Mechanism of extracellular electron transport and reactive oxygen mediated Sb(III) oxidation by Klebsiella aerogenes HC10.

Microbial oxidation and the mechanism of Sb(III) are key governing elements in biogeochemical cycling. A novel Sb oxidizing bacterium, Klebsiella aerogenes HC10, was attracted early and revealed that extracellular metabolites were the main fractions driving Sb oxidation. However, linkages between the extracellular metabolite driven Sb oxidation process and mechanism remain elusive. Here, model phenolic and quinone compounds, i.e., anthraquinone-2,6-disulfonate (AQDS) and hydroquinone (HYD), representing extracellular oxidants secreted by K. aerogenes HC10, were chosen to further study the Sb(III) oxidation mechanism. N2 purging and free radical quenching showed that oxygen-induced oxidation accounted for 36.78% of Sb(III) in the metabolite reaction system, while hydroxyl free radicals (·OH) accounted for 15.52%. ·OH and H2O2 are the main driving factors for Sb oxidation. Radical quenching, methanol purification and electron paramagnetic resonance (EPR) analysis revealed that ·OH, superoxide radical (O2•-) and semiquinone (SQ-•) were reactive intermediates of the phenolic induced oxidation process. Phenolic-induced ROS are one of the main oxidants in metabolites. Cyclic voltammetry (CV) showed that electron transfer of quinone also mediated Sb(III) oxidation. Part of Sb(V) was scavenged by the formation of the secondary Sb(V)-bearing mineral mopungite [NaSb(OH)6] in the incubation system. Our study demonstrates the microbial role of oxidation detoxification and mineralization of Sb and provides scientific references for the biochemical remediation of Sb-contaminated soil.

Toxicity of common biocides used in aquaculture to embryos and larvae of Brachymystax tsinlingensis Li.

Brachymystax tsinlingensis Li is a threatened fish species endemic to China. With the problems of environmental factors and seeding breeding diseases, it is important to further improve the efficiency of seeding breeding and the basis of resource protection. This study investigated the acute toxicity of copper, zinc and methylene blue (MB) on hatching, survival, morphology, heart rate (HR) and stress behaviour of B. tsinlingensis. Eggs (diameter: 3.86 ± 0.07 mm, weight: 0.032 ± 0.004 g) of B. tsinlingensis were selected randomly from artificial propagation and developed from eye-pigmentation-stage embryos to yolk-sac stage larvae (length: 12.40 ± 0.02 mm, weight: 0.03 ± 0.001 g) and exposed to different concentrations of Cu, Zn and MB for 144 h in a series of semi-static toxicity tests. The acute toxicity tests indicated that the 96-h median lethal concentration (LC50 ) values of the embryos and larvae were 1.71 and 0.22 mg l-1 for copper and 2.57 and 2.72 mg l-1 for zinc, respectively, whereas the MB LC50 after 144-h exposure for embryos and larvae were 67.88 and 17.81 mg l-1 , respectively. The safe concentrations of copper, zinc and MB were 0.17, 0.77 and 6.79 mg l-1 for embryos and 0.03, 0.03 and 1.78 mg l-1 for larvae, respectively. Copper, zinc and MB treatments with concentrations greater than 1.60, 2.00 and 60.00 mg l-1 , respectively, led to a significantly low hatching rate and significantly high embryo mortality (P < 0.05), and copper and MB treatments with concentrations greater than 0.2 and 20 mg l-1 led to significantly high larvae mortality (P < 0.05). Exposure to copper, zinc and MB resulted in developmental defects, including spinal curvature, tail deformity, vascular system anomalies and discolouration. Moreover, copper exposure significantly reduced the HR of larvae (P < 0.05). The embryos exhibited an obvious change in behaviour, converting from the normal behaviour of emerging from the membrane head first to emerging tail first, with probabilities of 34.82%, 14.81% and 49.07% under copper, zinc and MB treatments, respectively. The results demonstrated that the sensitivity of yolk-sac larvae to copper and MB was significantly higher than that of embryos (P < 0.05) and that B. tsinlingensis embryos or larvae might be more resistant to copper, zinc and MB than other members of the Salmonidae family, which benefits their resource protection and restoration.

SGK1, a Critical Regulator of Immune Modulation and Fibrosis and a Potential Therapeutic Target in Chronic Graft-Versus-Host Disease.

Patients with severe chronic graft-versus-host disease (cGVHD) always experience debilitating tissue injury and have poorer quality of life and shorter survival time. The early stage of cGVHD is characterized by inflammation, which eventually leads to extensive tissue fibrosis in various organs, such as skin and lung, eventually inducing scleroderma-like changes and bronchiolitis obliterans syndrome. Here we review the functions of serum/glucocorticoid regulated kinase 1 (SGK1), a hub molecule in multiple signal transduction pathways and cell phosphorylation cascades, which has important roles in cell proliferation and ion channel regulation, and its relevance in cGVHD. SGK1 phosphorylates the ubiquitin ligase, NEDD4, and induces Th cells to differentiate into Th17 and Th2 phenotypes, hinders Treg development, and promotes inflammatory fibrosis. Phosphorylation of NEDD4 by SGK1 also leads to up-regulation of the transcription factor SMAD2/3, thereby amplifying the fibrosis-promoting effect of TGF-ß. SGK1 also up-regulates the inflammatory transcription factor, nuclear factor-κB (NF-κB), which in turn stimulates the expression of multiple inflammatory mediators, including connective tissue growth factor. Overexpression of SGK1 has been observed in various fibrotic diseases, including pulmonary fibrosis, diabetic renal fibrosis, liver cirrhosis, hypertensive cardiac fibrosis, peritoneal fibrosis, and Crohn's disease. In addition, SGK1 inhibitors can attenuate, or even reverse, the effect of fibrosis, and may be used to treat inflammatory conditions and/or fibrotic diseases, such as cGVHD, in the future.

Immobilization mechanism of antimony by applying zirconium-manganese oxide in soil.

Antimony (Sb) accumulation in soil poses great potential risk to ecological environment, and its mobilization, transformation and bioavailability are controlled by its fractions and species. Hence, it is important to develop functional materials with both adsorption and oxidation that achieve detoxification and control the mobilization of Sb. In this study, the synthesized zirconium­manganese oxide (ZrMn) could extremely promoted the transformation of antimonite [Sb(III)] to antimonate [Sb(V)], induced the bioavailable Sb shift to well-crystallized (hydr)oxides of Mn and residual fractions, and further reduced mobility and bioavailability Sb in soil. The sorption of ZrMn to Sb(III) and antimonate Sb(V) were affected by interfering ions, and to Sb(III) was a heterogeneous adsorption process. Spectroscopic characterization of XPS and FTIR suggested exchange between the hydroxyl groups and Sb was crucial in its retain and forming an electronegative inner-sphere mononuclear or binuclear bridging compound. The oxidation induced the transformation of Mn species in ZrMn, generated Mn(II) and Mn(III) exposing more reactive sites conducive to oxidation and adsorption, thus Mn oxides has a higher adsorption capacity for Sb(III). However, the Zr oxides of ZrMn presented adsorption rather than oxidation. The application of ZrMn could realize the dual effect of Sb oxidation detoxification and adsorption immobilization in soil, which provided references for Sb contaminated soil remediation.

Sb(III) resistance mechanism and oxidation characteristics of Klebsiella aerogenes X.

Resistant bacteria are potential natural materials for the bioremediation of soil metalloid pollution. A strain isolated from farmland soil chronically exposed to Sb was identified as K. aerogenes X with high antimonite [Sb(III)] tolerance and oxidation ability. The resistance mechanism of K. aerogenes X and its extracellular polymeric substances (EPS), antioxidant enzymes, and oxidation characteristics in Sb(III) stress were investigated in this study by stress incubation experiments and FTIR. The biotoxicity of Sb was limited by the binding of the organic compounds in EPS, and the anionic functional groups (e.g., amino, carboxyl and hydroxyl groups, etc.) present in the cell envelope were the components primarily responsible for the metalloid-binding capability of K. aerogenes X. The K. aerogenes X can oxidize Sb(III), and its metabolites induce changes in reactive oxygen species (ROS), catalase (CAT), total superoxide dismutase (SOD) and glutathione s-transferase (GSH-S) activity, indicating that the resistance mechanisms of K. aerogenes X are mediated by oxidative stress, EPS restriction and cell damage. Oxidation of Sb(III) is driven by interactions in intracellular oxidation, cell electron transport, extracellular metabolism including proteins and low molecular weight components (LMWs). LMWs (molecular weight <3 kDa) are the main driving factor of Sb(III) oxidation. In addition, Sb resistance genes arsA, arsB, arsC, arsD and acr3 and potential oxidation gene arsH were identified in K. aerogenes X. Owing to its natural origin, high tolerance and oxidation ability, K. aerogenes X could serve as a potential bioremediation material for the mitigation of Sb(III) in contaminated areas.

Remediation of Soil in a Deserted Arsenic Plant Site Using Synthesised MgAlFe-LDHs.

Layered double hydroxides (LDHs) are promising soil contamination amendment agents for its efficient absorbing abilities. However, the application of LDHs in remediation of heavy metal contaminated soil are to be developed. In this study, we synthesized MgAlFe-LDHs by introducing Fe3+ into interlayer of the MgAl-LDHs using co-precipitation method. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR) and scanning electron microscope (SEM) were employed to characterized the micro structure of MgAlFe-LDHs. And then pot incubation and pilot experiments were conducted to investigate the heavy metal removal efficiencies of MgAlFe-LDHs and its potential being applicated in As contaminated soil amendment from a deserted arsenic plant site. Incubation experiments showed that the MgAlFe-LDHs had a higher removal efficiency on arsenic contaminated soil compared to other agents. And the results of pilot experiments indicated that the MgAlFe-LDHs can immobilize up to 90% of the As in soil with 5% (w/w) addition. Based on the results above, MgAlFe-LDHs are promising materials amending the heavy metal contaminated soil with practical application value.

Remediation of Cd, Pb and as Co-contaminated Paddy Soil by Applying Different Amendments.

The current study investigated the efficiency of sepiolite (SE), sodium humate (HS), microbial fertilizer (JF) and SE combined with JF/HS in a ratio of 2:1 (w/w) (JF-2SE and HS-2SE) on Cd, Pb and As bioavailability in field trials with rice (Oryza sativa L.). The results showed that all the amendments remarkably decreased (p < 0.05) the contents of available Cd and available Pb in soil. Only JF-2SE treatment reduced available As concentration in soil. All the amendments were found to effectively reduce (p < 0.05) the contents of As in brown rice. Both JF-2SE and HS-2SE co-applications reduced the concentrations of Cd in brown rice to 0.108 and 0.135 mg kg-1, and that of Pb reduced to 0.2 and 0.175 mg kg-1, which met the national standard limit of China. Thus, the co-application of JF/HS-2SE can be a promising remediation strategy in Cd, Pb and As co-contaminated paddy soil.

Changes in bladder function with time following cystostomy in rats.

AIMS: To investigate bladder function patterns following cystostomy and determine the best time window for cystometric evaluation of bladder function in conscious rats. MATERIALS AND METHODS: Cystostomy was performed in rats of the first seven groups; thereafter, cystometry was performed in the designed time interval. Noncystostomy rats of group 8 voided freely as control. Basal bladder pressure (Pves.basal ), maximum bladder pressure (Pves.max ), bladder threshold pressure (Pves.thre ), voiding interval (VI), bladder contraction duration (CD), bladder compliance (ΔC), voided volume (VV), postvoiding residual urine (PVR), and bladder capacity (BC) were recorded and compared with cystostomy groups, with VV, PVR, BC compared with the control values. Bladders were collected after the urodynamic study for weighing, hematoxylin-eosin, and Masson staining to investigate pathological changes. RESULTS: Pves.basal , Pves.max , and Pves.thre trended downward, while BC, VI, VV, and ΔC trended upward on days 1 to 5 postcystostomy. BC and VV significantly decreased on days 1 to 3 postcystostomy compared with control values; on days 5 to 15 postcystostomy, Pves.basal , Pves.max , Pves.thre , VI, VV, BC, and PVR were stable, and BC, VV, and PVR showed no significant differences from the control values. However, on day 21 postcystostomy, BC increased significantly compared with the controls. Bladder weight increased in the cystostomy groups compared with the controls. Pathological analysis showed severe acute bladder inflammation on days 1 to 3, mild inflammation on days 5 to 15, and increased collagen deposition in bladder tissue on day 21 postcystostomy. CONCLUSION: Cystometric evaluation of bladder function in conscious rats is best performed on days 5 to 15 postcystostomy.

Prevalence of Spina Bifida Occulta and Its Relationship With Overactive Bladder in Middle-Aged and Elderly Chinese People.

PURPOSE: To investigate the prevalence of spina bifida occulta (SBO) and its relationship with the presence of overactive bladder (OAB) in middle-aged and elderly people in China. METHODS: A cross-sectional community-based survey was carried out at 7 communities in Zhengzhou City, China from December 15, 2013 to June 10, 2014, where residents aged over 40 years were randomly selected to participate. All of the participants underwent lumbosacral radiographic analysis and relevant laboratory tests. A questionnaire including basic information, past medical history and present illness, and the OAB symptom score was filled out by all participants. Chi-square tests and logistic regression were used for data analysis with a P-value of <0.05 denoting statistical significance. RESULTS: A total of 1,061 subjects were qualified for the final statistical analysis (58.8±11.7 years; male, 471 [44.4%]; female, 590 [55.6%]). The overall prevalence of SBO was 15.1% (160 of 1,061): 18.3% (86 of 471) in men and 12.5% (74 of 590) in women. Among these subjects, 13.7% (145 of 1,061) had OAB: 13.2% (62 of 471) in men and 14.1% (83 of 590) in women. The results of logistic regression showed that age, SBO, history of cerebral infarction (HCI), and constipation were risk factors for OAB (P<0.05), while sex, history of childhood enuresis (HCE), body mass index (BMI), and diabetes mellitus (DM) were not (P>0.05). In men, age, SBO, and constipation were risk factors for OAB (P<0.05), while HCE, BMI, DM, HCI, and benign prostate hyperplasia were not (P>0.05). In women, age, SBO, and HCI were risk factors for OAB (P<0.05), while HCE, BMI, DM, vaginal delivery, and constipation were not (P>0.05). CONCLUSIONS: The prevalence of SBO is high and it is related to OAB in middle-aged and elderly people in China.

Prevalence of Spina Bifida Occulta and Its Relationship With Overactive Bladder in Middle-Aged and Elderly Chinese People / 대한배뇨장애요실금학회지

PURPOSE: To investigate the prevalence of spina bifida occulta (SBO) and its relationship with the presence of overactive bladder (OAB) in middle-aged and elderly people in China. METHODS: A cross-sectional community-based survey was carried out at 7 communities in Zhengzhou City, China from December 15, 2013 to June 10, 2014, where residents aged over 40 years were randomly selected to participate. All of the participants underwent lumbosacral radiographic analysis and relevant laboratory tests. A questionnaire including basic information, past medical history and present illness, and the OAB symptom score was filled out by all participants. Chi-square tests and logistic regression were used for data analysis with a P-value of 0.05). In men, age, SBO, and constipation were risk factors for OAB (P0.05). In women, age, SBO, and HCI were risk factors for OAB (P0.05). CONCLUSIONS: The prevalence of SBO is high and it is related to OAB in middle-aged and elderly people in China.

Treatment of femoral neck fracture with percutaneous compression plate: preliminary results in 74 patients.

OBJECTIVE: The purpose of this study was to present the surgical technique and clinical results of percutaneous compression plate (PCCP) for the treatment of femoral neck fractures. METHODS: Between December 2010 and April 2013, 74 consecutive patients with 74 femoral neck fractures were treated by closed reduction and PCCP implants in our university hospital. Their mean age was 51.3 years (range, 15-83 years); 38 (51.4%) were male and 46 (62.2%) of the fractures were on the left. The patients' clinical and radiographic data were analyzed retrospectively. RESULTS: There were 45 undisplaced (60.8%) and 29 displaced fractures (39.2%). Eight patients (10.8%) were lost to follow-up. The mean duration of follow-up was 18.8 months for the remaining 66 patients. At the last follow-up, mean Harris hip score was 92.9 (range, 75-100), and 65 patients (98.5%) had excellent and good outcomes. Sixty-five patients (98.5%) were able to walk independently and one (1.5%) with walking-sticks. The mean time to clinical fracture healing was 3.9 months. There were no cases of nonunion. Two patients (3.0%) had delayed union and two (3.0%) developed avascular necrosis, one of 29 (3.7%) with a displaced fracture and one of 45 (2.6%) with an undisplaced fracture. There were no other complications or prosthetic replacement. CONCLUSIONS: PCCP is a stable internal fixation device that resists axial and rotational stresses. Our PCCP procedure has a low incidence of nonunion and avascular necrosis.

[Changes and significance of soluble CD 163 in sepsis and severe sepsis in children].

OBJECTIVE: To investigate the changes of serum soluble CD 163 (sCD 163) level, to assess the severity of critical illness and to evaluate the immune status of sepsis or severe sepsis in children. METHOD: A prospective study was conducted. The sCD 163 was determined in 50 cases with sepsis or severe sepsis in pediatric intensive care unit (PICU) and 23 cases of age- and gender-matched healthy children were enrolled as control during the period from April 2010 to March 2011. Double-antibody sandwich ELISA was used for sCD 163 measurement. The relationship with sCD 163 level and disease severity score (pediatric critical illness score, PCIS; and pediatric risk of mortality III, PRISM III), lymphocyte subsets, C-reactive protein (CRP), tumor necrosis factor α (TNFα) were analyzed. RESULT: The sCD 163 in sepsis/severe sepsis groups (171.04 ± 177.85) mg/L was significantly higher than that in control group (44.19 ± 86.48) mg/L (P < 0.01).sCD 163 in sepsis group [(105.32 ± 145.87) mg/L] was significantly lower than that of severe sepsis group [(233.32 ± 171.78) mg/L] (P < 0.05). sCD 163 level was significantly higher in lower PCIS score patients. (P < 0.01). The sCD 163 levels was higher in PRISM III ≥ 10 than the PRISM III < 10 group. The sCD 163 levels were higher in death group than the survival group. The sCD 163 was negatively correlated with CD4 +, CD4 +/CD8 + (R = -0.820, P < 0.05; R = -0.839, P < 0.01). CONCLUSION: Detection of sCD 163 was helpful in predicting the severity of sepsis and severe sepsis, and sCD 163 may reflect the immune status of critically ill children with sepsis.

[Efficacy of continuous blood purification on rescue therapy of the critically ill children with acute lung injury and acute respiratory distress syndrome].

OBJECTIVE: To investigate the efficacy of continuous blood purification(CBP) in the treatment of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) in children. METHODS: One hundred and forty seven cases of ALI/ARDS were hospitalized to our pediatric intensive care unit, and 32 cases were treated with continuous blood purification (CBP) from June, 2006 to May, 2011. The model for CBP was continuous veno-venous hemofiltration dialysis (CVVHDF). CBP treatment persisted for at least 8 hours and replacement + dialysis fluid dose was 35 - 100 ml/(kg·h). The clinical outcome measures included the mortality rate at 28th day, respiratory index (FiO2/PO2), dynamic lung compliance (Cdyn), arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), mechanical ventilation parameters, vasoactive drug dose and lung X-ray changes. RESULTS: In totally 147 cases of ALI/ARDS, 89 cases (60.5%) were male and 58 (39.5%) were female, mean age was (43.4 ± 36.7) months. Death occurred in 54 cases, the total mortality was 36.7%. The cause of ALI/ARDS was mainly severe pneumonia, severe sepsis, and leukemia or tumor diseases. There were significant differences in severity of illness between the CBP treatment group and non-CBP treatment group on Pediatric risk of score mortality (PRISM) III score (15.3 vs. 12.7, P < 0.05) and pediatric critical illness score (66.8 ± 19.3 vs. 74.6 ± 17.7, P < 0.05). The average duration of CBP treatment was 52 hours (12 hours to 232 hours). PaO2/FiO2 and Cdyn were improved after 2 hours CBP treatment compared with those before CBP treatment (P < 0.05), mechanical ventilation parameters including fraction of inspired oxygen (FiO2), peak inspiratory pressure (PiP) and positive end expiratory pressure (PEEP) were reduced. The use of vasoactive drugs in patients with MODS and shock gradually declined. The average ventilator-free days of the two groups did not show significant difference (P > 0.05). The mortality on CBP treatment group and non-treatment group were 37.5% and 36.5%, respectively, the difference was not significant (P > 0.05). CONCLUSION: CBP adjuvant treatment for ALI/ ARDS could reduce pulmonary edema, improve PaO2/FiO2 and Cdyn, and improve mechanical ventilation parameters. CBP may be a very promising treatment for ALI/ARDS in children.

Glucocorticoid receptor expression on acute lung injury induced by endotoxin in rats.

BACKGROUND: In cases of severe sepsis and septic shock, a series of pathophysiological changes lead to multiple organ dysfunction syndrome. This study aimed to investigate the expression of glucocorticoid receptor mRNA in the rat lung following endotoxin (LPS) induced shock. METHODS: Totally 56 SD rats were randomly divided into 4 groups: LPS shock group (n=16), LPS+vasoactive intestinal peptide group(VIP) group, (n=16), LPS+VIP+ glucocorticoid (GC) group, (n=16),and control group (n=8). LPS shock was induced by intravenous injection of LPS (10 mg/kg) in rats. Within 15 minutes after LPS injection, rats in the treatment groups received VIP (5 nmol/kg) or VIP and methylprednisolone (3 mg/kg). The control group was given normal saline instead of LPS. The rats of the four groups were sacrificed at 6 hours,24 hours after injection respectively, and the lung tissues were collected. Pathological changes of the lungs were examined by light microscopy and electron microscopy. GRmRNA expression in the lung tissues was evaluated by RT-PCR. RESULTS: In the LPS shock group, lung histopathology demonstrated destruction of the alveolar space,widening of the inter-alveolar space, inflammatory cell infiltration and interstitial edema. However,pathological changes in the LPS+ VIP group and LPS+ VIP+GC group were milder than those in the LPS shock group. Six hours after LPS injection, GR mRNA expression was down-regulated in the LPS group (0.72± 0.24) and LPS+ VIP group (0.88±0.27) (P<0.05) as compared with the control group (1.17±0.22). The LPS shock group showed a more significant down-regualtion than the LPS+VIP group, but the difference was not statistically significant (P>0.05). In contrast, GRmRNA expression in the LPS+ VIP+GC group was significantly up-regulated at 6 hours and further at 24 hours (1.45±0.32 and 1.91±0.46 respectively) (P<0.05). CONCLUSION: GrmRNA expression decreased in LPS induced lung injury in rats. Combined treatment with VIP and GC mitigated lung injury ang inflammation. The mechanism may be related to up-regulation of GR mRNA expression.