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A protocol for regeneration of Gentiana straminea Maxim recently established in our laboratory, somatic embryogenesis was obtained from its leaf derived calli. The gentiopicroside contents of embryogenic calli, globular-, heart-, torpedo-, and cotyledon-shaped embryoids as well as regenerated plantlets were determined by high-performance liquid chromatography. Gentiopicroside was detectable in all materials tested. Embryogenic calli showed the lowest gentiopicroside content. The changes of gentiopicroside contents were not significant (P<0.05) with the development of somatic embryos. The highest gentiopicroside content (30.7 mg g⁻¹ dry weight) was achieved in regenerated plantlets. The contents of gentiopicroside were not significant (P<0.05) differences between control plants and embryogenic calli, different stages of somatic embryos and regenerated plantlets. This protocol could be employed for producing gentiopicroside or other medicinal compounds.
To solve the dynamic response problems of magnetic coupling in the horizontal axis wave energy device, this has researched the dynamic characteristicsof magnetic coupling. The fitting formula about torque and angle of the magnetic coupling is obtained through experiments. The mathematical models of the magnetic coupling torque transmission are established. The steady state error of the magnetic coupling and the transfer function of the output angle are obtained. The analytical solution of the step response of the output angle in time domain is derived. The influence of the torsional rigidity, the damping coefficient and the driven rotor’s rotational inertia on dynamic characteristics of the magnetic coupling isanalyzed. According to the analysis results, the design rules of magnetic coupling are proposed
Erythropoietin (EPO) has a beneficial effect on hepatic cell proliferation during liver regeneration. However, the underlying mechanism has not yet been elucidated. To uncover the proliferation response of EPO in rat liver regeneration after partial hepatectomy (PH) at the cellular level, hepatocytes (HCs) were isolated using Percoll density gradient centrifugation. The genes of the EPO-mediated signaling pathway and the target genes of the transcription factor (TF) in the pathway were identified in a pathway and TF database search. Their expression profiles were then detected using Rat Genome 230 2.0 Microarray. The results indicated that the EPO-mediated signaling pathway is involved in 19 paths and that 124 genes participate, of which 32 showed significant changes and could be identified as liver regeneration-related genes. In addition, 443 targets regulated by the TFs of the pathway and 60 genes associated with cell proliferation were contained in the array. Subsequently, the synergetic effect of these genes in liver regeneration was analyzed using the E(t) mathematical model based on their expression profiles. The results demonstrated that the E(t) values of paths 3, 8, 12 and 14–17 were significantly strengthened in the progressing phase of liver regeneration through the RAS/MEK/ERK or PI3K/AκT pathways. The synergetic effect of the target genes, in parallel with target-related cell proliferation, was also enhanced 12–72 h after PH, suggesting a potential positive effect of EPO on HC proliferation during rat liver regeneration. These data imply that the EPO receptor may allow EPO to promote HC proliferation through paths 3, 8, 12 and 14–17, mediating the RAS/MEK/ERK and PI3K/AκT pathways in rat liver regeneration after PH.
A river ecosystem is a treasure that is home to a wide variety of wetland species. The construction of bridges might have a deep impact on diversity of such an ecosystem. The ecological consequence of bridge abutments was studied by monitoring the benthic macroinvertebrate community at six main bridges on the Tuhai and Majia rivers in eastern China. We collected samples of macroinvertebrates from upstream to downstream during the summer hight-water period, and we monitored water quality at each site. The macroinvertebrate community of under-bridge sites was signifi cantly correlated with that of reference sites in abundance, biomass, and richness. The benthic macroinvertebrate communities were not significantly different between under-bridge sites and reference sites in terms of abundance and biomass, while they were significantly different in terms of richness and the Shannon-Wiener index. This pattern outlined a major impact of bridge abutments on benthic macroinvertebrate communities for the first time, indicating the importance of habitat restoration after river construction was finished. Suitable measures should be taken to minimize the impact of bridge abutments.
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