Peiminine regulates the biological characteristics of colorectal cancer cells via P13K/Akt/mTOR and oxidative stress pathways

Purpose: To investigate the influence of peiminine on biological characteristics of colorectal cancer cells, and the underlying mechanism.Methods: Two groups of cultured human colorectal cancer HCT-116 cells were used: peiminine and control groups. Peiminine group cells were exposed to the drug at a final concentration of 100 μmol/L. The effect of peiminine on cell proliferation was determined with CCK-8 method, while its effect on apoptosis was determined with flow cytometric method. Cell migration was determined with scratch test. The effect of peiminine on the expressions of proteins associated with the P13K/Akt/mTOR pathway and Wnt/β-catenin pathway in HCT-116 cells was determined with Western blotting assay.Results: Cell proliferation was markedly reduced in the peiminine group, relative to control (p < 0.05). There was higher percentage cell apoptosis in peiminine-treated cells than in control. Moreover, cell migration potential was significantly lower in the peiminine-treated cells. There were significantly downregulated levels of p-P13K, p-Akt and p-mTOR expressions in peiminine group, relative to the corresponding control expressions (p < 0.05). However, there were significantly higher relative expression of Wnt in peiminine group than in control cells, but β-catenin level was reduced, relative to the corresponding control level (p < 0.05).Conclusion: These data indicate that peiminine suppresses the proliferative, apoptotic and migratory potential of colorectal carcinoma HCT-116 cells via regulation of P13K/Akt/mTOR and oxidative stress pathways

Merger-induced star formation in low-metallicity dwarf galaxy NGC 4809/4810

The physical mechanisms driving starbursts in dwarf galaxies are unclear, and the effects of mergers on star formation in these galaxies are still uncertain. We explore how the merger process affects star formation in metal-poor dwarf galaxies by analyzing high-spatial-resolution ($\sim$ 70 pc) integral field spectrograph observations of ionized gas. We use archival data from the Very Large Telescope/Multi Unit Spectroscopic Explorer to map the spatial distribution of strong emission lines (e.g., $\rm H\beta$, $\rm H\alpha$, $\rm [OIII]\lambda5007$, $\rm [NII]\lambda6583$, etc) in the nearby merging star-forming dwarf galaxy system NGC 4809/4810. We identify approximately 112 star-forming knots scattered among the two galaxies, where the gas-phase metallicity distribution is inhomogeneous and mixing with metal-poor and metal-rich ionized gas. Star-forming knots at the interacting region show lower metallicity, the highest star formation rates (SFRs) and SFR to resolved main-sequence-relation (rMSR) ratios. Ionized gas exhibits an obvious northeast-southwest velocity gradient in NGC 4809, while seemingly mixed in NGC 4810. High virial parameters and the stellar mass-size relation of HII regions indicate that these regions are dominated by direct radiation pressure from massive stars/clusters and persistently expanding. We find two different stellar mass surface density-stellar age relations in NGC 4809 and NGC 4810, and the stellar ages of NGC 4810 are systematically younger than in NGC 4809. Our study suggests that the merging stage of two dwarf galaxies can induce starburst activities at the interaction areas, despite the metal-deficient environment. Considering the high specific SFRs and different stellar ages, we propose that the interaction initially triggered star formation in NGC 4809 and then drove star formation in NGC 4810.Comment: 13 pages, 12 figures; accepted for publication in A&

Direct observation of nucleation in the bulk of an opaque sample

Remarkably little is known about the physical phenomena leading to nucleation of new perfect crystals within deformed metals during annealing, in particular how and where volumes with nearly perfect lattices evolve from structures filled with dislocations, and how local variations at the micrometer length scale affect this nucleation process. We present here the first experimental measurements that relate directly nucleation of recrystallization to the local deformation microstructure in the bulk of a sample of cold rolled aluminum, further deformed locally by a hardness indentation. White beam differential aperture X-ray microscopy is used for the measurements, allowing us to map a selected gauge volume in the bulk of the sample in the deformed state, then anneal the sample and map the exact same gauge volume in the annealed state. It is found that nuclei develop at sites of high stored energy and they have crystallographic orientations from those present in the deformed state. Accordingly we suggest that for each nucleus the embryonic volume arises from a structural element contained within the voxels identified with the same orientation. Possible nucleation mechanisms are discussed and the growth potentials of the nuclei are also analyzed and discussed

A single-cell analysis of the molecular lineage of chordate embryogenesis

Progressive unfolding of gene expression cascades underlies diverse embryonic lineage development. Here, we report a single-cell RNA sequencing analysis of the complete and invariant embryonic cell lineage of the tunicate Ciona savignyi from fertilization to the onset of gastrulation. We reconstructed a developmental landscape of 47 cell types over eight cell cycles in the wild-type embryo and identified eight fate transformations upon fibroblast growth factor (FGF) inhibition. For most FGF-dependent asymmetric cell divisions, the bipotent mother cell displays the gene signature of the default daughter fate. In convergent differentiation of the two notochord lineages, we identified additional gene pathways parallel to the master regulator T/Brachyury. Last, we showed that the defined Ciona cell types can be matched to E6.5-E8.5 stage mouse cell types and display conserved expression of limited number of transcription factors. This study provides a high-resolution single-cell dataset to understand chordate early embryogenesis and cell lineage differentiation

The role of school organizational conditions in teacher psychological resilience and stress during COVID-19 pandemic: A moderated mediation model

Educational revisions facilitate the relief of teacher stress by means of enhancing school organizational conditions. However, limited research has explored the effects of school organizational conditions on teacher stress in China. Using a sample of 734 primary and secondary school teachers from 30 provinces or municipalities of China, this study examined the effects of school organizational conditions on teacher stress in China, with a particular focus on the mediating role of psychological resilience and moderating role of perceived COVID-19 crisis strength. The results demonstrated that school organizational conditions were negatively associated with teacher stress. Furthermore, psychological resilience partially mediated the relation between school organizational conditions and teacher stress. In addition, perceived COVID-19 crisis strength significantly moderated the direct and indirect relations between school organizational conditions and teacher stress. The relations between school organizational conditions and teacher stress and between school organizational conditions and psychological resilience were stronger for teachers who perceived low levels of COVID-19 crisis strength. However, the indirect relation between psychological resilience and stress was stronger for teachers who perceived high levels of COVID-19 crisis strength. Implications have been provided accordingly