Development of an inducible transposon system for efficient random mutagenesis in Clostridium acetobutylicum

Clostridium acetobutylicum is an industrially important Gram-positive organism which is capable of producing economically important chemicals in the ABE (Acetone, Butanol and Ethanol) fermentation process. Renewed interests in the ABE process necessitate the availability of additional genetics tools to facilitate the derivation of a greater understanding of the underlying metabolic and regulatory control processes in operation through forward genetic strategies. In this study, a xylose inducible, mariner-based, transposon system was developed and shown to allow high-efficient random mutagenesis in the model strain ATCC 824. Of the thiamphenicol resistant colonies obtained, 91.9% were shown to be due to successful transposition of the catP-based mini-transposon element. Phenotypic screening of 200 transposon clones revealed a sporulation-defective clone with an insertion in spo0A, thereby demonstrating that this inducible transposon system can be used for forward genetic studies in C. acetobutylicum

Influences of feldspars on the storage and permeability conditions in tight oil reservoirs: A case study of Chang-6 group, Ordos Basin

Based on the results from rock thin section observation, casting thin section identification, high-pressure mercury injection, rate-controlled porosimetry, X-ray diffraction, and high resolution field emission CMOS scanning election microscope observation and analysis, influences of feldspar minerals on the storage and permeability conditions in Chang-6 oil layer group in the Yanchang Formation of the Ordos Basin were studied from crystallography and mineralogy perspectives. Due to the differences of crystal structure and chemical composition, the brittleness and solubility of feldspar minerals vary greatly. The results indicate that basic plagioclase such as anorthite tend to split along the cleavage to form new flow channel in formation conditions. Alkaline feldspar rich in potassium such as orthoclase tend to corrode along the cleavage to form secondary porosity. The brittleness and solubility of acid plagioclase, such as albite, are between anorthite and orthoclase. The dominant pore type in Chang-6 oil layer group of Ordos Basin is residual inter-granular pore, the secondary pores generated by corrosion and fracture of feldspar have little contribution to porosity. In the area with higher content of anorthite, the micro-cracks resulted from breaking in cleavage effectively improve the permeability. The contribution of feldspar minerals to permeability is ranked from great to small as anorthite, orthoclase and albite. Key words: Ordos Basin, Chang-6 oil layer group, tight oil, feldspa

VDR Agonist Prevents Diabetic Endothelial Dysfunction through Inhibition of Prolyl Isomerase-1-Mediated Mitochondrial Oxidative Stress and Inflammation

Background and aim. Upregulation of prolyl isomerase-1 (Pin1) protein expression and activity was associated with the pathogenesis of diabetic vasculopathy through induction of endothelial oxidative stress and inflammation. Moreover, VDR agonist protects against high glucose-induced endothelial apoptosis through the inhibition of oxidative stress. We aimed to explore the effects of the VDR agonist on diabetes-associated endothelial dysfunction and the role of Pin1 in this process. Methods. Streptozocin-induced diabetic mice were randomly treated with vehicle, VDR agonist (10 μg/kg/d, i.g., twice a week), or Pin1 inhibitor, Juglone (1 mg/kg/d, i.p., every other day), for eight weeks. In parallel, human umbilical vein endothelial cells (HUVECs) exposed to high-glucose condition were treated with 1,25-dihydroxyvitamin D3 and Juglone or vehicle for 72 hours. Organ chamber experiments were performed to assess endothelium-dependent relaxation to acetylcholine. Circulatory levels of Pin1, SOD, MDA, IL-1β, IL-6, and NO in diabetic mice, Pin1 protein expression and activity, subcellular distribution of p66Shc, and NF-κB p65 in high glucose-cultured HUVECs were determined. Results. Both VDR agonist and Juglone significantly improved diabetes-associated endothelial dysfunction and reduced high glucose-induced endothelial apoptosis. Mechanistically, the circulatory levels of SOD and NO were increased compared with those of vehicle-treated diabetic mice. Additionally, Pin1 protein expression and activity, p66Shc mitochondrial translocation, and NF-κB p65 in high glucose-cultured HUVECs were also inhibited by VDR agonist and Juglone. Knockdown of VDR abolished the inhibitory effects of VDR agonist on high glucose-induced upregulation of Pin1 protein expression and activity. Conclusions. VDR agonist prevents diabetic endothelial dysfunction through inhibition of Pin1-mediated mitochondrial oxidative stress and inflammation

Anti-Diabetic Atherosclerosis by Inhibiting High Glucose-Induced Vascular Smooth Muscle Cell Proliferation via Pin1/BRD4 Pathway

Background and purpose. Vascular smooth muscle cells (VSMC) proliferation and migration is the important pathological process of diabetic atherosclerosis. Bromine domain protein 4 (BRD4) is involved in cell proliferation and inflammatory disease. Pin1 enhances BRD4 stability and its transcriptional activity. This study aimed to explore the possible mechanism of Pin1/BRD4 in diabetic atherosclerosis. Methods. Diabetic Apoe-/- mice induced by streptozotocin were treated with vehicle, the Pin1 inhibitor juglone, or the BRD4 inhibitor JQ1 for 3 weeks. VSMCs were pretreated with juglone, JQ1, or vehicle for 45 min, and then exposed to high glucose for 48 h. Hematoxylin–eosin staining was performed to assess atherosclerotic plaques of the thoracic aorta. Western blotting was used to detect expression levels of Pin1, BRD4, cyclin D1, and matrix metalloproteinase-9 (MMP-9) in the thoracic aorta and VSMCs. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and transwell assay were used to measure proliferation and migration of VSMCs. Results. Juglone and JQ1 significantly improved atherosclerosis of diabetic Apoe-/- mice and reduced high glucose-induced VSMC proliferation and migration. Cyclin D1 and MMP-9 levels in the thoracic aorta were lower in diabetic Apoe-/- mice treated with juglone and JQ1 compared with vehicle-treated diabetic Apoe-/- mice. Additionally, BRD4 protein expression in high glucose-induced VSMCs was inhibited by juglone and JQ1. Upregulation of Pin1 expression by transduction of the Pin1 plasmid vector promoted BRD4 expression induced by high glucose, and stimulated proliferation and migration of VSMCs. Conclusions. Inhibition of Pin1/BRD4 pathway may improve diabetic atherosclerosis by inhibiting proliferation and migration of VSMCs

Depth-of-Field-Extended Plenoptic Camera Based on Tunable Multi-Focus Liquid-Crystal Microlens Array

Plenoptic cameras have received a wide range of research interest because it can record the 4D plenoptic function or radiance including the radiation power and ray direction. One of its important applications is digital refocusing, which can obtain 2D images focused at different depths. To achieve digital refocusing in a wide range, a large depth of field (DOF) is needed, but there are fundamental optical limitations to this. In this paper, we proposed a plenoptic camera with an extended DOF by integrating a main lens, a tunable multi-focus liquid-crystal microlens array (TMF-LCMLA), and a complementary metal oxide semiconductor (CMOS) sensor together. The TMF-LCMLA was fabricated by traditional photolithography and standard microelectronic techniques, and its optical characteristics including interference patterns, focal lengths, and point spread functions (PSFs) were experimentally analyzed. Experiments demonstrated that the proposed plenoptic camera has a wider range of digital refocusing compared to the plenoptic camera based on a conventional liquid-crystal microlens array (LCMLA) with only one corresponding focal length at a certain voltage, which is equivalent to the extension of DOF. In addition, it also has a 2D/3D switchable function, which is not available with conventional plenoptic cameras