丁酸梭菌抑制Cdk2表达经Wnt/βcatenin 信号通路调控结直肠癌细胞迁移

目的研究丁酸梭菌(Clostridium butyricum,C. butyricum)与细胞周期蛋白激酶2(Cdk2)对结直肠癌细胞迁移的作用,探讨其作用机制。方法以结直肠癌细胞DLD1作为研究载体,运用蛋白印迹法(Western blot)、MTT、定量聚合酶链反应(qPCR)、Transwell和划痕实验等研究C. butyricum和Cdk2对结直肠癌形成的影响。结果Western blot和qPCR结果显示,癌组织Cdk2阳性表达率明显高于癌旁组织(t=8.271,P<0.01)。qPCR结果表明C. butyricum在结直肠癌患者粪便中的丰度明显低于正常人群(t=6.903,P<0.05)。MTT、Transwell和划痕实验表明,C. butyricum培养上清作用的结直肠癌细胞生长速度明显低于对照组(MTT:96 h t=4.356,P<0.05; 120 h t=6.025,P<0.05。Transwell:C. butyricum t=3.794,P<0.05; Cdk2 knockdown t=5.086,P<0.01;丁酸梭菌+Cdk2 knockdown t=4.815,P<0.01。划痕:24 h t=4.356,P<0.01; 48 h t=6.025,P<0.01),且C. butyricum通过Cdk2抑制了结直肠癌细胞增殖与迁移能力。Western blot结果显示C. butyricum抑制Cdk2的表达,且与Cdk2协同作用调控Wnt/βcatenin信号通路。结论C. butyricum通过抑制Cdk2经Wnt/βcatenin信号通路调控结直肠癌细胞的增殖和迁移。     

Heterogeneous interactome between Litopenaeus vannamei plasma proteins and Vibrio parahaemolyticus outer membrane proteins

A great loss has been suffered by microbial infectious diseases under intensive shrimp farming in recent years. In this background, the understanding of shrimp innate immunity becomes an importantly scientific issue, but little is known about the heterogeneous protein–protein interaction between pathogenic cells and hosts, which is a key step for the invading microbes to infect internet organs through bloodstream. In the present study, bacterial outer membrane (OM) protein array and pull-down approaches are used to isolate both Vibrio parahaemolyticus OM proteins that bind to shrimp serum proteins and the shrimp serum proteins that interact with bacterial cells, respectively. Three interacting shrimp serum proteins, hemocyanin, β-1,3-glucan binding protein and LV_HP_RA36F08r and thirty interacting OM proteins were determined. They form 63 heterogeneous protein–protein interactions. Nine out of the 30 OM proteins were randomly demonstrated to be up-regulated or down-regulated when bacterial cells were cultured with shrimp sera, indicating the biological significance of the network. The interesting findings uncover the complexity of struggle between host immunity and bacterial infection. Compared with our previous report on heterogeneous interactome between fish grill and bacterial OM proteins, the present study further extends the investigation from lower vertebrates to invertebrates and develops a bacterial OM protein array to identify the OM proteins bound with shrimp serum proteins, which elevates the frequencies of the bound OM proteins. Our results highlight the way to determine and understand the heterogeneous interaction between hosts and microbes.     

竹叶菜的组织培养研究

竹叶菜为百合科鹿药属一种多年生草本植物,因做菜口感好,且营养丰富、药用价值高而成为深受人们喜爱的一种野生蔬菜.有关竹叶菜及其同属的组织培养研究均未见报道.本文以竹叶菜的顶芽为外植体,通过器官发生途径,初步探索了竹叶菜的组织培养技术,结果表明:芽诱导的合适培养基为:MS +6-BA 1.5 +NAA 0.05+0.6％琼脂+3％蔗糖;芽继代培养的合适培养基为:MS+6-BA 1.2 +NAA 0.05 +0.6％琼脂+3％蔗糖;无菌小苗生根的合适培养基为:MS+ IAA 1.5+ NAA 0.2+ 0.6％琼脂+3％蔗糖.为竹叶菜今后较大规模地栽培或生产提供种苗及技术贮备,为实现竹叶菜资源的可持续性开发利用奠定了基础.     

Effect of Arborvitae Seed on Cognitive Function and α7nAChR Protein Expression of Hippocampus in Model Rats with Alzheimer’s Disease

The aim was to investigate the effect of the arborvitae seed on cognitive function and α7-nicotinic acetylcholine receptor (α7nAChR) protein expression of the hippocampus in model rats with Alzheimer’s disease (AD). Thirty-six adult Wistar rats were randomly divided into the control, test, and drug groups. A dose of Aβ_1–40 was injected into the rats’ hippocampus in the test and drug groups and the control rats were injected with the same amount of normal saline. After the model was successful, the rats in the control and test groups were gavaged with sodium carboxymethyl cellulose (500 mg/kg) and the rats in the drug group were gavaged with arborvitae seed powder (500 mg/kg) for 15 days. The Morris water maze test was used for cognitive function. The effect of arborvitae seed on α7nAChR protein immunoreactivity on the hippocampus neurons was studied by the immunohistochemistry method. Behavioral tests showed that the mean escape latencies and search time of the test group were obviously longer than the control and drug groups. The percentage of the search distance of the test group was shorter than that of the control and drug groups. The immunohistochemistry results are as follows: α7nAChR-positive cells and optical density in the hippocampus of the rats in the test group are less than that of the rats in the control and drug groups (all P < 0.01). Arborvitae seed can treat AD by increased expression of α7nAChR.     

Surface Properties and Corrosion Behavior of Co–Cr Alloy Fabricated with Selective Laser Melting Technique

We sought to study the corrosion behavior and surface properties of a commercial cobalt–chromium (Co–Cr) alloy which was fabricated with selective laser melting (SLM) technique. For this purpose, specimens were fabricated using different techniques, such as SLM system and casting methods. Surface hardness testing, microstructure observation, surface analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test were carried out to evaluate the corrosion properties and surface properties of the specimens. We found that microstructure of SLM specimens was more homogeneous than that of cast specimens. The mean surface hardness values of SLM and cast specimens were 458.3 and 384.8, respectively; SLM specimens showed higher values than cast ones in hardness. Both specimens exhibited no differences in their electrochemical corrosion properties in the artificial saliva through potentiodynamic curves and EIS, and no significant difference via XPS. Therefore, we concluded that within the scope of this study, SLM-fabricated restorations revealed good surface properties, such as proper hardness, homogeneous microstructure, and also showed sufficient corrosion resistance which could meet the needs of dental clinics.     

Molecular Cloning, Co-expression, and Characterization of Glycerol Dehydratase and 1,3-Propanediol Dehydrogenase from Citrobacter freundii

1,3-Propanediol (1,3-PD), an important material for chemical industry, is biologically synthesized by glycerol dehydratase (GDHt) and 1,3-propanediol dehydrogenase (PDOR). In present study, the dhaBCE and dhaT genes encoding glycerol dehydratase and 1,3-propanediol dehydrogenase respectively were cloned from Citrobacter freundii and co-expressed in E. coli. Sequence analysis revealed that the cloned genes were 85 and 77 % identical to corresponding gene of C. freundii DSM 30040 (GenBank No. U09771), respectively. The over-expressed recombinant enzymes were purified by nickel-chelate chromatography combined with gel filtration, and recombinant GDHt and PDOR were characterized by activity assay, kinetic analysis, pH, and temperature optimization. This research may form a basis for the future work on biological synthesis of 1,3-PD.     

PTEN overexpression promotes glioblastoma death through triggering mitochondrial division and inactivating the Akt pathway

Abstract

Objective: PTEN has been acknowledged as an anticancer factor in the progression of glioblastoma. Mitochondrial division has been found to be associated with cancer cell death.

Objective: The aim of our study is to explore whether PTEN attenuates the development of glioblastoma by modulating mitochondrial division.

Materials and methods: PTEN adenovirus was used to overexpress PTEN in U87 cells. Mitochondrial function was detected via western blot and immunofluorescence. Pathway blocker was used to inhibit the Akt activation.

Results: The results of our study demonstrated that PTEN overexpression reduced cell viability by increasing cell apoptosis. At the molecular level, PTEN overexpression activated mitochondrial apoptosis by mediating mitochondrial dysfunction. Furthermore, we found that Drp1-related mitochondrial division was required for PTEN-mediated mitochondrial dysfunction and cell death. Finally, we found that PTEN modulated Drp1-related mitochondrial division via the Akt pathway; inactivation of Akt induced cell death, and mitochondrial damage, similar to the results obtained via PTEN overexpression.

Conclusions: Taken together, our results clarify that the anticancer mechanism of PTEN in glioblastoma is dependent on the activation of Drp1-related mitochondrial division via Akt pathway modulation. This finding might provide new insight into the tumor-suppressive role played by PTEN in glioblastoma.     

Complex Interaction and Adsorption of Glyphosate and Lead in Soil

Glyphosate [N-(phosphonomethyl)-glycine] is a herbicide widely used in large quantities in agricultural applications. It is also known to form complexes with metal ions, although its influence on metal behavior, such as lead (Pb) in soil, is not well understood. In this study, the adsorption and co-adsorption of Pb and glyphosate were determined on two soils [a red (RS) soil, Udic Ferrisol, and a yellow-brown (YB) soil, Udic Luvisol] of distinctly different chemical characteristics at varying pH conditions. Results indicate that the adsorption of lead and glyphosate strongly depends on soil types: the RS soil, characterized by a relatively high iron/aluminum content but a low pH and organic matter content, shows a much lower adsorption capacity for Pb but a higher sorption for glyphosate than the YB soil. The co-existence of Pb and glyphosate in soils resulted in complex interactions among Pb, glyphosate, Pb-glyphosate complexes, and soil minerals. The presence of glyphosate decreased Pb adsorption on the two soils, which was attributed primarily to the formation of soluble Pb-glyphosate complexes having relatively low affinities to soil surfaces. On the other hand, addition of Pb increased the adsorption of glyphosate on both soils, which was attributed to: (1) a decreased solution pH due to the ion exchange between Pb²⁺ and H⁺ on soil surfaces; and (2) increased sorption sites where Pb was adsorbed and acted as a bridge between glyphosate and the soil. The present study illustrates that the complex interactions among glyphosate, Pb, and soil may have important implications for the mobility and bioavailability of Pb in soil and should thus be considered in future environmental risk assessments.