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Due to abundant availability of shale gas and biogas, methane has been considered as one of the most potential carbon sources for industrial biotechnology. Methanotrophs carrying the native methane monooxygenase are capable of using methane as a sole energy and carbon source, which provides a novel strategy for reducing greenhouse gas emission and substituting edible substrates used in bioconversion processes. With the rapid development of genetic engineering tools and biosynthesis techniques, various strategies for improving the efficiency of methane bioconversion have been achieved to produce a variety of commodity bio-based products. Herein, we summarize several important aspects related with methane utilization and metabolic engineering of methanotrophs, including the modification of methane oxidation pathways, the construction of efficient cell factories, and biosynthesis of chemicals and fuels. Finally, the prospects and challenges of the future development of methane bioconversion are also discussed.
Subject(s)
Biofuels , Biotechnology , Metabolic Engineering , Methane , Oxidation-ReductionABSTRACT
BACKGROUND: The age of patients with lumbar disc herniation tends to younger, and choosing which surgical method for young patients is a difficult in clinic. . OBJECTIVE: To investigate the curative efficacy and imaging characteristics of the dynamic stabilization using Bioflex System for young patients with single-level lumbar disc herniation. METHODS: Eighty patients diagnosed for single level lumbar disc herniation in Shenzhen Hospital of Chinese Medicine from October 2013 to November 2015 were randomly divided into experimental and control groups (n=40 per group). The patients in the experimental group underwent dynamic stabilization using Bioflex System, and the controls received percutaneous transthoracic discectomy. The Visual Analogue Scale and Japanese Orthopedic Association scores and Oswestry Disability Index were used to evaluate the clinical efficacy. The ventral and dorsal intervertebral disc height, distance between spinous processes, and the maximum height between intervertebral foramens were measured through digital radiography, CT and MRI examinations at baseline, 3, 6, and 12 months of follow-up. The operation time, intraoperative blood loss and complications were compared between groups. RESULTS AND CONCLUSION: (1) At 12 months postoperatively, the restoration of the ventral and dorsal intervertebral disc height, distance between spinous processes, and the maximum height between intervertebral foramens in the experimental group were significantly superior to those in the control group (P < 0.05). (2) The Visual Analogue Scale and Japanese Orthopedic Association scores and Oswestry Disability Index scores were significantly improved in both groups (P < 0.05); all above scores did not differ significantly between two groups at 3 and 6 months postoperatively (P >0.05); and all above scores in the experimental group were significantly superior to those in the control group at 12 months postoperatively (P < 0.05). (3) The operation time and intraoperative blood loss in the experimental group were significantly lower than those in the control group (P < 0.05). (4) There were no significant differences in the incidence of complications between two groups (P > 0.05). (5) These results show that although percutaneous transthoracic discectomy has advantages on the operation time and intraoperative blood loss; the two surgical methods show no significant differences in the early curative efficacy and complications. Besides, in terms of long-term efficacy, Bioflex System can significantly alleviate pain, restore intervertebral height, and prevent degeneration of the intervertebral disc and adjacent vertebrae.
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BACKGROUND: Yaotu Granules have been proved to protect human nucleus pulposus cells and delay their degeneration. Notably, Yaotu Granules for lumbar disc herniation has achieved good clinical results.OBJECTIVE: To investigate the effect of the herbal compound formula Yaotu Granules on the Fas/FasL expression in a rabbit model of lumbar disc degeneration, and further elucidate the underling mechanism of preventing and treating lumbar disc degeneration.METHODS: Twenty New Zealand white rabbits were enrolled and the models of lumbar disc degeneration were established by minimally invasive puncture and rotation cutting, followed by randomized into normal saline, low-, middle-,and high-dose groups (n=5 per group). 10 mL of normal saline, 10, 20, and 40 mL of water decoction of Yaotu Granules were administered intragastrically into the normal saline, low-, middle-, and high-dose drug groups for 21 days, twice daily, respectively. Subsequently, the expression level of Fas/FasL in the rabbit nucleus pulposus cells in each group was detected.RESULTS AND CONCLUSION: The signal intensity of the rabbit lumbar disc on MRI was decreased, and ruptured annulus and posterior herniated disc were visible at 12 weeks after modeling. Masson staining showed that the nucleus pulposus cells arranged in disorder, and even ruptured. Additionally, safranin O staining found that the number of nucleus pulposus cells was decreased obviously. The order of the relative expression levels of Fas and FasL mRNA in the nucleus pulposus cells was as follows: normal saline group > low-dose drug group > middle-dose drug group > high-dose drug group (P < 0.05). These results suggest that Yaotu Granules delay the rabbit lumbar disc degeneration by downregulating the expression level of Fas/FasL.
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Prostaglandin (PG) E2 is an active substance in pathological and physiological mechanisms, such as inflammation and pain. The in vitro high-throughput assay for screening the inhibitors of reducing PEG2 production is a useful method for finding out antiphlogistic and analgesic candidates. The assay was based on LPS-induced PGE2 production model using a homogeneous time-resolved fluorescence(HTRF) PGE2 testing kit combined with liquid handling automation and detection instruments. The critical steps, including the cell density optimization and IC50 values determination of a positive compound, were taken to verify the stability and sensibility of the assay. Low intra-plate, inter-plate and day-to-day variability were observed in this 384-well, high-throughput format assay. Totally 5 121 samples were selected from the company's traditional Chinese medicine(TCM) material base library and used to screen PGE2 inhibitors. In this model, the cell plating density was 2 000 cells for each well; the average IC₅₀ value for positive compounds was (7.3±0.1) μmol; the Z' factor for test plates was more than 0.5 and averaged at 0.7. Among the 5 121 samples, 228 components exhibited a PGE2 production prohibition rate of more than 50%, and 23 components exhibited more than 80%. This model reached the expected standards in data stability and accuracy, indicating the reliability and authenticity of the screening results. The automated screening system was introduced to make the model fast and efficient, with a average daily screening amount exceeding 14 000 data points and provide a new model for discovering new anti-inflammatory and analgesic drug and quickly screening effective constituents of TCM in the early stage.
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To discuss the synergistic mechanism of compatible use of two medicinal herbs,Panax notoginseng and Bletilla striata, an HPLC was established to determine two ginseng saponins (20S)-ginseng saponin Rg₃ and ginseng saponin Rh₄ contained in single decoction of Panax notoginseng as well as in compound decoction of Panax notoginseng and Bletillastriata in different compatibility ratio (1∶0.5, 1∶1, 1∶2), followed by analyzing the impact of amount of notoginsenosides after compatibility. As a result, compared with the single decoction of Panax notoginseng, the contents of ginseng saponin Rg₃ and ginseng saponin Rh₄ in the compound decoction of Panax notoginseng and Bletillastriata were on the rise as the increasement of the amount of Bletillastriata. The contents of the notoginsengsaponin R₁, ginseng saponin Rg₁ and ginseng saponin Rb₁ of Panax notoginseng single decoction were significantly decreased after compatibility. Therefore, after compatibility, it was more easy to produce (20S)-ginseng saponin Rg₃ and ginseng saponin Rh₄.This study can extend to a method of preparation of (20S)-ginseng saponin Rg₃ and ginseng saponin Rh₄. Furthermore, after compatibility, two ginseng saponins which had lipase inhibitory effect were both increased significantly, indicating that the compatibility of these two herb medicines may have effect on losing weight.
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<p><b>BACKGROUND</b>Treatments to regenerate different tissue involving the transplantation of bone marrow derived mesenchymal precursor cells are anticipated. Using an alternative methods, in vitro organotypic slice culture method, would be useful to transplant cells and assessing the effects. This study was to determine the possibility of differentiating human bone marrow precursor cells into cells of the neuronal lineage by transplanting into canine spinal cord organotypic slice cultures.</p><p><b>METHODS</b>Bone marrow aspirates were obtained from posterior superior iliac spine (PSIS) of patients that had undergone spinal fusion due to a degenerative spinal disorder. For cell imaging, mesenchymal precursor cells (MPCs) were pre-stained with PKH-26 just before transplantation to canine spinal cord slices. Canine spinal cord tissues were obtained from three adult beagle dogs. Spinal cords were cut into transverse slices of 1 mm using tissue chopper. Two slices were transferred into 6-well plate containing 3 ml DMEM with antibiotics. Prepared MPCs (1×10(4)) were transplanted into spinal cord slices. On days 0, 3, 7, 14, MPCs were observed for morphological changes and expression of neuronal markers through immunofluorescence and reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>The morphological study showed: spherical cells in the control and experiment groups on day 0; and on day 3, cells in the control group had one or two thick, short processes and ones in the experiment group had three or four thin, long processes. On day 7, these variously-sized processes contacted each other in the experiment group, but showed typical spindle-shaped cells in the control group. Immunofluorescence showed that PKH-26(+) MPCs stained positive for NeuN(+) and GFAP(+) in experimental group only. Also RT-PCR showed weak expression of β-tubulin III and GFAP.</p><p><b>CONCLUSIONS</b>Human bone marrow mesenchymal precursor cells (hMPCs) have the potential to differentiate into the neuronal like cells in this canine spinal cord organotypic slice culture model. Furthermore, these findings suggested the possibility that these cells can be utilized to treat patients with spinal cord injuries.</p>
Subject(s)
Animals , Dogs , Humans , Bone Marrow Cells , Cell Biology , Cell Differentiation , Physiology , Cells, Cultured , Mesenchymal Stem Cells , Cell Biology , Spinal Cord , Cell BiologyABSTRACT
Objective To establish a normal lumbar spine 3-dimensional(3D) finite element model(FEM) and discuss the biomechanics of the lumbar motions. Methods A geometrical model was constructed on the basis of a healthy adult male's lumbar CT image.The lumbar spine FEM was established by finite element analysis software.After setting the boundary and loading the burden,the lumbar spine's range of motion and stress distribution in different institutions such as anterior flexion,posterior extension,left or right bending and axial rotating were recorded. Results The lumbar spine FEM included 114 953 tetrahedron units.The results of the FEM matched the results of the in vitro experiment of biomechanics. Conclusion The lumbar spine FEM can imitate the motions of the lumbar spine.