Effect of CHOP expression knock-down on apoptosis of renal tubular epithelial cells

AIM:To study the effect of C/EBP homologous protein (CHOP) on the apoptosis of renal tubular epithelial HK2 cells. METHODS:The serum mRNA levels of CHOP in the patients with acute kidney injury and healthy controls were detected by qPCR. In vitro, renal tubular epithelial HK2 cells were divided into control group, negative group (transfected with negative control siRNA), si-CHOP group (transfected with CHOP siRNA), and induced by transforming growth factor-β1 (TGF-β1). The viability of the cells was measured by MTT assay, and the apoptotic rate was analyzed by flow cytometry. The protein levels of nuclear antigen Ki-67, proliferating cell nuclear antigen (PCNA), caspase-3 and cleaved caspase-3 were determined by Western blot. RESULTS:Compared with the healthy controls, the serum mRNA levels of CHOP in the patients with acute kidney injury were increased significantly (P<0.05). Transfection with CHOP siRNA significantly decreased the expression of CHOP in the renal tubular epithelial HK2 cells (P<0.05). Knock-down of CHOP expression by siRNA significantly increased the viability of renal tubular epithelial HK2 cells (P<0.05), decreased the apoptotic rate (P<0.05), increased the expression of Ki-67 and PCNA (P<0.05), and down-regulated the protein level of cleaved caspase-3 (P<0.05). CONCLUSION:The serum mRNA levels of CHOP were increased in the patients with acute kidney injury. Knock-down of CHOP expression inhibits the apoptosis of renal tubular epithelial cells by regulating the expression of proliferation-and apoptosis-related proteins.     

Role of cytokeratin 8 on changes of intestinal epithelial permeability induced by corticotropin-releasing factor

AIM: To investigate the role of cytokeratin 8 (CK8) on the change of intercellular permeability of intestinal epithelial cells induced by corticotropin-releasing factor (CRF). METHODS: The expression levels of CRF receptor 1 (CRFR1) and CRFR2 on human colon adenocarcinoma HT29 cell surface were determined by immunofluorescence staining. After treatment with 100 nmol/L CRF for 72 h, the translocation of FITC-labelled dextran was measured in a Transwell chamber. The structural changes of tight junctions were observed under transmission electron microscope. The expression levels of CK8, and tight junction proteins ZO-1 and occludin were determined by Western blot. The activity of protein kinase C (PKC) was detected by ELISA. Furthermore, the effects of CRF on intestinal epithelial permeability were examined in CK8-silencing HT29 cells, which were constructed by infection with sh-CK8 lentivirus. RESULTS: CRF treatment increased the permeability of FITC-labelled dextran (P<0.05), caused the opening of tight junctions, and induced increased fluorescence intensity of CK8. The expression levels of occludin and ZO-1 were down-regulated (P<0.05). PKC activity was decreased at 1 h after CRF treatment (P<0.05). CRF-induced increase in the permeability and down-regulation of occludin were not blocked by CK8 silencing. Nevertheless,CK8 silencing blocked the effects of CRF regarding the decrease in the expression levels of ZO-1 and the increase in PKC activity (P<0.05). CONCLUSION: CK8 may be involved in CRF-induced increase in intestinal epithelial permeability by inhibiting the activity of PKC, and there may be other signaling pathways involved.     

FAM3C activates Akt to promote viability of oral squamous-cell carcinoma cells

AIM: To investigate the expression and roles of family with sequence similarity 3, member C (FAM3C) in oral squamous-cell carcinoma cells. METHODS: The mRNA and protein expression levels of FAM3C in dysplastic oral keratinocyte (DOK) and oral squamous-cell carcinoma WSU-HN6 cells were detected by RT-qPCR and Western blot. The WSU-HN6 cells were treated with siFAM3C or FAM3C antibody. After 24, 48 and 72 h, the viability of WSU-HN6 cells was measured by CCK-8 assay, and the activation of protein kinase B (Akt) was detected by Western blot. Adenovirus was used to mediate over-expression of FAM3C in the DOK cells. The DOK cell viability was measured by CCK-8 assay after adenovirus infection for 24, 48 and 72 h, and the activation of Akt was detected by Western blot. RESULTS: Compared with the DOK cells, the mRNA and protein levels of FAM3C were significantly increased in the WSU-HN6 cells (P<0.05). The viability of WSU-HN6 cells transfected with siFAM3C was significantly inhibited at 48 h and 72 h (P<0.05). siFAM3C treatment inhibited the activation of Akt (P<0.05). FAM3C antibody treatment also suppressed the viability of the WSU-HN6 cells at 48 h and 72 h and the activation of Akt (P<0.05). Over-expression of FAM3C in the DOK cells promoted the cell viability at 48 h and 72 h and activated Akt (P<0.05). CONCLUSION: FAM3C might promote oral squamous-cell carcinoma cell growth by activating Akt.     

Effects of DHRS3 in C2C12 Myoblast Differentiation and Mouse Skeletal Muscle Injury

Myoblast differentiation is an essential process during skeletal muscle development. C2 C12 myoblast is a commonly used experimental model to study muscle cell differentiation in vitro. Dehydrogenase/reductase(SDR family) member 3(DHRS3) is a highly conserved member in short-chain alcohol dehydrogenase/reductase superfamily and has been shown to be involved in the metabolism of retinol. Previous experimental results showed that the expression of DHRS3 increased significantly during the differentiation of myoblasts differentiation. However, the effect of DHRS3 on mouse muscle cell differentiation was unclear. The objective of current study was to determine if DHRS3 affected muscle cell differentiation, and if DHRS3 was involved in muscle regeneration. Protein expression was determined by western blot and immunofluorescence analysis. The activation and inhibition of DHRS3 increased and decreased C2 C12 myoblast differentiation respectively, which indicated that DHRS3 could affect C2 C12 myoblast differentiation. DHRS3 expression was significantly changed during muscle regeneration, with the regeneration of muscle injury, the expression of DHRS3 tended to increase first and then decrease. It suggested that DHRS3 might be involved in muscle regeneration. In summary, this study confirmed the involvement of DHRS3 in C2 C12 myoblast differentiation and mouse skeletal muscle regeneration and provided a theoretical basis for further elucidating the molecular mechanism of muscle development.     

开垦草地对土壤有机碳库构成与来源的效应

以广西西北部喀斯特地区的开垦草地生态系为对象,研究了草地开垦变为不同农田后对土壤有机碳库的效应。结果表明,草地开垦为农田后,土壤可溶性有机碳、微生物生物量碳及总有机碳的含量显著下降。自然草地开垦后,柑桔地土壤有机碳含量高于农作用地土壤。玉米与甘蔗轮作土壤有机碳含量高于甘蔗连作。13C示踪结果表明,柑桔地土壤有机碳中来源于草地的含量高于农田土壤;农田土壤有机碳中来源于草地的随种植年限的增加而降低。在玉米与甘蔗轮作的农田中,土壤有机碳中来源于玉米的高于甘蔗连作土壤有机碳中来源于甘蔗的。     

成熟期库尔勒香梨理化指标变化规律及相关性研究

为了研究库尔勒香梨成熟过程中理化指标的变化规律,探求成熟期库尔勒香梨主要理化指标间的相关性,以成熟期库尔勒香梨为研究对象,研究库尔勒香梨果实硬度、叶绿素含量、SSC(可溶性固形物含量)和维生素C含量的变化规律;采用相关分析和回归分析的方法,应用Spss软件和Excel软件对指标均值以及各指标间相关性进行了分析,并对试验结果进行了实验验证。研究结果表明:在成熟期内,库尔勒香梨果实理化参数变化范围分别为:硬度4.23~7.99 kg/cm2、叶绿素3.17~6.54 mg/100 g、SSC11.54%~15.41%、维生素C 1.9~4.2 mg/1 0 0 g;随着成熟的深入,果实硬度逐渐降低、叶绿素含量逐渐减少、SSC逐渐增加、维生素C含量逐渐增加;各指标均值在0.01水平上显著相关。回归分析过程中选取最优的拟合方式,并建立相应的数学模型,果实硬度和SSC与叶绿素含量和维生素C含量间决定系数均大于0.95,验证试验预测值与测量值误差小于3.2 1%,在库尔勒香梨成熟过程中可应用果实硬度和SSC对叶绿素和维生素C含量进行预测。研究结果能够为库尔勒香梨成熟度评价和分级提供参考。     

农田管理措施对滨海盐渍化土壤碳平衡的影响

为研究不同农田管理措施对滨海盐渍土壤碳平衡的影响,通过玉米-小麦轮作试验,研究农田土壤碳收支情况。试验共设6个处理:(1)常规对照(CK),(2)有机肥常量(OF),(3)氮肥增施(NF),(4)秸秆还田(S),(5)有机肥加秸秆(OF+S),(6)免耕(NT)。结果表明,秸秆还田和施用有机肥提高了土壤呼吸的强度,而NT处理的CO_2平均释放量最低,不同处理下土壤呼吸表现为OF+S处理S处理OM处理NF处理CKNT处理。各处理土壤有机碳量随着作物种植年份的增加而逐渐升高,其中OF与NT处理增加最多,而NF处理并没有显著提高土壤的有机碳量。在两季作物收获后,各处理的碳输入均高于碳输出,表现为碳净输入,呈现较强的碳汇特征。S处理和OF处理的碳净输入均显著高于CK,可有效减缓土壤CO_2排放,增加其有机碳的输入。     

土壤不同粒级中C、N、P、K的分配及N的有效性研究

本试验首先把７种采自不同省份的耕作土壤进行物理分级,然后测定了土壤Ｃ、Ｎ、Ｐ、Ｋ在不同粒级中的分布,同时还进行不同粒有中Ｎ的有效笥研究。结果表明：在不同粒级中Ｃ、Ｎ含量和分布均随土壤颗粒的加粗而逐渐下降,血Ｃ／Ｎ比则与此相反。在〈２μｍ粒级中Ｎ的有效性最高,随着土壤颗粒粒和戏的加粗有效性逐渐降低,在酸性土壤中Ｐ主要分布在较细的粒级中,而在石灰性土壤中则粗有效性逐渐降低。在酸性土壤中Ｐ主要分布在较细     

施肥对土壤不同碳形态及碳库管理指数的影响

分析了施肥对土壤活性碳（ＣＡ）、微生物生物量碳（ＣＭＢ）、矿化碳（ＣＭ）及碳库管理指数（ＣＰＭＩ）的影响。结果表明,不同土壤ＣＡ、ＣＭＢ、ＣＭ及ＣＰＭＩ的大小为：水稻土〉黄棕壤〉红壤〉潮土。施肥对ＣＡ和ＣＰＭＩ,ＣＭＢ和ＣＭ的影响分别为：处理３〉处理〉处理１〉处理４〉ＣＫ,处理３〉处理５〉处理４〉处理１〉ＣＫ。在提高ＣＡ、ＣＭＢ、ＣＭ及ＣＰＭＩ方面,稻草肥、绿肥优于厩肥,厩肥高量施用优于常量施用。     

Stable C and N isotope values of selected components of a tropical australian sugarcane ecosystem

The ¹³C and ¹⁵N values of sugarcane plant tissues, decomposing harvest residues, soil and the casts and body tissues of the earthwormPontoscolex corethrurus were determined. Little variation in ¹³C values was found between plant parts. The ¹³C values of the decomposing harvest residues declined and became more variable after 148 days of exposure in the field. In the decomposing residues, ¹³C values of the neutral detergent fibre fraction were similar to those of the whole tissues while those of the proximate lignin were more negative. The ¹⁵N values of the residues also declined over time after a short initial delay.P. corethrurus populations are more intimately associated with the roots of sugarcane than with the bulk soil. Tissue ¹³C values suggest that the earthworm diet is similar to or more enriched in¹³C than sugarcane tissues and is substantially more enriched than the soil C. Earthworm tissues have similar levels of¹⁵N enrichment to both the soil and plant tissues. These data are consistent with the hypothesis that this earthworm derives much of its assimilated C relatively directly from organic matter associated with the roots and decomposing harvest residues.