Suppression of Grb2 expression improved hepatic steatosis, oxidative stress, and apoptosis induced by palmitic acid in vitro partly through insulin signaling alteration

In this study, we aimed to study the role of growth factor receptor-bound protein 2 (Grb2) in palmitic acid-induced steatosis and other “fatty liver” symptoms in vitro. HepG2 cells, with or without stably suppressed Grb2 expression, were incubated with palmitic acid for 24 h to induce typical clinical “fatty liver” features, including steatosis, impaired glucose metabolism, oxidative stress, and apoptosis. MTT and Oil Red O assays were applied to test cell viability and fat deposition, respectively. Glucose uptake assay was used to evaluate the glucose utilization of cells. Quantitative polymerase chain reaction and Western blot were used to measure expressional changes of key markers of insulin signaling, lipid/glucose metabolism, oxidative stress, and apoptosis. After 24-h palmitic acid induction, increased fat accumulation, reduced glucose uptake, impaired insulin signaling, enhanced oxidative stress, and increased apoptosis were observed in HepG2 cells. Suppression of Grb2 in HepG2 significantly reduced fat accumulation, improved glucose metabolism, ameliorated oxidative stress, and restored the activity of insulin receptor substrate-1/Akt and MEK/ERK pathways. In addition, Grb2 deficiency attenuated hepatic apoptosis shown by reduced activation of caspase-3 and fluorescent staining. Modulation of Bcl-2 and Bak1 also contributed to reduced apoptosis. In conclusion, suppression of Grb2 expression in HepG2 cells improved hepatic steatosis, glucose metabolism, oxidative stress, and apoptosis induced by palmitic acid incubation partly though modulating the insulin signaling pathway.     

3-Pyrroline containing arylacetamides: a novel series of remarkably selective kappa-agonists

A series of 2-(substituted phenyl)-N-methyl-N-[(1S)-1-(substituted alkyl)-2-(1-(3-pyrrolinyl))ethyl]acetamides were synthesized and evaluated as highly selective kappa-agonists with K(i) values in low nanomolar range. 3-Pyrroline incorporated into the basic amino functionality in combination with 2-(methylthio)ethyl substituent on the carbon adjacent to the amide nitrogen remarkably enhanced the kappa-selectivity. 3,4-Dichlorophenyl derivative 1e was found the most potent and selective analgesic in this series with ED(50) value of 0.023 mg/kg.     

Synthesis,luminescence, and excited-state absorption properties of disubstituted perylene diimide derivatives modified at bay region

Three A–π–A or D–π–D perylene diimide ( PDI ) derivatives with varied groups on π-conjugate were synthesized and characterized. The photophysical properties of these compounds were systematically studied by spectral experiments and density functional theory calculations. All compounds displayed intense absorption bands at 300–800 nm wavelengths. However, diverse groups on the π-conjugate influenced the UV–vis absorption. Electron-withdrawing groups on PDI-2 caused a slight red shift at the 350–400 nm wavelength and a blue shift after 400 nm wavelength. At the same time, the electron-donating substituents on PDI-3 caused an obvious red shift of this band. These PDI derivatives exhibited emission in solution at room temperature (λ_em = 500–850 nm). The quantum yield of PDI-3 decreased, while the electron-donating substituents were introduced to the π-conjugated motifs. However, the quantum yield of PDI-2 increased when electron-withdrawing substituents were introduced to the π-conjugated motifs. In addition, PDI-1 and PDI-2 exhibited broad triplet transient absorption in the visible region. These photophysical properties could help us to understand the relationship between structure and photophysical properties of perylene diimide derivatives and exploit more original perylene diimide-based optical functional materials.     

Alterations and Mechanism of Gut Microbiota in Graves’ Disease and Hashimoto’s Thyroiditis

To explore the role of gut microbiota in Graves’ disease (GD) and Hashimoto’s thyroiditis (HT). Seventy fecal samples were collected, including 27 patients with GD, 27 with HT, and 16 samples from healthy volunteers. Chemiluminescence was used to detect thyroid function and autoantibodies (FT3, FT4, TSH, TRAb, TGAb, and TPOAb); thyroid ultrasound and 16S sequencing were used to analyze the bacteria in fecal samples; KEGG (Kyoto Encyclopedia of Genes and Genomes) and COG (Clusters of Orthologous Groups) were used to analyze the functional prediction and pathogenesis. The overall structure of gut microbiota in the GD and HT groups was significantly different from the healthy control group. Proteobacteria and Actinobacteria contents were the highest in the HT group. Compared to the control group, the GD and HT groups had a higher abundance of Erysipelotrichia, Cyanobacteria, and Ruminococcus_2 and lower levels of Bacillaceae and Megamonas. Further analysis of KEGG found that the “ABC transporter” metabolic pathway was highly correlated with the occurrence of GD and HT. COG analysis showed that the GD and HT groups were enriched in carbohydrate transport and metabolism compared to the healthy control group but not in amino acid transport and metabolism. Our data suggested that Bacillus, Blautia, and Ornithinimicrobium could be used as potential markers to distinguish GD and HT from the healthy population and that “ABC transporter” metabolic pathway may be involved in the pathogenesis of GD and HT.     

Biochemical characterization and substrate profiling of a new NADH-dependent enoate reductase from Lactobacillus casei

Carbon-carbon double bond of α,β-unsaturated carbonyl compounds can be reduced by enoate reductase (ER), which is an important reaction in fine chemical synthesis. A putative enoate reductase gene from Lactobacillus casei str. Zhang was cloned into pET-21a+ and expressed in Escherichia coli BL21 (DE3) host cells. The encoded enzyme (LacER) was purified by ammonium sulfate precipitation and treatment in an acidic buffer. This enzyme was identified as a NADH-dependent enoate reductase, which had a K(m) of 0.034 ± 0.006 mM and k(cat) of (3.2 ± 0.2) × 103 s?1 toward NADH using 2-cyclohexen-1-one as the substrate. Its K(m) and k(cat) toward substrate 2-cyclohexen-1-one were 1.94 ± 0.04 mM and (8.4 ± 0.2) × 103 s?1, respectively. The enzyme showed a maximum activity at pH 8.0-9.0. The optimum temperature of the enzyme was 50-55°C, and LacER was relatively stable below 60 °C. The enzyme was active toward aliphatic alkenyl aldehyde, ketones and some cyclic anhydrides. Substituted groups of cyclic α,β-unsaturated ketones and its ring size have positive or negative effects on activity. (R)-(-)-Carvone was reduced to (2R,5R)-dihydrocarvone with 99% conversion and 98% (diasteromeric excess: de) stereoselectivity, indicating a high synthetic potential of LacER in asymmetric synthesis.     

六种鱼腥藻在大量培养中的生产率和适应性与营养成分比较

连续两年对鱼腥藻的六个品系进行了大量培养比较研究,在长江中下游气候条件下,HB1042和HB1105具有稳定的生产性能,5月下旬至九月中旬123d内,平均有效生长分别为114和100d;其次是HB1058,HB686和HB1017,平均有效生长天分别为73,58和71d;HB13适应性较差。生物量生产率在5月下旬、6月中旬至9月中旬较高,除HB13外,平均都在10g干重/m~2/d以上或接近10g/m~2/d。在不同的季节它们表现出了各自的最高生物量生产率。据此,提出了逐月逐旬采取藻种搭配生产,以获得最高生物量生产率的配合关系。营养成分分析表明它们的蛋白质含量在40％左右;氨基酸组成合理,除某些种类的含硫氨基酸略低外,都符合FAO/WHO的标准。     

RAGE mediates amyloid-beta peptide transport across the blood-brain barrier and accumulation in brain

Amyloid-beta peptide (Abeta) interacts with the vasculature to influence Abeta levels in the brain and cerebral blood flow, providing a means of amplifying the Abeta-induced cellular stress underlying neuronal dysfunction and dementia. Systemic Abeta infusion and studies in genetically manipulated mice show that Abeta interaction with receptor for advanced glycation end products (RAGE)-bearing cells in the vessel wall results in transport of Abeta across the blood-brain barrier (BBB) and expression of proinflammatory cytokines and endothelin-1 (ET-1), the latter mediating Abeta-induced vasoconstriction. Inhibition of RAGE-ligand interaction suppresses accumulation of Abeta in brain parenchyma in a mouse transgenic model. These findings suggest that vascular RAGE is a target for inhibiting pathogenic consequences of Abeta-vascular interactions, including development of cerebral amyloidosis.     

Temporal dynamics of soil bacterial network regulate soil resistomes

Soil bacteria are diverse and form complicated ecological networks through various microbial interactions, which play important roles in soil multi-functionality. However, the seasonal effects on the bacterial network, especially the relationship between bacterial network topological features and soil resistomes remains underexplored, which impedes our ability to unveil the mechanisms of the temporal-dynamics of antibiotic resistance genes (ARGs). Here, a field investigation was conducted across four seasons at the watershed scale. We observed significant seasonal variation in bacterial networks, with lower complexity and stability in autumn, and a wider bacterial community niche in summer. Similar to bacterial communities, the co-occurrence networks among ARGs also shift with seasonal change, particularly with respect to the topological features of the node degree, which on average was higher in summer than in the other seasons. Furthermore, the nodes with higher betweenness, stress, degree, and closeness centrality in the bacterial network showed strong relationships with the 10 major classes of ARGs. These findings highlighted the changes in the topological properties of bacterial networks that could further alter antibiotic resistance in soil. Together, our results reveal the temporal dynamics of bacterial ecological networks at the watershed scale, and provide new insights into antibiotic resistance management under environmental changes.