Detection and identification of intestinal pathogenic bacteria by hybridization to oligonucleotide microarrays

AIM: To detect the common intestinal pathogenic bacteria quickly and accurately.METHODS: A rapid (＜3 h) experimental procedure was set up based upon the gene chip technology. Target genes were amplified and hybridized by oligonucleotide microarrays.RESULTS: One hundred and seventy strains of bacteria in pure culture belonging to 11 genera were successfully discriminated under comparatively same conditions, and a series of specific hybridization maps corresponding to each kind of bacteria were obtained. When this method was applied to 26 divided cultures, 25 (96.2%) were identified.CONCLUSION: Salmonella sp., Escherichia coli, Shigella sp., Listeria monocytogenes, Vibrio parahaemolyticus,Staphylococcus aureus, Proteus sp., Bacillus cereus,Vibrio cholerae, Enterococcus faecalis, Yersinia enterocolitica, and Campylobacter jejuni can be detected and identified by our microarrays. The accuracy, range,and discrimination power of this assay can be continually improved by adding further oligonucleotides to the arrays without any significant increase of complexity or cost.

Metabolomic Study on Vitamins B_1, B_2, and PP Supplementation to Improve Serum Metabolic Profiles in Mice under Acute Hypoxia Based on ~1H NMR Analysis

Objective To explore metabolic changes after acute hypoxia and modulating effect of vitamins B1, B2, and PP supplementation in mice exposed to acute hypoxia. Methods Fifty male Kunming mice were randomly divided into 5 groups： normal, acute hypoxia, acute hypoxia with 2, 4 and 8 time- vitamins B1, B2, and PP supplementation . All mice were fed with corresponding diets for two weeks and then were exposed to a simulated altitude of 6 000 meters for 8 h, except for the normal group. Nuclear magnetic resonance analysis was used to identify the changes of serum metabolic profiles. Results There were significant changes in some serum metabolites under induced acute hypoxia, essentially relative increase in the concentrations of lactate, sugar and lipids and decrease in ethanol. The serum levels of choline, succinate, taurine, alanine, and glutamine also increased and phosphocholine decreased in the acute hypoxia group. After vitamins B1, B2, and PP supplementation, all these metabolic changes gradually recovered. Conclusion Significant changes in serum metabolic profile were observed by metabolomics in mice exposed to acute hypoxia, and vitamins B1, B2, and PP supplementation proved to be beneficial to improving some metabolic pathways. It is suggested that the dietary intakes of vitamins B1, B2, and PP should be increased under hypoxia condition.

Characterization of Hapten-Protein Conjugates for Immunoassay of Polycyclic Aromatic Hydrocarbons(PAHs)

Preparation and characterization of the hapten-protein conjugates are fundamental to developing environmental immunoassays. As a hapten, 1-pyrenebutyric acid（PBA） was conjugated to the carrier protein of bovine serum albumin（BSA） or ovalbumin（OVA） by active ester method. Infrared spectra（IR） showed that PBA-BSA and PBA-OVA conjugates were successfully prepared. The number of the haptens conjugated to the carrier protein was determined by ultraviolet spectra（UV） and matrix-assisted laser desorption ionization time-of-flight mass spectrometry（MALDI-TOF-MS）. The calculated average binding ratios of PBA/BSA and PBA/OVA were 18：1 and 10：1 by UV, and 31：1 and 22：1 by MALDI-TOF-MS, respectively. Although there was a discrepancy between the results determined by the two methods, both of them were useful for the characterization of the hapten-protein conjugates. The antibody was produced against the antigen of PBA-BSA, and the affinity was tested by the double agar diffusion method The conjugates and the antibody could be used for developing a sensitive and selective immunoassay of polycyclic aromatic hydrocarbons（PAHs）.

A New Hapten for Immunoassay of Aldicarb

A new hapten, aldicarb oxime succinic ester （AOSE）, was synthesized for immunoassay of aldicarb. It was conjugated to proteins by active ester method. Polyclonal antibody was raised against AOSE-BSA （bovine serum albumin） conjugate. Enzyme-linked immunosorbent assays （ELISAs） showed that this antiserum had high affinity to aldicarb and can be used for sensitive and selective immunoassay of aldicarb.

Transcriptomic Analysis of Aflatoxin B1-Regulated Genes in Rat Hepatic Epithelial Cells

Aflatoxins are the most popular hepatotoxicants. Chronic exposure to aflatoxins leads to a wide variety ofliver diseases, such as hepatocellular carcinoma. In this study, we analyzed the genome wide expression profiles ofaflatoxin B1-induced rat hepatic epithelial cells. The expression of 325, 184 and 199 special genes was altered whenexposed to 0.03, 0.1 and 0.2 μmol/L aflatoxin B1 respectively, and 239 genes were commonly expressed. After thefunctional analysis on these dose-special genes, we determined several key pathways related to hepatotoxicity, such asTGF-beta signaling pathway, tight junction, adherens junction, the regulation of actin cytoskeleton, ErbB signalingpathway, p53 signaling pathway, pathways in cancer and axon guidance. Common genes were mainly associated withfocal adhesion, ECM-receptor interaction, and cell adhesion molecules. Gene ontology annotations showed a goodconcordance with these pathways. The quantitative real-time polymerase chain reaction（PCR） analysis of selectedgenes showed similar patterns in microarrays. The toxicogenomic study provides a better understanding of molecularmechanisms of aflatoxins.

Study of Oligonucleotide Fixation on Bilayer Lipid Membranes by Patch-clamp Pipette Support

One kind of novel BLMs was fabricated by patch-clamp pipette technology characterized in considerably sensitive to changes of electrochemical parameters.Detectiye currents and voltage presented linear relationship when BLMs was formed and it could be confirmed by Gramicidin method.Ion current was increased by dihexyl (C_ (12)) modified ssDNA fixed on the BLMs and also indicated linear relationship to ssDNA's concentration due to the interaction of (C_ 12)-ssDNA and BLMs.Further more,the regression equations were different from BLMs fixed with ssDNA probe and a blank control BLM in the same experimental conditions.The ssDNA probe was successfully fixed on patch-clamp pipette supported-BLMs.Based on our studies,a biosensor with reactive element of patch-clamp pipette-supported BLMs has been established.

Photocatalytic properties of TiO_2 bonded active carbon composites prepared by SOL-GEL

Photocatalyst of TiO2 bonded active carbon （TiO2/AC）, was prepared via sol-gel method from a mixture of TiO2 sol with active carbon. Post heat treatment was performed at 250 ℃ for 2 h in air and then kept at 400 ℃ to 600 ℃ under a flow of nitrogen for 2 h. The TiO2/AC composites obtained were characterized by SEM, XRD, UV-vis and BET. The photocatalytic activities of the TiO2/AC composites were studied in comparison with TiO2, AC, P-25 and a mixture of TiO2 and AC, respectively. The Ramnant rate of Rhodamine B absorbed by the active carbon is found to be almost 70% and the remnant rates of the Rhodamine B decolorized by TiO2 and the mixture of TiO2 and the active carbon are 30% and 25%, respectively. However, nearly complete removal of Rhodamine B is observed for a TiO2/AC composite after 200 min under UV irradiation, which will take the P-25 commercial product 5 h. Therefore, the TiO2/AC composite is much more effective in decolorization of aqueous Rhodamine B. In addition, the composite can be easily separated from solutions.

A new anti-hypoxia functional agent ——Schizophyllum commune fermented broth and its biochemical mechanisms

In order to overcome hypoxia induced sickness,a stable source of anti-hypoxia functional agents, Schizophyllum commune fermented broth has been developed in this study. Animal experiments were conducted to examine its anti-hypoxia activities and possible mechanisms involved. The acute hypoxic experiment showed that Schizophyllum commune fermented broth could significantly prolong the survival time of mice. The underlying mechanisms were associated with improved energy metabolism based on a study carried out in rats exposed to a low pressure chamber simulating the low pressure environment of 8 000 m altitude. It was concluded that the Schizophyllum commune fermented broth was an effective anti-hypoxia functional agent and could be greatly bene- ficial to those living and working at high altitudes,such as people who reside in the reconstruction regions of Yushu.

Bacterobilia in pancreatic surgery-conclusions for perioperative antibiotic prophylaxis

BACKGROUND Jaundice or preoperative cholestasis(PC)are typical symptoms of pancreatic masses.Approximately 50%of patients undergo preoperative biliary drainage(PBD)placement.PBD is a common cause of bacterobilia(BB)and is a known surgical site infection risk factor.An adjustment of preoperative antibiotic prophylaxis(PAP)may be reasonable according to the profile of BB.For this,we examined the microbiological findings in routine series of patients.AIM To investigate the incidence and profile of biliary bacterial colonization in patients undergoing pancreatic head resections.METHODS In the period from January 2009 to December 2015,285 consecutive pancreatic head resections were performed.Indications for surgery were malignancy(71%),chronic pancreatitis(18%),and others(11%).A PBD was in 51%and PC was in 42%.The standard PAP was ampicillin/sulbactam.Intraoperatively,a smear was taken from the hepatic duct.An analysis of the isolated species and resistograms was performed.Patients were categorized according to the presence or absence of PC(PC+/PC-)and PBD(PBD+/PBD-)into four groups.Antibiotic efficiency was analyzed for standard PAP and possible alternatives.RESULTS BB was present in 150 patients(53%).BB was significantly more frequent in PBD+(n=120)than in PBD-(n=30),P<0.01.BB was present both in patients with PC and without PC:(PBD-/PC-:18%,PBD-/PC+:30%,PBD+/PC-:88%,PBD+/PC+:80%).BB was more frequent in malignancy(56%)than in chronic pancreatitis(45%).PBD,however,was the only independent risk factor in multivariate analysis.In total,357 pathogens(342 bacteria and 15 fungi)were detected.The five most common groups(n=256,74.8%)were Enterococcus spp.(28.4%),Streptococcus spp.(16.9%),Klebsiella spp.(12.6%),Escherichia coli(10.5%),and Enterobacter spp.(6.4%).A polymicrobial BB(PBD+:77% vs PBD-:40%,P<0.01)and a more frequent detection of Enterococcus(P<0.05)was significantly associated with PBD+.In PBD+,the efficiency of imipenem and piperacillin/tazobactam was significantly higher than that of the standard PAP(P<0.01).CONCLUSION PBD-/PC-and PBD-/PC+were associated with a low rate of BB,while PBD+was always associated with a high rate of BB.In PBD+patients,BB was polymicrobial and more often associated with Enterococcus.In PBD+,the spectrum of potential bacteria may not be covered by standard PAP.A more potent alternative for prophylactic application,however,was not found.

Monocrotophos Molecularly Imprinted Microspheres Prepared by Precipitation Polymerization in Acetonitrile

Molecularly imprinted microspheres (MIP) for monocrotophos have been prepared by precipitation polymerization in acetonitrile (ACN) 60℃,24 h,using methacrylic acid (MAA),ethylene glycol dimethacrylate (EGDMA) and 2, 2-azobisiobutyronitrile (AIBN) as functional monomer,cross-linker and initiator,respectively.The recognition mechanism was elucidated by UV-vis spectra and computer modeling.Equilibrium binding experiment was employed to investigate the rebinding properties,Scatchard analysis showed that specific binding sites formed in the imprinted microspheres,and there were two kinds of binding sites,one was high binding sites,the other was low binding sites.This microspheres can be useful affinity absorbent used for organophosphorus pesticides separation and purification in food and environmental analysis.

The Method of Fast on-site Detection and Real-time Release of Ammonia Nitrogen in Water

Objective:This paper aims to establish a simple and practical method for the rapid detection of ammonia nitrogen in water on the spot,and to transmit the detection results to the Internet via GSM network,and to publish and update them in real time.Methods:Phenol salt colorimetry was used to measure the absorbance value of indigo phenol blue,the product of the reaction between ammonia nitrogen and phenol salt in water samples,using sodium nitrosoferricyanide sodium hydroxide as catalyst and a microphotoelectric colorimetric instrument developed by ourselves,or a simple visual colorimetric semi-quantitative method was used to measure the ammonia nitrogen content in water samples.Then,the general GSM wireless communication module built in the microphotoelectric colorimeter was used to realize the remote transmission of the test result data and the real-time update and release on the Internet.Results:The results of this method showed that the correlation of the method was significant,and the precision and accuracy were similar to the national standard Nessler's reagent spectrophotometry.The relative standard deviation is 4.4%,and the relative error is 2.7%.In 5-10 min,the detection of ammonia and nitrogen in single water sample can be completed on site,and the results can be released.For quantitative and semi-quantitative detection,the lowest detection concentrations are 0.05 mg/L and 0.2 mg/L,respectively,which are basically free from the interference of pH and common ions.In the coverage area of GSM network,the wireless transmission of data results was unobstructed and delayed,and the effect was satisfactory.Conclusion:The method is simple,rapid,practical and reliable,which is suitable for the field rapid determination of ammonia nitrogen in water,and the real-time remote transmission of the detection results.It provides a high-efficiency,low-cost and simple technical means for the field water quality monitoring and the rapid acquisition of water quality data.

A Rapid Processing Technology of Water Quality Microfluidic Chip

In this study,a unique rapid processing technology for microfluidic chips made of polymethylmethacrylate(PMMA)was realized.The common laser engraving machine is used to etch the chip reaction unit and microchannel,and the printing chip is what you see is what you get;the pressurized heat sealing technology is used to quickly complete the chip sealing and packaging;the metal electrodes and lines that need to be laid are embedded into the chip by hot melting;the contact points on the fixed base of the contact chip card are used to connect with the external equipment,so as to make the bearing sample react,detect and complex lines and chips.It is self-contained and isolated from the external equipment circuit.The chip becomes disposable and can be replaced quickly and conveniently.The chip processed by this technology has rapid,cheap and convenient improvement and innovation,which makes the production of microfluidic chip easier and more practical,and even makes the chip a disposable consumable with general interface,which will greatly promote the industrialization of microfluidic chip,and has market-oriented promotion value in the field of water quality and food detection.