Overload of ferric ammonium citrate triggers MAPK pathways by producing high level of reactive oxygen species and induces apoptosis of human hFOB1.19 osteoblast cells

AIM：To investigate the role of reative oxygen species (ROS) generated by iron overload in activating the mitogen-activated protein kinase (MAPK) pathways and apoptosis. METHODS：Cultured human osteoblast cell line hFOB1.19 was treated with ferric ammonium citrate (FAC) at concentrations of 0~500 μmoL/L. The proliferation of hFOB1.19 cells was analyzed by MTT assay. Apoptosis was detected by flow cytometry with Annexin V/PI staining. The expression levels of p-ERK, p-JNK and p-p38 were determined by Western blotting 24 h after treatment with FAC. RESULTS：After treated with FAC, the cell proliferation was inhibited. The early apoptosis and total cell death were significantly increased. The levels of ROS were increased to (35.73±2.52)%, (62.89±4.24)% and (76.06±3.55)% with the increasing doses of FAC treatmen,respectively. The expression levels of p-ERK, p-JNK and p-p38 were also remarkably elevated in FAC groups. CONCLUSION：Iron overload increases intracellular ROS level, thus triggering the MAPK pathways and inducing apoptosis of human hFOB1.19 osteoblast cells.     

Differentially expressed genes identified through RNA‐seq with extreme values of principal components for beef fatty acid in Nelore cattle

The aim of this study was to identify differentially expressed genes (DEG) in the Longissimus thoracis muscle of Nelore cattle related to fatty acid (FA) profile through RNA sequencing and principal component analysis (PCA). Two groups of 10 animals each were selected containing PC1 and PC2 extreme DEG values (HIGH × LOW) for each FA group. The intramuscular fat (IMF) was compared between cluster groups by ANOVA, and only the sum of monounsaturated FA (MUFA) and ω3 showed significant differences (p < .05). Interestingly, the highest percentage (95%) of phenotypic variation explained by the sum of the first two PC was observed for ω3, which also displayed the lowest number of DEG (n = 1). The lowest percentage (59%) was observed for MUFA, which also revealed the largest number of DEG (n = 66). Since only MUFA and ω3 exhibited significant differences between cluster groups, we can conclude that the differences observed for the remaining groups are not due to the percentage of IMF. Several genes that have been previously associated with meat quality and FA traits were identified as DEG in this study. The functional analysis revealed one KEGG pathway and eight GO terms as significant (p < .05), in which we highlighted the purine metabolism, glycolytic process, adenosine triphosphate binding and bone development. These results strongly contribute to the knowledge of the biological mechanisms involved in meat FA profile of Nelore cattle.     

纤维素超低酸水解产物的分析

基于木质纤维素类生物质水解为人类提供乙醇等能源、化工产品的重要性，该文以定量滤纸模拟生物质的主要组分－纤维素，以其超低酸水解试验得到的最佳工况下液体产物和固体残渣为研究对象，通过高效液相色谱(HPLC)结合KS-802糖柱对产物质中糖的种类进行了划分，以GC-MS对副产物进行定性，并通过扫描电镜(SEM)及热重和工业分析元素分析对固体残渣作了从表观到内部的研究，发现纤维素超低酸水解主要生成纤维四糖、三糖和二糖等低聚糖和葡萄糖及果糖，反应副产物有糠醛、羟甲基糠醛、乙酰丙酸及一些小分子酮、醛类和酸类极性化合物，水解残渣已完全改变了原始形貌，热裂解活性增强，残留物中碳和灰分含量有较大增加，最后根据分析结果探讨了纤维素超低酸水解的反应途径，为木质纤维素类生物质水解技术的规模化利用打下基础。     

Degradability of atrazine, cyanazine, and dicamba in methanogenic enrichment culture microcosms using sediment from the Pearl River of Southern China

Degradation of three herbicides, atrazine, cyanazine and dicamba, was assessed in laboratory microcosms incubated under simulated methanogenic conditions using sediment from Pearl River of Southern China as an inoculum. Atrazine was much more resistant to degradation than cyanazine and dicamba over 300 days of incubation. Biodegradation of cyanazine and dicamba was further substantiated by establishment of enrichment transfer cultures in which the degradation of the respective herbicide was accelerated by the active microorganisms. Degradation of cyanazine initially involved the removal of chlorine and the two side chains, while that of dicamba was O-demethylation reaction forming 3,6-dichlorosalicyclic acid. Results suggest that biodegradation of xenobiotics can be established through enrichment culture transfer technique, and further mechanism of degradation and microorganisms involved can be elucidated.     

土壤类型对优先流路径和磷形态影响的定量评价

以中国贡嘎山由青灰色砂质冰水堆积物发育而成的疏松岩性土壤和德国厄尔士山渍水土壤优先流路径为研究对象,通过野外染色示踪试验和改进的Hedley磷形态提取法,使用优先流染色面积比和优先流程度评价指数定量评价不同类型土壤的优先流程度,通过相关关系分析进一步揭示不同土壤类型中优先流路径对磷形态分布的影响。结果表明:贡嘎山和厄尔士山优先流图片总染色面积比分别为31%和52%,厄尔士山渍水土优先流比贡嘎山疏松岩性土发育较好。贡嘎山疏松岩性土壤优先流发育程度与潜在生物可利用无机磷和有机磷贡献率显著正相关,而即时生物有效无机磷和磷灰石磷与厄尔士山渍水土壤优先流发育程度显著正相关。土壤类型影响优先流路径分布和土壤磷形态分布,从而影响土壤磷赋存状况和下游水质安全。     

Effect of tetrandrine on radiosensitivity of nasopharyngeal carcinoma cells

AIM: To investigate the mechanism of the radiosensitizing effect of maximum non-cytotoxic doses of tetrandrine (Tet) on nasopharyngeal carcinoma cell lines CNE1 and CNE2.METHODS: The cells were treated with ma-ximum non-cytotoxic doses of Tet (for CNE1 cells at 1.5 μmol/L and for CNE2 cells at 1.8 μmol/L), irradiation at 4 Gy, or combination of irradiation and maximum non-cytotoxic doses of Tet. The cell cycle distribution was analyzed by flow cytometry. The protein levels of γ-H2AX, cleaved caspase-3, p-CDC25C, CDK1, p-CDK1, cyclin B1, ERK and p-ERK were determined by Western blot.RESULTS: The expression of γ-H2AX was increased in CNE1 cells and CNE2 cells after combined treatment with irradiation and maximum non-cytotoxic doses of Tet. The percentages of CNE1 cells and CNE2 cells at G₂/M phase in irradiation group were (18.09±0.42)% and (18.48±1.32)%, respectively, which were decreased to (15.88±1.04)% and (13.80±0.82)% in combined treatment group, respectively (P<0.05). Combined treatment enhanced the increase in the protein level of cleaved caspase-3 caused by irradiation. The protein levels of p-CDC25C and p-CDK1 were increased in a dose-dependent manner by Tet treatment (P<0.05), while the expression of CDK1 showed no difference among different doses of Tet treatments. The protein levels of p-CDC25C, p-CDK1 and CDK1 showed no difference after the treatment with maximum non-cytotoxic doses of Tet. The combined treatment with irradiation and the maximum non-cytotoxic doses of Tet decreased the protein levels of p-CDC25C and p-CDK1 (P<0.05), increased the expression of cyclin B1, and had no influence on the expression of CDK1 (P<0.05). The combined treatment resulted in an increase in the protein level of p-ERK1 (P<0.05).CONCLUSION: The maximum non-cytotoxic doses of Tet enhance the DNA damage and apoptosis in CNE1 cells and CNE2 cells caused by irradiation, and the mechanism might be associated with ending of G₂/M arrest via activation of ERK/CDC25C/CDK1/cyclin B1 pathways.     

新烟碱类杀虫剂降解特性研究进展

新烟碱类杀虫剂是合成的具有较强杀虫能力的类烟碱衍生物,其已经发展成为世界上使用最广泛的一类杀虫剂。在过去的20年里,新烟碱类杀虫剂的环境残留由于大规模的应用而急剧增加。因此探究有效的新烟碱类杀虫剂的降解方法势在必行。新烟碱类杀虫剂的光解和水解及降解途径已有报道。与化学方法相比,生物修复是一种经济、环保的处理农药污染环境的方法。然而,关于微生物降解新烟碱类杀虫剂及其代谢途径和降解机制的研究较少。因此,本文就新烟碱类杀虫剂的化学和微生物降解及其降解机制进行综述,并对微生物降解新烟碱杀虫剂未来的研究重点和方向提出了展望。     

稻鸭共作中CH4和N2O排放规律及影响因素

稻鸭共作是目前稻田种养中的一种典型模式,其主要特点是利用鸭子在稻田内的活动,实现经济效益和生态效益的双赢。鸭子的存在丰富了生物多样性,充分利用了稻田生态位。鸭子的持续运动、觅食、排泄等活动会影响稻田温室气体甲烷(CH_4)和氧化亚氮(N_2O)的排放和全球增温潜势(GWP)。本文结合稻鸭共作中鸭子对稻田环境的扰动行为,从水体、土壤、CH_4和N_2O转化功能菌及种植技术等角度,总结探讨了稻鸭共作中温室气体CH_4和N_2O产生、输送和释放的过程与机理。针对当前稻鸭共作温室气体排放研究中存在的问题,提出了一系列建议和展望,以期为稻田种养温室气体减排的研究提供参考。     

动物食欲调节的中枢信号通路

下丘脑是动物食欲调节的中枢，外周食欲信号在下丘脑中经食欲调节网络整合，产生饱感或饥饿。其中，以 ５′－磷酸腺苷激活的蛋白激酶（ＡＭＰＫ）调控位点上的 ＡＭＰＫ-ＡＣＣ-ＣＰＴ１和 ＵＣＰ２-ＦＯＸＯ１-ｐＣＲＥＢ信号通路以及雷帕霉素靶蛋白（ｍＴＯＲ）调控位点上的 ＰＩ３Ｋ-Ａｋｔ-ｍＴＯＲ和 ｍＴＯＲ-４ＥＢＰ１／ｐ７０Ｓ６Ｋ-ＮＰＹ／ＡｇＲＰ信号通路尤为重要。ＡＭＰＫ和 ｍＴＯＲ在 ＡＭＰＫ-ＴＳＣ ｍＴＯＲ通路、固醇类调节因子绑定蛋白（ＳＲＥＢＰ）基因表达和吞噬启动激酶（Ｕｌｋ１）活性通路上存在互作。外周营养和能量信号传输到下丘脑后，经过这些网络的传输和分析，作用于下丘脑中的食欲相关肽，最终调控动物的采食行为。     

肝脏与胰腺发育的分子调控

肝脏和胰腺均由内胚层发育而来的消化器官,它们广泛地参与糖代谢、脂类代谢和蛋白质代谢.肝脏和胰腺的发育是一个动态连续的过程,并受到多种信号途径及转录因子的调控.基于上述特点和显著的医用价值,笔者对肝脏和胰腺发育过程中的分子作用机理作了系统地阐述,这将不仅有助于理解与肝脏和胰腺相关疾病的发病机理.同时也为有效地指导相关疾病的预防及治疗工作提供分子理论基础.