玉米AGO基因在籽粒发育过程中的表达分析

以玉米自交系‘昌7-2’授粉后4个时间点(授粉后7、10、14和20d)的籽粒总RNA为研究对象,采用实时荧光定量PCR技术,对玉米中5个Argonaute(AGO)蛋白家族基因(AGO1、AGO2、AGO4、AGO10和AGO18)在籽粒不同发育时期的表达谱进行了研究。结果表明:AGO1和AGO2在籽粒发育过程中呈现一致的表达趋势,在授粉后7d的籽粒中表达量最高,从授粉后7d到20d呈持续下降的趋势。AGO4、AGO10和AGO18具有一致的表达趋势,均呈现先下降后上升的趋势,在授粉后10d的籽粒中表达量最低。结合实验室前期获得的miRNA在玉米籽粒不同发育阶段的表达谱,发现不同AGO家族基因可协助其靶标miRNA参与玉米籽粒发育调控。     

Gene polymorphisms of SFTPB rs7316, rs9752 and PAOX rs1046175 affect the diagnostic value of plasma Pro-SFTPB and DAS in Chinese Han non–small-cell lung cancer patients

Plasma pro-surfactant protein B (pro-SFTPB) and N1,N12-diacetylspermine (DAS) can be used as markers for the diagnosis of non–small-cell lung carcinoma (NSCLC). Whether the genetic diversity affects the application value of Pro-SFTPB and DAS as a diagnostic marker for NSCLC is still unknown. This study aims to explore the relationship between SFTPB rs7316, rs9752 and PAOX rs1046175 gene polymorphisms and the diagnostic value of plasma Pro-SFTPB and DAS in patients with Chinese Han lung cancer. SFTPB rs7316, rs9752 and PAOX rs1046175 genotypes were analyzed by direct sequencing in 425 patients with NSCLC and 425 controls, and the levels of Pro-SFTPB and DAS in plasma were determined by enzyme-linked immunosorbent assay (ELISA). The area under the curve (AUC) of the SFTPB rs7316 locus TT genotype for the diagnosis of NSCLC was 0.758, and the AUC of the TC/CC genotype for the diagnosis of NSCLC was 0.872. The AUC of the SFTPB rs9752 locus GG genotype for the diagnosis of NSCLC was 0.935, and the AUC of the GC/CC genotype for the diagnosis of NSCLC was 0.648. The AUC of the PAOX rs1046175 locus GG for the diagnosis of NSCLC was 0.669, and the AUC of the GC/CC genotype for the diagnosis of NSCLC was 0.749. In conclusion, SFTPB rs7316, rs9752, and PAOX rs1046175 gene polymorphisms affect the diagnostic value of plasma Pro-SFTPB and DAS in patients with Chinese Han NSCLC.     

Heme oxygenase-1 prevents smoke induced B-cell infiltrates: a role for regulatory T cells?

Background

Smoking is the most important cause for the development of COPD. Since not all smokers develop COPD, it is obvious that other factors must be involved in disease development. We hypothesize that heme oxygenase-1 (HO-1), a protective enzyme against oxidative stress and inflammation, is insufficiently upregulated in COPD.The effects of HO-1 modulation on cigarette smoke induced inflammation and emphysema were tested in a smoking mouse model.

Methods

Mice were either exposed or sham exposed to cigarette smoke exposure for 20 weeks. Cobalt protoporphyrin or tin protoporphyrin was injected during this period to induce or inhibit HO-1 activity, respectively. Afterwards, emphysema development, levels of inflammatory cells and cytokines, and the presence of B-cell infiltrates in lung tissue were analyzed.

Results

Smoke exposure induced emphysema and increased the numbers of inflammatory cells and numbers of B-cell infiltrates, as well as the levels of inflammatory cytokines in lung tissue. HO-1 modulation had no effects on smoke induced emphysema development, or the increases in neutrophils and macrophages and inflammatory cytokines. Interestingly, HO-1 induction prevented the development of smoke induced B-cell infiltrates and increased the levels of CD4⁺CD25⁺ T cells and Foxp3 positive cells in the lungs. Additionally, the CD4⁺CD25⁺ T cells correlated positively with the number of Foxp3 positive cells in lung tissue, indicating that these cells were regulatory T cells.

Conclusion

These results support the concept that HO-1 expression influences regulatory T cells and indicates that this mechanism is involved in the suppression of smoke induced B-cell infiltrates. The translation of this interaction to human COPD should now be pursued.     

喀斯特小流域土壤有机碳空间异质性及储量估算方法

为了准确估算土壤有机碳储量,利用网格法采集2755个土壤剖面,共计23536个土壤样品,研究了喀斯特小流域土壤有机碳含量分布特征,并以"土壤类型法"为基准,对土壤分布面积、石砾含量、岩石裸露率、土层厚度等指标进行修正,合理的优化了土壤有机碳储量计算公式,探索出一种专属于喀斯特地区土壤有机碳储量的估算方法,结果表明:不同土层深度和土壤类型下土壤有机碳含量存在明显差异,土壤有机碳含量随着土层深度的增加而逐渐减小,不同土属的有机碳含量减小的幅度有所差异,不同坡位和坡向的有机碳含量大小为:阳坡阴坡,坡中上部坡顶坡中坡中下坡坡底,不同土地利用方式下土壤有机碳含量大小顺序为:林地灌草地旱地水田;土壤有机碳含量与坡度、海拔、岩石裸露率均呈极显著正相关关系,与土层厚度、土壤容重呈显著负相关;喀斯特地区土壤异质性较大,不同修正指标对土壤有机碳储量估算的影响程度为:土壤厚度岩石裸露率石砾含量土壤有机碳含量土壤容重;通过修正后的计算公式估算出普定后寨河小流域表层20 cm土壤有机碳密度区间为3.53—5.44 kg/m~2,平均值为:1.24 kg/m~2,100 cm土壤有机碳密度区间为4.44—14.50 kg/m~2,平均值为12.12 kg/m~2,土壤有机碳储量为5.39×10~5t。     

Role of macrophage colony-stimulating factor in the differentiation and expansion of monocytes and dendritic cells from CD34+ progenitor cells

The present study focused on whether it is possible to expand monocytic cells from CD34⁺ progenitor cells by using macrophage colony-stimulating factor (M-CSF) in the absence and presence of mast cell growth factor (MGF) and IL-6. It was demonstrated that CD34⁺ cells differentiate without expansion to functional mature monocytic cells in the presence of M-CSF or combinations of M-CSF plus IL-6 and MGF. A different response pattern was observed for the number of clonogenic cells. The addition of IL-6 or both IL-6 and MGF to M-CSF containing cultures resulted in significant higher numbers of colony-forming unit-macrophage (CFU-M) as tested in clonogenic and³H-thymidine assays. Furthermore, M-CSF plus both IL-6 and MGF appeared to be the most potent combination to preserve the monocytic precursor in cell suspension culture assays. These results indicate that IL-6 and MGF in conjunction with M-CSF affect CD34⁺ cells especially at precursor level without distinct effect on the more mature stages. Secondly we studied whether M-CSF is only critical for the monocytic lineage or also affects dendritic cell (DC) development. Indeed, we were able to culture CD83⁺ DC from CD34⁺ progenitor cells in the presence of M-CSF in conjunction with TNF-α, IL-4, and MGF although their absolute number is almost threefold lower than the number of CD83⁺ cells yielded from GM-CSF plus TNF-α, IL-4, and MGF stimulated CD34⁺ cells.     

A study of the suitability of gas chromatography-electron capture detection for the analysis of deoxynivalenol in cereals

A gas chromatographic-electron capture detection (GC-ECD) method for the analysis of deoxynivalenol (DON) in cereals was investigated. The sample was extracted with a mixture of acetonitrile-water and purified with a MycoSep #225 column. The silylation was performed with Tri-Sil-TBT reagent, followed by dilution with hexane and a washing step with buffer. By using Tri-Sil-TBT reagent no double peaks were observed for DON in the gas chromatograms, in comparison with two other silylation reagents TMSI and Tri-Sil-Z. The use of trichothecolone (TRI) as an internal standard for DON was studied in order to indicate possible problems in the derivatisation reaction. TRI proved to be a relatively good internal standard for DON in cereal samples, as well as 1,1-bis-(4-chlorophenyl)-2,2-dichloroethylene (DDE), which was used as a GC standard for ensuring the function of GC-ECD. During the study, a matrix effect was clearly observed between the cereal matrix-assisted calibration curve and the calibration curve prepared without cereal matrix. The results of spiked and reference material samples, quantified with the calibration curve prepared without and with matrix, demonstrated that the matrix affects the results. However, after recovery correction the results were comparable. The validation results demonstrated that the GC-ECD method for DON analysis in cereals is sufficiently reliable.     

Dysregulation of ferroptosis may involve in the development of non-small-cell lung cancer in Xuanwei area

The Xuanwei area of Yunnan Province, China, is one of the regions suffering from the highest occurrence and mortality rate of lung cancer in the world. Local residents tend to use bituminous coal as domestic fuel, which causes serious indoor air pollution and is established as the main carcinogen. After the local government carried out furnace and stove reform work, lung cancer rate including incidence and mortality among residents remains high. We herein wonder if there are specific mechanisms at protein level for the development of non-small-cell lung cancer (NSCLC) in this area. We investigated the changes of protein profiling in tumour of the patients from Xuanwei area. Tandem mass tag (TMT) was employed to screen the differential proteins between carcinoma and para-carcinoma tissues. We identified a total of 422 differentially expressed proteins, among which 162 proteins were significantly up-regulated and 260 were downregulated compared to para-carcinoma tissues. Many of the differentially expressed proteins were related to extracellular matrix (ECM)-receptor interaction, focal adhesion, PI3K/AKT pathway and ferroptosis. Further experiments on the two differential proteins, thioredoxin 2 (TXN2) and haptoglobin (HP), showed that the change of their expressions could make the lung cancer cell lines more resistant to erastin or RSL-induced ferroptosis in vitro, and promote the growth of tumour in nude mice. In conclusion, this study revealed that aberrant regulation of ferroptosis may involve in the development of lung cancer in Xuanwei area.     

Heat Shock Protein 70 Prevents Hyperoxia-Induced Disruption of Lung Endothelial Barrier via Caspase-Dependent and AIF-Dependent Pathways

Exposure of pulmonary artery endothelial cells (PAECs) to hyperoxia results in a compromise in endothelial monolayer integrity, an increase in caspase-3 activity, and nuclear translocation of apoptosis-inducing factor (AIF), a marker of caspase-independent apoptosis. In an endeavor to identify proteins involved in hyperoxic endothelial injury, we found that the protein expression of heat-shock protein 70 (Hsp70) was increased in hyperoxic PAECs. The hyperoxia-induced Hsp70 protein expression is from hspA1B gene. Neither inhibition nor overexpression of Hsp70 affected the first phase barrier disruption of endothelial monolayer. Nevertheless, inhibition of Hsp70 by using the Hsp70 inhibitor KNK437 or knock down Hsp70 using siRNA exaggerated and overexpression of Hsp70 prevented the second phase disruption of lung endothelial integrity. Moreover, inhibition of Hsp70 exacerbated and overexpression of Hsp70 prevented hyperoxia-induced apoptosis, caspase-3 activation, and increase in nuclear AIF protein level in PAECs. Furthermore, we found that Hsp70 interacted with AIF in the cytosol in hyperoxic PAECs. Inhibition of Hsp70/AIF association by KNK437 correlated with increased nuclear AIF level and apoptosis in KNK437-treated PAECs. Finally, the ROS scavenger NAC prevented the hyperoxia-induced increase in Hsp70 expression and reduced the interaction of Hsp70 with AIF in hyperoxic PAECs. Together, these data indicate that increased expression of Hsp70 plays a protective role against hyperoxia-induced lung endothelial barrier disruption through caspase-dependent and AIF-dependent apoptotic pathways. Association of Hsp70 with AIF prevents AIF nuclear translocation, contributing to the protective effect of Hsp70 on hyperoxia-induced endothelial apoptosis. The hyperoxia-induced increase in Hsp70 expression and Hsp70/AIF interaction is contributed to ROS formation.