Investigation of Structures, Stabilities, and Electronic and Magnetic Properties of Niobium Carbon Clusters Nb7Cn (n = 1-7)

The geometrical structures, relative stabilities, and electronic and magnetic properties of niobium carbon clusters, Nb7Cn (n = 1-7), are investigated in this study. Density functional theory (DFT) calculations, coupled with the Saunders Kick global search, are conducted to explore the structural properties of Nb7Cn (n = 1-7). The results regarding the average binding energy, second-order difference energy, dissociation energy, HOMO-LUMO gap, and chemical hardness highlight the robust stability of Nb7C3. Analysis of the density of states suggests that the molecular orbitals of Nb7Cn primarily consist of orbitals from the transition metal Nb, with minimal involvement of C atoms. Spin density and natural population analysis reveal that the total magnetic moment of Nb7Cn predominantly resides on the Nb atoms. The contribution of Nb atoms to the total magnetic moment stems mainly from the 4d orbital, followed by the 5p, 5s, and 6s orbitals.

Knockout of a PLD gene in Schizochytrium limacinum SR21 enhances docosahexaenoic acid accumulation by modulation of the phospholipid profile

BACKGROUND

The hydrolysis and transphosphatidylation of phospholipase D (PLD) play important roles in the interconversion of phospholipids (PLs), which has been shown to profoundly impact lipid metabolism in plants. In this study, the effect of the PLD1 gene of Schizochytrium limacinum SR21 (S. limacinum SR21) on lipid metabolism was investigated.

RESULTS

PLD1 knockout had little impact on cell growth and lipid production, but it significantly improved the percentage of polyunsaturated fatty acids in lipids, of which docosahexaenoic acid (DHA) content increased by 13.3% compared to the wild-type strain. Phospholipomics and real-time quantitative PCR analysis revealed the knockout of PLD1 reduced the interexchange and increased de novo synthesis of PLs, which altered the composition of PLs, accompanied by a final decrease in phosphatidylcholine (PC) and an increase in phosphatidylinositol, lysophosphatidylcholine, and phosphatidic acid levels. PLD1 knockout also increased DHA content in triglycerides (TAGs) and decreased it in PLs.

CONCLUSIONS

These results indicate that PLD1 mainly performs the transphosphatidylation activity in S. limacinum SR21, and its knockout promotes the migration of DHA from PLs to TAGs, which is conducive to DHA accumulation and storage in TAGs via an acyl CoA-independent pathway. This study provides a novel approach for identifying the mechanism of DHA accumulation and metabolic regulation strategies for DHA production in S. limacinum SR21.

Neuroprotective effects of idebenone on hydrogen peroxide-induced oxidative damage in retinal ganglion cells-5

PURPOSE

To investigate the neuroprotective effect of idebenone against hydrogen peroxide (H2O2)-induced oxidative damage in retinal ganglion cells-5 (RGC-5 cells).

METHODS

RGC-5 cells were pre-treated with various idebenone concentrations (5, 10, and 20 µM) for 12 h and were then subjected to 300 µM H2O2 for a further 12 h. Apoptosis in RGC-5 was measured by flow cytometry. The changes of mitochondrial membrane potential (MMP) were detected by JC-1 staining. Autophagy in RGC-5 cells was observed by transmission electron microscopy. Western blots were used to measure the expression of autophagy-related protein light chain 3 (LC3), Beclin-1, and the release of Cytochrome c (Cyt-c).

RESULTS

Flow cytometry showed that the apoptosis rates in the normal control group, H2O2 group, and idebenone groups were 6.48 ± 0.55%, 27.3 ± 0.51%, 22.8 ± 0.52%, 15.45 ± 0.81%, and 12.59 ± 0.58%, respectively (F = 559.7, P < 0.0001). After incubation with H2O2, the number of autophagosomes increased significantly, whereas it was decreased in the idebenone groups. After incubation of RGC-5 cells with H2O2, MMP levels were significantly decreased, while idebenone could prevent the decrease in MMP levels. Compared with that in the normal control group, LC3 II/I, the expression levels of Beclin-1 and Cyt-c were increased significantly in the H2O2 group (P < 0.05). Compared with that in the H2O2 group, LC3 II/I, the expression of Beclin-1 and Cyt-c was significantly decreased in idebenone groups (P < 0.05).

CONCLUSIONS

Idebenone protects RGC-5 cells against H2O2-induced oxidative damage by reducing mitochondrial damage and autophagic activity.

To identify biomarkers associated with the transfer of diabetes combined with cancer in human genes using bioinformatics analysis

Currently, the incidence of diabetes mellitus is increasing rapidly, particularly in China, and its pathogenesis is still unclear. The goal of this study was to find meaningful biomarkers of metastasis in patients with diabetes and cancer using bioinformatic analysis in order to predict gene expression and prognostic importance for survival. We used the Differentially Expressed Gene, Database for Annotation Visualization and Integrated Discovery, and Gene Set Enrichment Analyses databases, as well as several bioinformatics tools, to explore the key genes in diabetes. Based on the above database, we ended up with 10 hub genes (FOS, ATF3, JUN, EGR1, FOSB, JUNB, BTG2, EGR2, ZFP36, and NR4A2). A discussion of the 10 critical genes, with extensive literature mentioned to validate the association between the 10 key genes and patients with diabetes and cancer, to demonstrate the importance of gene expression and survival prognosis. This study identifies several biomarkers associated with diabetes and cancer development and metastasis that may provide novel therapeutic targets for diabetes combined with cancer patients.

Ion fluxes Involved in the Adaptation of the Estuarine Diatom Coscinodiscus centralis Ehrenberg to Salinity Stress

Although estuarine diatoms have a wide range of salt tolerance, they are often severely stressed by elevated salt concentrations. It remains poorly understood how estuarine diatoms maintain ionic homeostasis under high-salinity conditions. Using a scanning ion-selective electrode technique, this study determined the fluxes of H+, Na+, and K+ involved in the acclimatization of the estuarine diatom Coscinodiscus centralis Ehrenberg after an elevation in salinity from 15 psu to 35 psu. The C. centralis cells exhibited marked H+ effluxes after a transient treatment (TT, 30 min) and short-term treatment (ST, 24 h). However, a drastic shift of H+ efflux toward an influx was induced in the long-term treatment (LT, 10 days). The Na+ flux under TT, ST, and LT salinity conditions was found to accelerate the Na+ efflux. More pronounced effects were observed under the ST and LT salinity conditions compared to the TT salinity condition. The K+ influx showed a significant increase under the LT salinity condition. However, the salinity-induced Na+/H+ exchange in the estuarine diatom was inhibited by amiloride and sodium orthovanadate. These results indicate that the Na+ extrusion in salt-stressed cells is mainly the result of an active Na+/H+ antiport across the plasma membrane. The pattern of ion fluxes under the TT and ST salinity conditions were different from those under the LT salinity conditions, suggesting an incomplete regulation of the acclimation process in the estuarine diatom under short-term salinity stress.

The Fate of Heavy Metals and Risk Assessment of Heavy Metal in Pyrolysis Coupling with Acid Washing Treatment for Sewage Sludge

Pyrolysis is an emerging and effective means for sludge disposal. Biochar derived from sludge has broad application prospects, however, is limited by heavy metals. In this study, the fate of heavy metals (HMs) in pyrolysis coupling with acid washing treatment for sewage sludge was comprehensively investigated for the first time. Most of the HMs redistributed in the pyrolyzed residues (biochar) after pyrolysis, and the enrichment order of the HMs was: Zn > Cu > Ni > Cr. Compared with various washing agents, phosphoric acid presented a superior washing effect on most heavy metals (Cu, Zn, and Cr) in biochars derived at low pyrolysis temperature and Ni in biochars derived at high pyrolysis temperature. The optimal washing conditions for heavy metals (including Cu, Zn, Cr, and Ni) removal by H₃PO₄ were obtained by batch washing experiments and the response surface methodology (RSM). The total maximum HM removal efficiency was 95.05% under the optimal washing specifications by H₃PO₄ (acid concentration of 2.47 mol/L, L/S of 9.85 mL/g, and a washing temperature of 71.18 °C). Kinetic results indicated that the washing process of heavy metals in sludge and biochars was controlled by a mixture of diffusion and surface chemical reactions. After phosphoric acid washing, the leaching concentrations of HMs in the solid residue were further reduced compared with that of biochar, which were below the USEPA limit value (5 mg/L). The solid residue after pyrolysis coupling with acid washing resulted in a low environmental risk for resource utilization (the values of the potential ecological risk index were lower than 20). This work provides an environmentally friendly alternative of pyrolysis coupling with acid washing treatment for sewage sludge from the viewpoint of the utilization of solid waste.