O4/SiO2/polypyrrole (PPy) composite nanospheres were successfully synthesized by coating Fe3O4 nanoparticles with SiO2 shell layer using the Stöber method and PPy shell by solvothermal method in turn. The as-prepared nanoparticles were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), and Ultraviolet-Visible spectrophotometer (UV-Vis). The results indicated that the as-prepared composite nanospheres displayed a well-defined core-shell structure and monodispersity. The thicknesses of SiO2 shell and PPy shell were ~6 nm and ~19 nm, respectively. Additionally, the as-prepared nanoparticles exhibited high saturation magnetization of 104 emu/g, 77 emu/g, and 24 emu/g, and have great potential applications in drug delivery. The drug loading and drug release of the Fe3O4/SiO2 and Fe3O4/SiO2/PPy composite nanospheres to ibuprofen (IBU) under stirring and ultrasonication were investigated. Their drug loading efficiency and drug release efficiency under ultrasonication were all higher than 33% and 90%, respectively. The drug release analyses showed sustained release of IBU from nanospheres and followed the Korsmeyer-Peppas model.

Fe3O4 Nanoparticles in Targeted Drug/Gene Delivery Systems.

Fe3O4 nanoparticles (NPs), the most traditional magnetic nanoparticles, have received a great deal of attention in the biomedical field, especially for targeted drug/gene delivery systems, due to their outstanding magnetism, biocompatibility, lower toxicity, biodegradability, and other features. Naked Fe3O4 NPs are easy to aggregate and oxidize, and thus are often made with various coatings to realize superior properties for targeted drug/gene delivery. In this review, we first list the three commonly utilized synthesis methods of Fe3O4 NPs, and their advantages and disadvantages. In the second part, we describe coating materials that exhibit noticeable features that allow functionalization of Fe3O4 NPs and summarize their methods of drug targeting/gene delivery. Then our efforts will be devoted to the research status and progress of several different functionalized Fe3O4 NP delivery systems loaded with chemotherapeutic agents, and we present targeted gene transitive carriers in detail. In the following section, we illuminate the most effective treatment systems of the combined drug and gene therapy. Finally, we propose opportunities and challenges of the clinical transformation of Fe3O4 NPs targeting drug/gene delivery systems.

DABCO-catalyzed Knoevenagel condensation of aldehydes with ethyl cyanoacetate using hydroxy ionic liquid as a promoter.

N-(2-Hydroxy-ethyl)-pyridinium chloride ([HyEtPy]Cl) was synthesized and explored as a novel promoter for 1,4-diazabicyclo [2.2.2] octane (DABCO)-catalyzed Knoevenagel condensation reactions, which showed better catalytic activity compared to other ionic liquid (IL) that had no hydroxyl group attached to the IL scaffold. The effect of hydrogen bond formation between the hydroxyl group of [HyEtPy]Cl and the carbonyl group of aldehyde played an important role in the Knoevenagel condensation reaction. In the [HyEtPy]Cl-H2O-DABCO composite system, Knoevenagel condensation reactions proceeded smoothly and cleanly, and the corresponding Knoevenagel condensation products were obtained in good to excellent yields in all cases examined. This protocol provides a versatile solvent-catalyst system, which has notable advantages such as being eco-friendly, ease of work-up and convenient reuse of the ionic liquid.

Preparation of nanometer-sized black iron oxide pigment by recycling of blast furnace flue dust.

Blast furnace (BF) flue dust is one of pollutants emitted by iron and steel plants. The recycling of BF flue dust can not only reduce pollution but also bring social and environmental benefits. In this study, leaching technique was employed to the treatment of BF flue dust at first. A mixed solution of ferrous and ferric sulfate was obtained and used as raw material to prepare nanometer-sized black iron oxide pigment (Fe(3)O(4), magnetite) with NaOH as precipitant. The optimal technological conditions including total iron ion concentration, Fe(3+)/Fe(2+) mole ratio, precipitant concentration and reaction temperature were studied and discussed carefully. The spectral reflectance and oil absorption were used as major parameters to evaluate performance of pigment. Furthermore, Fe(3)O(4) particles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Under optimized conditions obtained pigment has low average spectral reflectance (<4%), good oil absorption ( approximately 23%), high black intensity, and narrow size distribution 60-70 nm.

Isolation and characterization of endophytic Bacillus subtilis Jaas ed1 antagonist of eggplant Verticillium wilt.

An endophytic bacterial strain, Jaas ed1, was isolated from the interior of eggplant (Solanum melongena L.) stems in Jiangsu Province, China. According to the morphological and physiological characteristics and phylogenetic analysis of the 16s rDNA sequence, it was identified as Bacillius subtilis. Strain Jaas ed1 and its cell-free filtrate had strong antifungal activity against Verticillium dahliae. The strain was an internal colonizer within the eggplant without any harmful side effects to the plant. In greenhouse experiments, the strain cell suspension effectively controlled Verticillium wilt of eggplant, and its control efficiency was far more significant than that of the cell-free filtrate after inoculation of V. dahliae.