A novel pbd gene cluster responsible for pyrrole and pyridine ring cleavage in Rhodococcus ruber A5.

Pyridine and pyrrole, which are regarded as recalcitrant chemicals, are released into the environment as a result of industrial manufacturing processes, posing serious hazards to both the environment and human health. However, the pyrrole degradation mechanism and the pyridine-degrading gene in Rhodococcus are unknown. Herein, a highly efficient pyridine and pyrrole degradation strain Rhodococcus ruber A5 was isolated. Strain A5 completely degraded 1000 mg/L pyridine in a mineral salt medium within 24 h. The pyridine degradation of strain A5 was optimized using the BoxBehnken design. The optimum degradation conditions were found to be pH 7.15, temperature 28.06 â„ƒ, and inoculation amount 1290.94 mg/L. The pbd gene clusters involved in pyridine degradation were discovered via proteomic analysis. The initial ring cleavage of pyridine and pyrrole in strain A5 was carried out by the two-component flavin-dependent monooxygenase PbdA/PbdE. The degradation pathways of pyridine and pyrrole were proposed by the identification of metabolites and comparisons of homologous genes. Additionally, homologous pbd gene clusters were found to exist in different bacterial genomes. Our study revealed the ring cleavage mechanisms of pyrrole and pyridine, and strain A5 was identified as a promising resource for pyridine bioremediation.

Mechanism of safener mefenpyr-diethyl biodegradation by a newly isolated Chryseobacterium sp. B6 from wastewater sludge and application in co-contaminated soil.

Safener mefenpyr-diethyl (MFD) was applied to cereal crops along with herbicides to improve herbicide selectivity for crops and weeds. However, the degradation mechanism of MFD in the environment remains unclear. One MFD-degrading bacterium, Chryseobacterium sp. B6, was isolated from activated sludge. According to Box-Behnken's optimal design, the degradation efficiency of MFD can reach 92% under conditions of pH 7.5, 30 °C, and a MFD concentration of 184 mg L-1. The degradation half-life experiment showed that a high concentration of MFD (300 mg L-1) inhibited the degradation ability of strain B6. Additionally, strain B6 was resistant to Ba2+, Cr3+, Li+, Zn2+, and Cu2+. The MFD degradation products of strain B6 were detected by GC/MS and its degradation pathway was proposed. MFD was first hydrolyzed by a hydrolase to an intermediate (RS)-1-(2,4-dichlorophenyl)-5-methyl-2-pyrazoline-5-carboxylic acid ethyl ester-3-carboxylic acid, and then further degraded by a decarboxylase to form the intermediate (RS)-1-(2,4-dichlorophenyl)-5-methyl-2-pyrazoline-5-carboxylic acid ethyl ester, finally, it is completely degraded by strain B6. Furthermore, strain B6 could effectively remove MFD from MFD-contaminated soil, and the half-life of MFD was also significantly reduced in MFD and Cu2+ co-contaminated soil after inoculating strain B6. To our knowledge, strain B6 was the first strain reported to degrade safener MFD, and this study provides a valuable candidate to remediate the co-contaminated soil with MFD and Cu2+.

Revealing the driving synergistic degradation mechanism of Rhodococcus sp. B2 on the bioremediation of pretilachlor-contaminated soil.

The pretilachlor has been widely used worldwide and has contaminated the environment for many years. The environmental fate of pretilachlor and its residues removal from the contaminated environment have attracted great concern. Reportedly, pretilachlor could partly be transformed to HECDEPA by Rhodococcus sp. B2. However, the effects of pretilachlor on soil bacterial communities and its complete metabolic pathway remain unknown. Herein, we investigated the mechanism of driving synergistic degradation of pretilachlor by strain B2 in the soil. The results revealed that pretilachlor showed a negative effect on bacterial communities and caused significant variations in the community structure. Strain B2 showed the ability to remediate the pretilachlor-contaminated soils and network analysis revealed that it may drive the enrichment of potential pretilachlor-degrading bacteria from the soil. The soil pretilachlor degradation may be facilitated by the members of the keystone families Comamonadaceae, Caulobacteraceae, Rhodospirillaceae, Chitinophagaceae, and Sphingomonadaceae. Meanwhile, Sphingomonas sp. M6, a member of the Sphingomonadaceae family, has been isolated from the strain B2 inoculation sample soil. The co-culture, comprising strain M6 and B2, could synergistic degrade pretilachlor within 30 h, which is the highest degradation rate. Strain M6 could completely degrade the HECDEPA via CDEPA and DEA. In the soil, a comparable pretilachlor degradation pathway may exist. This study suggested that strain B2 had the potential to drive the remediation of pretilachlor-contaminated soils.

One-Pot Biosynthesis of l-Aspartate from Maleic Anhydride via a Thermostable Dual-Enzyme System under High Temperature.

l-Aspartate is an important chemical in the food and pharmaceutical industries. Herein, a dual-enzyme system was constructed to synthesize l-aspartate from maleic anhydride at 50 °C, which can reduce the byproduct production. Maleate transformed from maleic anhydride in the solution was converted into l-aspartate via fumarate catalyzed by maleate isomerase (MaiA) and thermostable aspartase (AspB), respectively. Because MaiA is a rate-limiting enzyme, enzyme activities of various MaiAs were compared, and the efficient and thermostable maleate isomerase AaMaiA from Alicyclobacillus acidoterrestris was chosen. The Kcat/Km value of AaMaiA was 264.4 mM-1 min-1. AaMaiA and AspB were coexpressed in E. coli to produce l-aspartate. To improve the l-aspartate production rate, the ribosome binding site (RBS) sequence located upstream of AaMaiA was optimized and the Tat signal peptide was fused with AaMaiA. The conversion rate was 96% within 60 min, and the intermediate was not detected, the possible reason of which is that high temperature inhibits the activity of bacterial endogenous enzymes, but functional enzymes remain active. Cells from fermentation produced 243.6 g/L (1.83 M) of l-aspartate with a 2 M substrate. Our study revealed an effective method to produce l-aspartate without using gene knockout and provided a strategy for l-aspartate production in the industrial field.

Application of distant live broadcast in clinical anesthesiology teaching.

OBJECTIVE: To explore the application value and effect of distance live broadcast in Clinical Anesthesiology teaching. METHODS: Undergraduate students of year 2017 who majored in Anesthesiology at the Wannan Medical College (China) were chosen as the study subjects. According to the different teaching methods, the students were divided into two groups: 59 in the traditional teaching group (control group) and 61 in the traditional teaching combined with distant live broadcasting teaching group (observation group). The teaching feedback, students' satisfaction, and the theory and skill scores of the course were compared between the two groups. RESULTS: The teaching feedback in the observation group was better than that in the control group (P<0.05). The students' satisfaction rate with teaching and the theory and skill learning score in the observation group were higher than those of the control group (P<0.05). CONCLUSION: Traditional teaching combined with distant live broadcast teaching has achieved good results in clinical anesthesiology teaching, improved the overall quality of teaching, and has high clinical teaching value.

Research progress of ulinastatin in the treatment of liver diseases.

Ulinastatin (UTI) is a trypsin inhibitor observed in urine. UTI can treat some diseases by inhibiting the broad-spectrum hydrolysis activity of various enzymes and other pharmacological effects. UTI can widely treat pancreatitis, systemic multiple organ dysfunction syndrome, circulatory failure, and toxic shock clinically. The liver is a major metabolic organ of the human body. Various biological metabolic reactions require the liver's participation. When various physical and chemical factors drive the body, it will damage the liver to varying degrees. As a clinically effective drug, UTI is also known to treat some liver diseases. This article mainly describes UTI's research progress in treating septic liver injury, hepatitis, liver fibrosis, autoimmune liver disease with liver failure, and liver ischemia-reperfusion injury.

Effect of sleep deprivation on general anesthesia in rats.

OBJECTIVE: To explore the effects of sleep deprivation on perioperative general anesthesia in rats. METHODS: 45 healthy male Sprague-Dawley (SD) rats were randomly divided into 3 groups, the control group (Group A), the anesthesia group (Group B) and the sleep deprivation anesthesia group (Group C), 15 in each group. The sleep deprivation model was established by improving multi-platform water environment method. The group B and C were received propofol 80 mg/kg by intraperitoneally, the group A was given the same dose of normal saline. The EEG in each group was measured. The GABAa R-ß3 protein in cerebral cortex was detected by Western Blot. The rats were treated with Brennan incision, and the changes of thermal pain sensitive (PWL) and open field behavior were measured in each group. RESULTS: In group C, the δ band of brainwave of EEG increased significantly, the disappearance time of righting reflex shortened significantly, the recovery time prolonged significantly, the GABAa R-ß3 protein was significantly increased, and the time of passing through the central area before operation was significantly decreased. CONCLUSION: Sleep deprivation can significantly inhibit the electrical activity of rat cerebral cortex induced by propofol, up-regulating the GABAa R-ß3 protein in cortex.

Angiotensin II system in the nucleus tractus solitarii contributes to autonomic dysreflexia in rats with spinal cord injury.

BACKGROUND: Autonomic dysreflexia (AD) is a potentially life-threating complication after spinal cord injury (SCI), characterized by episodic hypertension induced by colon or bladder distension. The objective of this study was to determine the role of impaired baroreflex regulation by the nucleus tractus solitarii(NTS) in the occurrence of AD in a rat model. METHODS: T4 spinal cord transection animal model was used in this study, which included 40 Male rats Colorectal distension (CD) was performed to assess AD and compare the changes of BP, HR, and BRS, six weeks after operation. After that, SCI rats with successfully induced AD were selected. Losartan was microinjected into NTS in SCI rats, then 10, 30, 60 minutes later, CD was performed to calculate the changes of BP, HR, and BRS in order to explicit whether Ang II system was involved in the AD occurrence. Ang II was then Intra-cerebroventricular infused in sham operation rats with CD to mimic the activation of Ang II system in AD. Finally, the level of Ang II in NTS and colocalization of AT1R and NMDA receptor within the NTS neurons were also detected in SCI rats. RESULTS: Compared with sham operation, SCI significantly aggravated the elevation of blood pressure (BP) and impaired baroreflex sensitivity (BRS) induced by colorectal distension; both of which were significantly improved by microinjection of the angiotensin receptor type I (AT1R) antagonist losartan into the NTS. Level of angiotensin II (Ang II) in the NTS was significantly increased in the SCI rats than sham. Intracerebroventricular infusion of Ang II also mimicked changes in BP and BRS induced by colorectal distension. Blockade of baroreflex by sinoaortic denervation prevented beneficial effect of losartan on AD. CONCLUSION: We concluded that the activation of Ang II system in NTS may impair blood pressure baroreflex, and contribute to AD after SCI.

TLR4-dependent internalization of CX3CR1 aggravates sepsis-induced immunoparalysis.

Sepsis, the most severe manifestation of infection, poses a major challenge to health-care systems around the world. Limited ability to clean and remove the pathogen renders difficulty in septic patients to recover from the phase of immunoparalysis. The present study found the vital role of CX3CR1 internalization on sepsis-induced immunoparalysis. A mouse model with cecal ligation and puncture (CLP) and cell model with lipopolysaccharides (LPS) were employed to explore the relationship between CX3CR1 internalization and septic immunoparalysis. Immunoparalysis model in mice was established 4 days after CLP with significantly decreased proinflammatory cytokines. Flow cytometry analysis found a decreased surface expression of CX3CR1 during immunoparalysis, which was associated with reduced mRNA level and increased internalization of CX3CR1. G-protein coupled receptor kinase 2 (GRK2) and ß-arrestin2 were significantly increased during septic immunoparalysis and involved in the internalization of CX3CR1. TLR4-/- or TLR4 inhibitor-treated macrophages exhibited an inhibited expression of GRK2 and ß-arrestin2, along with reduced internalization of CX3CR1. Moreover, the knockdown of GRK2 and ß-arrestin2 inhibited the internalization of CX3CR1 and led to a higher response on the second hit, which was associated with an increased activation of NF-κB. The critical association between internalization of CX3CR1 and immunosuppression in sepsis may provide a novel reference for clinical therapeutics.

Efficacy of dexmedetomidine on postoperative nausea and vomiting: a meta-analysis of randomized controlled trials.

PURPOSE: Postoperative nausea and vomiting (PONV) is a frequent complication in postoperative period. The aim of the current meta-analysis was to assess the efficacy of dexmedetomidine on PONV. METHODS: Two researchers independently searched PubMed, Embase and Cochrane Central Register of Controlled Trials for randomized controlled trials (RCTs). The meta-analysis was performed with Review Manager. RESULTS: Eighty-two trials with 6,480 patients were included in this meta-analysis. Dexmedetomidine reduced postoperative nausea (Risk Ratio (RR) = 0.61, 95% confidence interval (CI): 0.50 to 0.73) and vomiting (RR = 0.48, 95% CI: 0.36 to 0.64) compared with placebo, with an effective dose of 0.5 ug/kg (RR = 0.46, 95% CI: 0.34 to 0.62) and 1.0 ug/kg (RR = 0.29, 95% CI: 0.12 to 0.75), respectively. The antiemetic effect can only be achieved intravenously, not epidurally or intrathecally. The efficacy of dexmedetomidine was similar to that of widely used agents, such as propofol, midazolam etc., but better than opioid analgesics. Moreover, application of dexmedetomidine reduced intraoperative requirement of fentanyl (Standard Mean Difference = -1.91, 95% CI: -3.20 to -0.62). CONCLUSIONS: The present meta-analysis indicates that dexmedetomidine shows superiority to placebo, but not to all other anesthetic agents on PONV. And this efficacy may be related to a reduced consumption of intraoperative opioids.

Efficacy of dexmedetomidine on postoperative nausea and vomiting: a meta-analysis of randomized controlled trials.

PURPOSE: Postoperative nausea and vomiting (PONV) is a frequent complication in postoperative period. The aim of the current meta-analysis was to assess the efficacy of dexmedetomidine on PONV. METHODS: Two researchers independently searched PubMed, Embase and Cochrane Central Register of Controlled Trials for randomized controlled trials (RCTs). The meta-analysis was performed with Review Manager. RESULTS: Eighty-two trials with 6,480 patients were included in this meta-analysis. Dexmedetomidine reduced postoperative nausea (Risk Ratio (RR) = 0.61, 95% confidence interval (CI): 0.50 to 0.73) and vomiting (RR = 0.48, 95% CI: 0.36 to 0.64) compared with placebo, with an effective dose of 0.5 µg/kg (RR = 0.46, 95% CI: 0.34 to 0.62) and 1.0 µg/kg (RR = 0.29, 95% CI: 0.12 to 0.75), respectively. The antiemetic effect can only be achieved intravenously, not epidurally or intrathecally. The efficacy of dexmedetomidine was similar to that of widely used agents, such as propofol, midazolam etc., but better than opioid analgesics. Moreover, application of dexmedetomidine reduced intraoperative requirement of fentanyl (Standard Mean Difference = -1.91, 95% CI: -3.20 to -0.62). CONCLUSIONS: The present meta-analysis indicates that dexmedetomidine shows superiority to placebo, but not to all other anesthetic agents on PONV. And this efficacy may be related to a reduced consumption of intraoperative opioids.

Efficacy of traditional Chinese medicine on sepsis: a systematic review and Meta-Analysis.

BACKGROUND: Traditional Chinese medicine (TCM) has been used for treatment of sepsis in China, but results still remain equivocal. To evaluate the safety and efficacy of TCM for sepsis, we conducted this Meta-analysis. METHODS: Databases searched included randomized controlled trials (RCTs) published in PubMed, Embase and Cochrane Central Register of Controlled Trials (CENTRAL) (up to December 2014). The studies included used routine therapy treating sepsis in the control group and TCM was added on that basis in the experimental group. Methodological quality was assessed by Cochrane criteria for risk of bias. RESULTS: Ten RCTs with 691 participants were identified and analyzed. In the meta-analysis, TCM plus routine therapy reduced the 28-day mortality compared to routine therapy alone, [RR = 0.67; 95% CI: 0.51~0.87; P = 0.002]; The decrease in length of ICU-stay [MD = -1.82; 95% CI: -2.60~-1.04; P<0.00001]; Acute physiology and chronic health evaluation system (APACHE II) score [MD = -2.95; 95% CI: -3.99~-1.91; P<0.00001]; Serum inflammatory factors concentration after treatment [SMD = -0.50; 95% CI:-0.68~-0.33; P<0.00001], including TNF-α [SMD = -0.61; 95% CI: -0.85~-0.38; P<0.00001] and IL-6 [SMD = -0.40; 95% CI: -0.75~-0.04; P = 0.03] in subgroup analysis all had statistical significance. CONCLUSION: Addition of TCM has better effects in participants with sepsis, while more high-quality studies are needed to draw firm conclusion.