Study on the transfer mechanism and destructive law of the bacterial antibiotic resistance genes disinfected by chlorination / 中华预防医学杂志

Objective@#To study the response of Escherichia coli (E. coli) HB101 (plasmid pUC19) and its carried antibiotic resistance genes to the process of cholorination under different environmental conditions.@*Methods@#The E. coli strain was reacted with sodium hypochlorite at the concentration of 0.5, 0.75, 1.00, and 0.55 mg/L, then the residual chlorine and the colonies were detected at the 0.25, 1, 2, 5, 10, 20, and 30 min of the reaction, respectively. The first order disinfection kinetic model and EFH model were used to evaluate the inactivation effect of E. coli (plasmid pUC19) treated by sodium hypochlorite, while the plasmid pUC19 and antibiotic resistance gene ampr were detected by PCR method. Besides, the logarithm of Ct (residual chlorine in t) under different concentration were calculated.@*Results@#The temperature and pH value played important roles on the inactivation of E. coli and elimination of plasmid pUC19 and ampr under the function of sodium hypochlorite. The Ct value needed for 5-log of E.coli HB101(pUC19) inactivation at 4, 20, 36 ℃ was 11.92, 10.28, 7.67, respectively, and when the pH was in 6.0, 7.0, 8.0, with chloride concentration were 0.75, 0.70, 0.55 mg/L, the Ct value needed for reached to 6.68, 10.28, 15.73 min·mg/L. At pH 7.2 condition, when the temperature was 4, 20, 36 ℃, and chloride concentration were 9, 5, 3 mg/L.The required Ct values to completely destroy the transformation function of free antibiotic resistant plasmids were 36.11, 34.17,16.09 min·mg/L. Sodium hypochlorite disinfection can release free ampr gene and even the transformed plasmid pUC19, and pollute the water body. Only when the Ct value reached 903.03 min·mg/L, the complete ampr gene can be destroyed which was far more exceed the bacterial lethal Ct value.@*Conclusion@#Even if all the antibiotic resistant bacteria were inactivated, the antibiotic resistant plasmids or genes might still maintain complete with the transformable function, which may result in new potential risks of waterborne diseases.

The impact of temperatures on the results tested with different blood glucose testing methods for critical patients in ICU / 中国实用护理杂志

Objective To compare the impact on the results tested with arterial blood gas analysis and peripheral blood with glucose meter for critical patients in ICU in different temperature states. Methods The samples of venous biochemical test, blood arterial blood gas analysis and peripheral blood of 196 cases of critical patients in ICU were collected synchronously, and measure the D-value, correlation and bias adjustment factor of glucose blood tested with a synchronous fasting blood glucose test and venous/biochemical analyzer in different temperature states and different blood glucose groups, and the results of blood glucose test were analyzed. Results In normal temperature state, hypoglycemia simultaneous rapid intravenous glucose monitoring blood glucose level results compared with the lowest positive rate 3.31%(5/151), while the pairwise comparison showed there was both statistical signifcance between hypoglycemia group and target group (χ2=38.469), hyperglycemia group and target group (χ2=15.504) when choosing a synchronous fasting blood glucose test and intravenous blood glucose test (P<0.01). In high temperatures state, hypoglycemia simultaneous rapid intravenous glucose monitoring blood glucose level results compared with the lowest positive rate 0. There was both statistical significance between hypoglycemia group and target group (χ2=18.187), hypoglycemia group and hyperglycemia group (χ2=12.857) when choose a synchronous fasting blood glucose test and intravenous blood glucose test (P<0.01). Conclusions In high temperatures state, a synchronous fasting blood glucose test can not reflect the true value of blood glucose for critical patients.

Mechanism of Escherichia coli injury under UV disinfection / 军事医学

Objective To study the inactivation kinetics and injury mechanism of Escherichia coli under UV disinfection in drinking water.Methods The inactivation kinetics of E.coli ATCC 25922 was determined by plate count methods in the UV disinfection experiment.The morphology,cell membrane permeabilization and injury of biological macromolecules were observed under a transmission electron microscope (TEM).The rate of ONPG hydrolysis and changes in activities of antioxidant enzymes were observed Raman spectroscopy.Results the changes of damaged cells involved morphological damage such as loss of the structural integrity of the wall and membrane,condensation of cellular material and leakage of significant amounts of cytoplasmic material,a more than four-fold increase of cell membrane permeabilization and damage to the structure of protein,nucleic acids and phospholipid.Conclusion UV disinfection can lead to a multi-target damage.

Characteristics of astrovirus infection and typing characteristics analysis among children hospitalized with diarrhea in Tianjin / 中华检验医学杂志

Objective To study the pathogenic prevalence and genotypes of astrovirus among children under 5 years old hospitalized with diarrhea in Tianjin. Methods A total 837 stool specimens were collected from children with diarrhea hospitalized in Tianjin children's hospital from May 2008 to April 2009. Astrovirus antigens were detected using ELISA and the postive specimens were inoculated in CaCo-2cells. After the CPE caused by virus were observed, the total RNA of virus was extracted, then the genomc fragments of the strains were amplified by using RT-PCR and confirmed by sequencing of the RT-PCR products. Detection of rotavirus was employed by Colloidal Gold Device. Results Astrovirus antigen was found positive in 3.0% of the patients. The coinfection rate of astrovirus and rotavirus was 0. 7% (6/837).Ninety-six persent of children with astrovirus diarrhea were younger than 2 years of age, Forty-eight persent of children with astrovirus diarrhea were younger than 6 months. The astrovirus infections occurred mainly between August 2008 and April 2009. Of the 21 astrovirus positive specimens, 11 cases were successfully identified by RT-PCR and they were all serotype 1. Conclusion Astrovirus is a major cause of nonbacterical diarrhea between 2008 and 2009 in Tianjin, and the predominant serotype is type 1.

Detection and genotyping of rotavirus among children under 5 years old hospitalized with diarrhea in Tianjin / 中华检验医学杂志

Objective To study the prevalence and genotypes of rotavirus (RV) among children,< 5 years old hospitalized with viral diarrhea in Tianjin. Methods Stool specimens were collected from hospitalized diarrhea children in Tianjin children's hospital between May 2008 and April 2009. Detection of rotavirus was employed by Colloidal Gold Device. The detected positives were inoculated to MA-104 cells. The total RNA of virus was extracted after CPE which was caused by rotavirus were observed, The VP7 serotypes were determined by using RT-PCR to amplify the VP7 gene and sequencing the RT-PCR products.The clinical data for each patient were also collected. Results Among 837 specimens, the RV antigen positive rate was 26. 3% (220/837). Among all the children with rotavirus diarrhea, 90. 5% (199/220)were < 2 years old. The prevalence of rotavirus diarrhea in children peaked during Oct. 2008 through Apr.2009. Of the 208 rotavirus positive specimens, 95 were successfully identified by RT-PCR Thirty-five positive strains of RV were sequenced, and the sequencing results showed that 32 positive strains were belonged to rotavirus G1 type, 2 positive strains were belonged to rotavirus G3 type and 1 positive strain were belonged to rotavirus C9 type. Conclusion RV was the dominant etiological agent for infantile diarrhea infection in Tianjin, and the predominant serotype was G1.

Construction and evaluation of reference standards for detection and quantification of Klebsiella pneumoniae using real-time PCR / 药物分析学报

Objective To construct reference standards for detection and quantification of Klebsiella pneumoniae (K.pneumoniae) with SYBR Green I-based real-time PCR assay. Methods Primers were designed based on the published sequence of the phoE gene of K.pneumoniae. The standard was prepared by cell culture, PCR and T-A clone methods, and was identified by colony PCR and DNA sequencing. Results The standard curve showed a very good linear negative regression between threshold cycle (Ct) and Log starting quantity of copy number. The detection range was from 5.2 to 5.2×106 copies per reaction, and the detection limit was 6 copies per reaction. The coefficients of variance (CVs) of three parallel experiments were in the range of 0.05%-0.91%. Conclusion The reference standards have high stability and reproducibility. They can be used in the quantitative detection of K.pneumoniae.

Detection and identification of intestinal pathogenic bacteria by oligonucleotide array / 中华传染病杂志

Objective To detect the intestinal pathogenic bacteria quickly and accurately from water. Methods An experimental procedure is set up using the gene chip technology to detect and identify common intestinal pathogenic bacteria from water. Target gene was amplified and hybridized with prepared gene chip.Results 143 strains of bacteria in pure culture belong to 9 genera are successfully discriminated under comparatively same condition and a series of specific hybridization maps corresponding to each kinds of bacteria are obtained.Conclusions Salmonella spp., Shigella spp., Staphylococcus spp., Proteus spp., Escherichia coli, Yersinia enterocolitica, Listeria monocytogenes and Vibrio parahaemolyticus are detected and identified by the technology of gene chip. The accuracy, range, and discriminatory power of the assay can be continually improved by adding further oligonueleotides to the arrays without significantly increasing complexity or cost.

Preliminary Screen and Identification of One Nitrobacteria / 环境与健康杂志

Objective To screen and seperate nitrobacteria that could be used to treat nitrogenous compound pollution.Methods Autotrophic nitrite-oxidizing microorganisms were screened by enrichment culture from soil.After morphological and biological detection,primers were designed to detect the distinctive gene norB of nitrobacteria.The PCR production was se-quenced,and the homology was identified according to the sequence in Genbank.Results One strain of bacterium was screened that could oxidize nitrite.This bacterium was small,light-yellow bacilli.The expected-size DNA fragments could be amplicated by PCR.The sequence of a PCR production was blasted in Genbank and showed99%consistent with norB gene of N hamburgensis.Conclusion It was preliminarily confirmed that the microorganism screened in this study might be nitrobac-terium.

Cloning and Sequencing of NorB Gene of Nitrobacterium / 环境与健康杂志

Objective To amplify and sequence the distinctive norB gene of Nitrobacterium. Methods The norB gene was amplified by PCR and was cloned into T-vector and then transformed into E.coli JM109. After white-and-blue selection, positive colonies were sequenced with T7 sequencing primers by Takara Company. Spliced with Vector NTI Suite software, the homologous analysis of sequences were conducted in Genbank through Internet. Results The results showed that all of norB genes obtained from the nitrite-oxidizing bacteria were homologous with the norB gene of Nitrobacterium hamburgensis in Genbank. The homology ranged from 96% to 98%, and there were no frameshift mutations, which guaranteed the correct ORF. Conclusion The obtained genes are norB genes indeed.

Review of Research in Aerobic Denitrification by Microorganisms / 环境与健康杂志

Nitrogen pollution in water body can not only cause eutrophication but also has direct hazardous effects on animals and human beings. The removal of ammonium is an important process in modern wastewater treatment systems. It is generally achieved by a traditional treatment system of combination of two processes,aerobic nitrification and anoxic denitrification,but these processes are very complex and the cost is higher. In recent years,some new principles have been proposed,such as aerobic denitrification,anaerobic ammonium oxidation,heterotrophic nitrification,which make simultaneous nitrification-denitrification possible. The domestic and foreign study progress in aerobic denitrification was reviewed in this paper.

Pollution of Bisphenol-A and Advancement of Degradating and Removing / 环境与健康杂志

With the development of science and society, increasing attention has been paid to the pollution of environmental estrogens. As one of environmental estrogens, bisphenol-A has been used in many fields, but it has many aspects of toxicity. The studies on the toxicity, environmental pollution, degradation and removal of bisphenol-A have become the research emphasis in recent years. The advances in the studies of these aspects were reviewed in this article briefly.

Conditions for Pseudomonas sp.W2 Culture and Bisphenol A Degradation / 环境与健康杂志

Objective To study the condition for Pseudomonas sp. W2 culture and degradation of bisphenol A(BPA). Methods The growth curve of Pseudomonas sp. W2 and BPA degradation curve were made concerned pH, temperature, aeration, carbon sources and nitrogen sources affecting Pseudomonas sp. W2 culture and BPA degradation. Results Under the conditions of pH=7, 25-35 ℃, certain carbon sources and nitrogen sources, Pseudomonas sp. W2 grew well and showed a good efficiency of BPA degradation. Conclusion Some wide conditions can meet the requirement of Pseudomonas sp. W2 growth and BPA degradation.

Study on the Inactivation Mechanisms of HAV by Chlorine / 环境与健康杂志

Objective To investigate the feasibility of reverse transcription_polymerase chain reaction (RT_PCR) to evaluate the inactivation efficacy of viruses in water, and to discuss the mechanisms of HAV inactivation by chlorine. Methods Cell cultrue, ELISA method and long_overlapping RT_PCR were developed to detect the infectivity, antigenicity and entire genome of HAV inactivated by chlorine. Results The cell culture results revealed that the infectivity was completely inactivated after exposure to 10 mg/L or 20 mg/L of cholrine for more than 30 minutes, the antigenicity was completely inactivated after exposure to 10 mg/L of chlorine for 60 minutes. The 5' nontranslated region (5'NTR) of neculear acids of HAV was the most sensitive to chlorine, which was confirmed with the inactivation of infectivity of HAV. Conclusions The results implied that the inactivation of HAV by chlorine was due to the loss the 5' NTR. It was believed that PCR could be used to assess the efficacy of disinfection of HAV by chlorine and also could be applied to research the inactivation mechanisms of viruses by disinfectants.

INFLUENCE OF PASSIVE SMOKING ON LEARNING AND MEMORY ABILITY OF MOUSE OFFSPRING AND INTERVENTION BY ANTIOXIDANTS / 营养学报

Objective : To study the protective effects of two antioxidants on the influence of passive smoking on learning and memory ability of mouse offspring. Method: Passive smoking model of pregnant mice was established. Learning and memory ability was evaluated by water maze and long term potentiation (LTP). Nitric oxide (NO) content and nitric oxide synthase (NOS) activity of brain, vitamin E(VE) concentration and reactive oxygen species (ROS) of serum were determined. Results: Latency (the swimming time from beginning to endpoint) and errors (the number of entering blind end) in control and two antioxidant groups were shorter as compared with tobacco smoking (TS) group after 6 d in water maze test, and still shorter after 10 d in control and TS+VE groups. LTP was inhibited in TS group but increased significantly in two antioxidant groups. NOS activitiy was significantly higher in TS group in comparisonwith the control. NO content of TS+VE group was significantly lower than TS and TS+Q groups. Serum VE concentration and ROS level were correlated with the results of latency in water maze and LTP. Conclusion: Passive smoking of the pregnant mice may restrain LTP formation through disturbance of hippocampus function, and reduce the learning and memory ability of the offspring and VE may protect such effects.