The Genes Coding for the Conversion of Carbazole to Catechol Are Flanked by IS6100 Elements in Sphingomonas sp. Strain XLDN2-5

BACKGROUND: Carbazole is a recalcitrant compound with a dioxin-like structure and possesses mutagenic and toxic activities. Bacteria respond to a xenobiotic by recruiting exogenous genes to establish a pathway to degrade the xenobiotic, which is necessary for their adaptation and survival. Usually, this process is mediated by mobile genetic elements such as plasmids, transposons, and insertion sequences. FINDINGS: The genes encoding the enzymes responsible for the degradation of carbazole to catechol via anthranilate were cloned, sequenced, and characterized from a carbazole-degrading Sphingomonas sp. strain XLDN2-5. The car gene cluster (carRAaBaBbCAc) and fdr gene were accompanied on both sides by two copies of IS6100 elements, and organized as IS6100::ISSsp1-ORF1-carRAaBaBbCAc-ORF8-IS6100-fdr-IS6100. Carbazole was converted by carbazole 1,9a-dioxygenase (CARDO, CarAaAcFdr), meta-cleavage enzyme (CarBaBb), and hydrolase (CarC) to anthranilate and 2-hydroxypenta-2,4-dienoate. The fdr gene encoded a novel ferredoxin reductase whose absence resulted in lower transformation activity of carbazole by CarAa and CarAc. The ant gene cluster (antRAcAdAbAa) which was involved in the conversion of anthranilate to catechol was also sandwiched between two IS6100 elements as IS6100-antRAcAdAbAa-IS6100. Anthranilate 1,2-dioxygenase (ANTDO) was composed of a reductase (AntAa), a ferredoxin (AntAb), and a two-subunit terminal oxygenase (AntAcAd). Reverse transcription-PCR results suggested that carAaBaBbCAc gene cluster, fdr, and antRAcAdAbAa gene cluster were induced when strain XLDN2-5 was exposed to carbazole. Expression of both CARDO and ANTDO in Escherichia coli required the presence of the natural reductases for full enzymatic activity. CONCLUSIONS/SIGNIFICANCE: We predict that IS6100 might play an important role in the establishment of carbazole-degrading pathway, which endows the host to adapt to novel compounds in the environment. The organization of the car and ant genes in strain XLDN2-5 was unique, which showed strong evolutionary trail of gene recruitment mediated by IS6100 and presented a remarkable example of rearrangements and pathway establishments

The effects of patients initiated aggression on Chinese medical students’ career planning

Abstract Background Patient initiated aggression is common among Chinese health-care workers, reaching over 10,000 incidents annually (Jinyang web. http://6d.dxy.cn/article/55497 . 2013), and the tense doctor-patient relationship generates stress among medical students. Because of the paucity of data (few surveys pay attention to the effects of violence perpetrated by patients on medical students), this study aimed to characterize patient initiated aggression against medical students. Methods In this cross-sectional survey conducted at a medical school in West China in 2015, 157 medical students completed a self-administered questionnaire and the Short Form-36, which assesses quality of life. The associations between patient initiated aggression exposure and medical students’ career planning or quality of life were assessed using a chi-square test. Results Of the 157 medical students, 48 (30.6%) reported having suffered patient initiated aggression at least once during the previous year in the form of mental abuse (20.4%), offensive threat (14.6%), physical violence (8.3%), sexual harassment (verbal: 8.3% or physical: 1.6%), and extreme violence (physical violence leading to surgical treatment or hospitalization) (0.6%). Insufficient communication was the primary reason cited (27.2%). Emotional attack (mental abuse and offensive threat) occurrence differed among age groups (χ2 = 9.786, P = 0.020) and was ubiquitous among those aged >30 years old. Women were more likely than men to suffer physical violence (χ2 = 6.796, P = 0.009). Patient initiated aggression was not significantly associated with medical students’ career planning or quality of life. Conclusions In this study, patient initiated aggression, albeit common, as in the rest of China, did not appear to be associated with medical students’ career planning or quality of life. However, the characteristics described can inform policymaking and the design of programs to minimize patient initiated aggression occurrence

Synthesis, crystal structure and computational chemistry research of a Zinc(II) complex: [Zn(Pt)(Biim)2]

The title metal-organic coordination complex [Zn(pt)(Biim)2] (pt=phthalic acid, benzene-1,2-dicarboxylate, Biim=2,2'-biimidazole) 1 has been obtained by using hydrothermal synthesis and characterized by single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group P21/n with a = 8.5466(15) Å, b = 11.760(2) Å, c = 20.829(4) Å, β = 95.56(2)º, V = 2083.5(6) Å3, Mr =497.78, Dc = 1.587 g/cm3, μ(MoKα) = 1.226 mm−1, F(000) = 1016, Z = 4, the final R = 0.0564 and wR = 0.1851 for 3656 observed reflections (I > 2σ(I)). The elemental analysis, IR, TG and the theoretical calculation were also investigated

Large Collection Satellite Images Color Normalization Algorithm Based on Tone Reference Map

For a large collection of satellite images,because of the differences in season,light,atmospheric conditions and so on,adjacent satellite images may have different color and there will be obviously "seam-line" in mosaic satellite image.In this paper,a method of satellite image color normalization was proposed,it was implemented to correct the color of image automatically based on better color low resolution satellite imagery which covered the mapping area.We selected a large collection and long time interval GF-1 satellite images as experiment data,results show that the mosaic image have a good visual effect,the color transition of two images smoothly,statistical indicators of overlap area obviously improved,all of those verified the validity and reliability of the algorithm

A Novel Method for Constructing Main-Aftershock Sequences and Its Application in the Global Damage Accumulation Effects Analysis of Gravity Dams

The traditional linear elastic and Drucker–Prager (DP) models cannot truly reflect the strong nonlinear characteristics of the concrete and rock foundation of the dam under earthquake. Therefore, for comprehensive evaluation of the cumulative damage of the gravity dam structure caused by aftershock, the dynamic damage of the dam body concrete is analyzed by many scholars through the plastic damage mechanics method, but there is little research on rock material at the dam foundation with the method utilized; thus, the simulation of the whole dynamic damage evolution is worthy of investigation of the dam body and dam foundation. According to the randomness of ground motion, the transcendental probability (P) is introduced to express the statistical characteristics of aftershock intensity, and a new method for constructing main-aftershock sequences of ground motion is proposed in this paper. And then, the law of the damage evolution and energy characteristics of the concrete gravity dam under the combined action of the main shock and aftershock sequences is studied. The results are shown as follows: the smaller aftershocks do not cause further damage to the dam; as the aftershock intensity increases, the energy characteristics of the dam body and foundation have shown different changing rules; when the ratio of peak aftershock acceleration to peak main shock acceleration (∇PGA) approximately equals 0.68, the aftershock will cause larger secondary damage to the dam

Tracking Formation and Decomposition of Abacus-Ball-Shaped Lithium Peroxides in Li–O₂ Cells

Study of formation and decomposition of Li₂O₂ during operations of Li–O₂ cells is essential for understanding the reaction mechanism and finding solutions to improve the cell performance. Using vertically aligned carbon nanotubes (VACNTs) directly grown on stainless steel meshes as the cathodes in the Li–O₂ cells with dimethoxyethane (DME) electrolytes, nucleation, growth, and decomposition processes of the Li₂O₂ in the first cycle are clearly visualized. Through cycles with the controlled discharge and charge capacities, the abacus-ball-shaped Li₂O₂ and the rust-like carbonates simultaneously formed around the VACNTs are further identified. It is indicated that the increasing coverage of carbonates on the cathode surface suppresses the formation of Li₂O₂, which maintains the shape of abacus ball. When the VACNT surfaces are predominantly covered by the carbonates, the cells tend to terminate

Impact of VKORC1, CYP4F2 and NQO1 gene variants on warfarin dose requirement in Han Chinese patients with catheter ablation for atrial fibrillation

Abstract Background The anticoagulation of atrial fibrillation catheter ablation during the perioperative stage does matter and should be treated with discretion. We aimed to assess impact of three important genes participating in vitamin K cycle (i.e. VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566) on the daily stable warfarin dose requirement in Sichuan Han Chinese patients with catheter ablation of atrial fibrillation. Methods A total of 222 atrial fibrillation patients taking stable warfarin therapy after catheter ablation operation were enrolled in this study. The study population included had high (≥2) risk according to the CHA2DS2-VASc risk score. Genotypes of VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566 were analyzed by using the polymerase chain reaction restriction fragment length polymorphism method (PCR-RFLP). Multiple linear regression analysis was applied to depict the impact of VKORC1 rs9923231, CYP4F2 rs2108622 and NQO1 rs1800566 on the daily stable warfarin dose requirement. Results Carriers of VKORC1 rs9923231 AG/GG genotypes required significantly higher warfarin dose (3.03 ± 0.28 mg/day, 7.19 mg/day, respectively) than AA carriers (2.52 ± 0.07 mg/day; P < 0.001). Carriers of CYP4F2 rs2108622 CT/TT genotypes required significantly higher warfarin dose (3.38 ± 0.22 mg/day, 2.79 ± 0.19 mg/day, respectively) than CC carriers (2.41 ± 0.08 mg/day; P < 0.001). However, the warfarin dose for carriers of NQO1 rs1800566 CT/TT genotypes (2.46 ± 0.24 mg/day, 3.01 ± 0.27 mg/day, respectively) was not significantly higher than that for the CC carriers (2.33 ± 0.1 mg/day). The multiple linear regression model including genotypes and demographic characteristics, could explain 20.1% of individual variations in the daily stable warfarin dose in Sichuan Han Chinese. VKORC1 rs9923231 contributed most (15%) to the individual variations in daily stable warfarin dose, while CYP4F2 rs2108622 contributed least (3%). Conclusion NQO1 rs1800566 is not a significant genetic factor of warfarin dose for Han Chinese, whereas VKORC1 rs9923231 and CYP4F2 rs2108622 are significant genetic factors, which could explain 15% and approximately 3% of individual variations in the daily stable warfarin dose respectively

Follistatin Is a Novel Chemoattractant for Migration and Invasion of Placental Trophoblasts of Mice

Follistatin (FST) as a gonadal protein is central to the establishment and maintenance of pregnancy. Trophoblasts&rsquo; migration and invasion into the endometrium are critical events in placental development. This study aimed to elucidate the role of FST in the migration and invasion of placental trophoblasts of mice. We found that FST increased the vitality and proliferation of primary cultured trophoblasts of embryonic day 8.5 (E8.5) mice and promoted wound healing of trophoblasts. Moreover, FST significantly induced migration of trophoblasts in a microfluidic device and increased the number of invasive trophoblasts by Matrigel-coated transwell invasion assay. Being treated with FST, the adhesion of trophoblasts was inhibited, but intracellular calcium flux of trophoblasts was increased. Western blotting results showed that FST had no significant effects on the level of p-Smad3 or the ratio of p-Smad3/Smad3 in trophoblasts. Interestingly, FST elevated the level of p-JNK; the ratio of p-JNK/JNK; and expression of migration-related proteins N-cadherin, vimentin, ezrin and MMP2 in trophoblasts. Additionally, the migration of trophoblasts and expression of N-cadherin, vimentin, and MMP2 in trophoblasts induced by FST were attenuated by JNK inhibitor AS601245. These findings suggest that the elevated FST in pregnancy may act as a chemokine to induce trophoblast migration and invasion through the enhanced JNK signaling to maintain trophoblast function and promote placental development