ToxR represses the synthesis of c-di-GMP in Vibrio parahaemolyticus / 生物工程学报

Vibrio parahaemolyticus, the main pathogen causing seafood related food poisoning worldwide, has strong biofilm formation ability. ToxR is a membrane binding regulatory protein, which has regulatory effect on biofilm formation of V. parahaemolyticus, but the specific mechanism has not been reported. c-di-GMP is an important second messenger in bacteria and is involved in regulating a variety of bacterial behaviors including biofilm formation. In this study, we investigated the regulation of ToxR on c-di-GMP metabolism in V. parahaemolyticus. Intracellular c-di-GMP in the wild type (WT) and toxR mutant (ΔtoxR) strains were extracted by ultrasonication, and the concentrations of c-di-GMP were then determined by enzyme linked immunosorbent assay (ELISA). Three c-di-GMP metabolism-related genes scrA, scrG and vpa0198 were selected as the target genes. Quantitative real-time PCR (q-PCR) was employed to calculate the transcriptional variation of each target gene between WT and ΔtoxR strains. The regulatory DNA region of each target gene was cloned into the pHR309 plasmid harboring a promoterless lacZ gene. The recombinant plasmid was subsequently transferred into WT and ΔtoxR strains to detect the β-galactosidase activity in the cellular extracts. The recombinant lacZ plasmid containing each of the target gene was also transferred into E. coli 100λpir strain harboring the pBAD33 plasmid or the recombinant pBAD33-toxR to test whether ToxR could regulate the expression of the target gene in a heterologous host. The regulatory DNA region of each target gene was amplified by PCR, and the over-expressed His-ToxR was purified. The electrophoretic mobility shift assay (EMSA) was applied to verify whether His-ToxR directly bound to the target promoter region. ELISA results showed that the intracellular c-di-GMP level significantly enhanced in ΔtoxR strain relative to that in WT strain, suggesting that ToxR inhibited the production of c-di-GMP in V. parahaemolyticus. qPCR results showed that the mRNA levels of scrA, scrG and vpa0198 significantly increased in ΔtoxR strain relative to those in WT strain, suggesting that ToxR repressed the transcription of scrA, scrG and vpa0198. lacZ fusion assay showed that ToxR was able to repress the promoter activities of scrA, scrG and vpa0198 in both V. parahaemolyticus and E. coli 100λpir. EMSA results showed that His-ToxR was able to bind to the regulatory DNA regions of scrA and scrG, but not to the regulatory DNA region of vpa0198. In conclusion, ToxR inhibited the production of c-di-GMP in V. parahaemolyticus via directly regulating the transcription of enzyme genes associated with c-di-GMP metabolism, which would be beneficial for V. parahaemolyticus to precisely control bacterial behaviors including biofilm formation.

Advance in the degradation of biodegradable plastics in different environments / 生物工程学报

With the continuously increasing demands of plastic products in the current society, the challenge of disposing plastic waste is constantly increasing, leading to the urgent need of mitigating plastic pollution. As a consequence, much attention has been paid to biodegradable plastics due to their degradability in a bio-active environment under certain conditions. Biodegradable plastics herald vast development potentials and considerable market prospects. The degradation of numerous types of biodegradable plastics will be affected by many factors. A thorough understanding of degradation mechanisms as well as functional microbial strains and enzymes is the key to comprehensive utilization and efficient treatment and disposal of biodegradable plastics. The article summarized the types, properties, advantages and disadvantages, and main applications of common biodegradable plastics. The degradation mechanisms, functional microbial strains and enzymes, as well as the degradation degree and duration under different environmental conditions, were also summarized. This review may help better understand the degradation of biodegradable plastics wastes.

Xintahua water extract improves the disease indexes of atherosclerosis model rats / 中国临床药理学与治疗学

AIM: To investigate the effect of water extract of Ziziphora clinopodioides Lam (WEZ) on improving atherosclerosis model rats. METHODS: Sixty SD rats were randomly selected and 50 rats of them were randomly selected for atherosclerosis model with high-fat emulsion and vitamin D3, and then randomly divided into atherosclerosis (AS) model group, low, medium, high WEZ group and the positive control group. After 8 weeks of drug intervention, the plasma of each group of rats was collected to detect total cholesterol (TC), triglyceride (TG), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and trimethylamine oxide (TMAO) level. The correlation between plasma TMAO and TNF-α and IL-6 levels in AS rats was detected. The aortic tissue-embedded sections of rats in each group were taken out to compare the aortic plaque area/aortic lumen area (PA/LA) ratio. RESULTS: Compared with the blank control group, the serum TC and TG levels of the AS model group increased significantly, and the difference was statistically significant (P<0.01). Compared with the AS model group, the serum TC and TG levels of the middle and high dose WEZ group and the positive control group were significantly decreased, and the difference was statistically significant (P<0.05). Compared with the blank control group, the serum TNF-α and IL-6 levels in the AS model group increased significantly, and the difference was statistically significant (P<0.01). Compared with the AS model group, the serum TNF-α and IL-6 levels of the high-dose WEZ group and the positive control group were significantly decreased, and the difference was statistically significant (P<0.05). Compared with the blank control group, the plasma TMAO level of rats in the AS model group increased significantly, and the difference was statistically significant (P<0.01). Compared with the AS model group, the plasma TMAO levels of rats in the high-dose WEZ group and the positive control group decreased significantly, and the difference was statistically significant (P<0.05). The analysis of the correlation between TMAO level and TNF-α/IL-6 level showed that TMAO level was positively correlated with TNF-α level (P=0.001, r=0.673), and positively correlated with IL-6 level (P=0.002, r= 0.646). Compared with the blank control group, the PA/LA ratio of the AS model group increased significantly, and the difference was statistically significant (P<0.01). Compared with the AS model group, the PA/LA ratio of rats in the medium and high dose WEZ group and the positive control group decreased significantly, and the difference was statistically significant (P<0.05). CONCLUSION: WEZ may regulate TMAO levels, down-regulate TNF-α and IL-6 levels, and reduces TC and TG levels, thereby improving AS, but its mechanism still needs further study.

Transcriptional regulation of pilABCD by OpaR in Vibrio parahaemolyticus / 中华微生物学和免疫学杂志

Objective:To study the transcriptional regulation of pilABCD by the master quorum sensing (QS) regulator OpaR in Vibrio parahaemolyticus. Methods:Total RNAs were extracted from the wild type (WT) and opaR mutant (Δ opaR) strain. Quantitative real-time PCR (qPCR) was employed to calculate the transcriptional variation of pilA (the first gene of pilABCD operon) between WT and Δ opaR. The regulatory DNA region of pilABCD was cloned into the corresponding restriction endonuclease sites of pHRP309 harboring a promoterless lacZ reporter gene. The recombinant pHRP309 plasmid was then transferred into WT and Δ opaR, respectively, to detect the β-galactosidase activity in cellular extracts using a β-Galactosidase Enzyme Assay System (Promega). The primer extension assay was applied to map the transcription start site of pilABCD using the total RNAs extracted from the WT strain as the template. The regulatory DNA region of pilABCD was amplified by PCR, and the over-expressed His-OpaR was purified under native conditions with nickel loaded HiTrap Chelating Sepharose columns (Amersham). Thereafter, the electrophoretic mobility shift assay (EMSA) was applied to analyze the DNA-binding activity of His-OpaR to the target DNA in vitro, and the DNase I footprinting assay was further employed to detect the DNA-binding sites of His-OpaR within the target DNA. Results:The results of qPCR and LacZ fusion assays showed that OpaR activated the transcription of pilABCD, leading to a gradual increase in the expression level of pilA with the extension of culture time. The primer extension assay detected only one transcription start site located at 155 bp upstream of pilA. The results of EMSA and DNase Ⅰ footprinting assays showed that His-OpaR protected two DNA regions located from -246 to -197 bp and -181 to -131 bp upstream of pilA. Conclusions:Vibrio parahaemolyticus OpaR activated the transcription of pilABCD in a direct manner.

Effects of hyperoxia exposure and small interfering RNA on the expressions of nuclear factor-erythroid 2-related factor 2 and NAD(P)H quinone oxidoreductase 1 enzyme in A549 cells and their relationship with apoptosis / 中华实用儿科临床杂志

Objective:To analyze the effect on the expressions of nuclear factor-erythroid 2-related factor 2(Nrf2) and NAD(P)H quinone oxidoreductase 1 enzyme (NQO1) in A549 cells exposed to hyperoxia and interfered by small interfering RNA, and to investigate the role of Nrf2 and NQO1 in hyperoxia-induced lung injury as well as their relationship with apoptosis.Methods:A549 cells were gained by serial sub cultivation in vitro and then randomly divided into 4 groups: the air group without interference ( group Ⅰ), the hyperoxia group without interference (group Ⅱ), the air group transfected with Nrf2 siRNA (group Ⅲ), and the hyperoxia group transfected with Nrf2 siRNA (group Ⅳ). The hyperoxia groups (Ⅱ, Ⅳ group) were continuously exposed to an atmosphere containing a high concentration of oxygen (950 mL/L O 2, 50 mL/L CO 2), while the air groups (group Ⅰ, Ⅲ) were still placed in the incubator with 50 mL/L CO 2. In the pre-experiment, cells were transduced with a mixture of siRNA-1, siRNA-2, and siRNA-3. Then the siRNA with the highest efficiency for repressing Nrf2 expression was used for subsequent experiments. The mRNA and protein expression levels of Nrf2 and NQO1 in the 4 groups were detected by quantitative real-time polymerase chain reaction (qPCR) and Western blot.The distribution of Nrf2, Kelch-like ECH-associated protein 1(Keap1) and antioxidant response element(ARE) proteins in A549 cells after interference with Nrf2 was analyzed by immunofluorescence and confocal laser scanning microscope, and the cell apoptosis of the 4 groups were observed. Results:(1) Nrf2 siRNA significantly down-regulated the mRNA expression of Nrf2 in the groups siRNA-1, siRNA-2 and siRNA-3, and the inhibition efficiency of group siRNA-1 was the highest (80.57%). (2) The re-lative mRNA expression levels of Nrf2 and NQO1 in the group Ⅱ were 4.553±0.498 and 5.866±0.582, respectively.The mRNA and protein expression of Nrf2 and NQO1 and the cell apoptosis rate [(21.67±0.75)%]in the hype-roxia group were significantly higher than those in the group Ⅰ (all P<0.01). (3) The relative mRNA expression levels of Nrf2 and NQO1 in the group Ⅳ were 0.937±0.057 and 0.789±0.058, respectively.Compared with the group Ⅱ, the mRNA and protein expression of Nrf2 and NQO1 in the group Ⅳ were significantly decreased, while the cell apoptosis rate [(35.83±0.42)%]was significantly increased (all P<0.01). Conclusions:The abnormal expression of Nrf2 and NQO1 in A549 cells induced by hyperoxia and siRNA interference suggests that Nrf2 and NQO1 are involved in the pathogenesis of hyperoxia induced lung injury.Nrf2 and NQO1 are possibly protective factors in the hyperoxia induced lung injury and apoptosis.

Medical implication in the Bible and its relevance to modern medicine / 中西医结合学报

The Holy Bible, as the root of Western civilization, has imposed great influence in the fields far beyond religion. In this thesis, the author intended to reveal the medical implication in the Holy Bible and its relevance to the modern medical science by exploring the biblical medical information and comparing it with the current medical theory and practice. The conclusion of the exploration is surprising yet inspiring: the Holy Bible, as an ancient religious book, contains rich medical information around themes such as sexual relations, dietary guidelines, hygiene, etc., which is not at odds, but in harmony with the modern medicine.

Effect of Potassium-rich Diet on Constipation for Hospitalized Elderly with Coronary Heart Disease / 中国康复理论与实践

@# Objective To observe the effect of potassium-rich diet on constipation for elderly patients with coronary heart disease (CHD) during hospitalization. Methods 100 elderly CHD patients were divided into treatment group (n=50) and control group (n=50). The treatment group drank orange juice 400 ml (about potassium 600 mg) per day, while the control group drank the same volume of water. Their defecation in 7 d was recorded. Results Compared with those in control group, the frequency of defecation increased (P<0.01), The Bleijenberg score and Bristol score both decreased (P<0.05) in the treatment group. There was no significant difference in incidence of major adverse cardiac events between these groups (P>0.05). Conclusion Potassium-rich diet plays an important role in prevention of constipation in elderly patients with CHD during hospitalization.

Risk factors analysis of upper gastrointestinal bleeding in elderly patients with aspirin and clopidogrel co-therapy / 中国医师进修杂志

Objective To explore the current occurrence of upper gastrointestinal bleeding (UGIB)in elderly patients and its possible risk factors and treatment program. Methods The clinical data of 758 elderly coronary heart disease patients with aspirin and clopidogrel co-therapy were collected, including past medical history,common condition,clinical medication,biochemical indicator and clinical turnover. The follow-up ended on the dates of a first occurrence of UGIB and death or after stopping co-therapy above 10 days. The follow-up time was 6 months. Results UGIB occurred in 48 patients,the occurrence rate was 6.3% (48/758). The occurrence rate of UGIB in proton pump inhibitor (PPI), H2-receptor antagonist (H2RA), gastric mucosa protective agents plus PPI, gastric mucosa protective agents plus H2RA and control was 3.7% (4/108),5.0% (12/240),1.4% (1/70),2.9% (3/102),11.8% (28/238). There were statistic differences in different methods (x2 = 18.63,P = 0.001). Conclusions The occurrence rate of UGIB combined with aspirin and clopidogrel co-therapy in elderly is high. Co-prescription with PPI and gastric mucosa protective agents is associated with a lower risk.

Morphine usage in elderly patients with acute decompensated heart failure / 中华老年医学杂志

Objective To explore morphine usage in emergency department (ED) and its effect on outcome in elderly patients with acute decompensated heart failure (ADHF) in a single Chinese center. Methods A prospective observational analysis was performed in elderly patients aged 65-99years with newly diagnosed ADHF, who were treated and admitted from ED of our hospital. The data including patients' demographic characters, past medical history, initial presentations and medication taking were collected and analyzed. According to using morphine or not, the patients were divided into two groups. The effects of morphine on mechanical ventilation, hospitalization stay and in-hospital mortality were also evaluated. Results The 82 patients were enrolled in this study, 52 males and 30females. In the 41 (50. 0%) patients using morphine (morphine usage group), the foregone incidence rates of coronary heart disease, type 2 diabetes mellitus and stroke were less, the levels of troponin T and random blood sugar were increased in morphine usage group than in non-morphine usage group.No other differences were found in initial presentations between the two groups. The patients often theophylline before morphine administration. And they had a higher prevalence of mechanical ventilation (95%CI: 1.22-7.41), but no differences were found in hospitalization stay and in-hospital mortality between the two groups. Conclusions Morphine is still as a common medicine in treatment of ADHF in ED. Morphine usage can increase prevalence of mechanical ventilation without influencing hospitalization stay and in-hospital mortality even in elderly ADHF patients. Morphine may be a safe medication in the rational treatment of early-stage ADHF in elderly patients with mechanical ventilation support.