UV-B辐射诱导芒果叶片抗氧化响应研究

为了解增强UV-B辐射诱导芒果叶片抗氧化响应的机制,以?台农1号?芒果(Mangifera indica?Tainong No. 1?)成年树为材料,以自然光为对照(CK),设置24和96 kJ/(m~2·d)两个增强UV-B辐射处理水平,观测叶片生理生化指标的动态变化。结果表明,24k J/(m~2·d)处理的芒果叶片MDA含量、相对电导率、净光合速率、抗氧化酶活性、多酚、Vc和芒果苷含量均与对照没有显著差异,而类黄酮和还原型GSH含量显著高于对照;而96 kJ/(m~2·d)处理的芒果叶片MDA含量、相对电导率、抗氧化酶活性及多酚、类黄酮、还原型GSH、芒果苷等还原型保护成分的含量均显著高于对照,而净光合速率和Vc含量均显著低于对照。因此,24 kJ/(m~2·d) UV-B辐射未引起?台农1号?芒果成年树损伤,可能是通过提高类黄酮和还原型GSH的含量来清除活性氧自由基;96 kJ/(m~2·d)处理则引起叶片活性氧损伤,但仍可能以两种机制减轻损伤,一是通过增强抗氧化酶活性和提高还原性成分含量来清除活性氧自由基,二是利用芒果苷、类黄酮和还原型GSH等成分吸收UV-B辐射。     

重组葡激酶对小型猪冠脉血栓的溶栓作用研究*

目的: 评价重组葡激酶的溶栓效力,并与相同作用方式的重组链激酶进行比较。方法: 30只中国实验小型猪分成5组,分别为溶剂对照组、阳性药对照组和三个重组葡激酶组,每组6只,采用麻醉动物、手术开胸、直流电刺激形成冠脉血栓;在冠脉血栓形成30 min后开始静脉给药,采用先推注、再蠕动泵恒速输注的方式给药;溶剂对照组静脉推注对照液,阳性药对照组静脉给予重组链激酶4 mg·kg^-1,三个重组葡激酶组分别静脉给予4 mg·kg^-1、2 mg·kg^-1、1 mg·kg^-1重组葡激酶,静脉推注体积为5 ml,1 min内注毕,输注速度为0.5 ml·min^-1,60 min内输毕,120 min后放血处死动物。于给药前及给药后30、60、120 min取静脉血,实验结束后取血栓形成部位的冠脉血管段,分别检测优球蛋白溶解时间(ELT)、血纤维蛋白原含量(Fbg)、纤维蛋白(原)降解产物(FDP)和伤口出血量,检测冠脉血栓溶解率、心肌缺血程度及缺血范围。结果: 与溶剂对照组相比,试验组ELT明显缩短(P＜0.05或P＜0.01),FDP 明显升高(P＜0.05或P＜0.01),较少量实验动物Fbg降解超过20%,对小型猪血压及心率无明显影响。与对照组相比,试验组高、中2个剂量组,最大血栓面积分别减少34.3%、15.4%(P＜0.05)。与等剂量的重组链激酶相比,重组葡激酶对电刺激引起的冠脉血栓具有更强的溶栓作用(P＜0.05或P＜0.01),引起的出血副反应少。结论: 重组葡激酶对小型猪冠脉血栓有较好的溶栓作用,相比重组链激酶,溶栓速度快、具有更高的纤维蛋白专一性,出血副反应较少。综合比较, 2 mg·kg^-1重组葡激酶具有较好的临床疗效和安全性保障。     

农业主产区湖泊水质对湖滨带多尺度景观格局的空间响应

为分析农业主产区湖泊水环境质量对不同空间尺度上景观格局的响应关系,以洪湖为研究对象,以5种湖泊功能区为基础,利用RS和GIS软件生成7种空间尺度的湖滨带缓冲区,采用Fragstats 软件分析景观格局指数,结合冗余分析等数理统计方法与模型,研究景观格局对洪湖水质变化的空间尺度效应。结果表明: 1)景观格局在不同宽度缓冲区内对湖泊水质的影响具有空间尺度性,在200 m宽度其解释能力最大,达到86.1%,是影响水质的最有效空间尺度。2)景观配置变量(如最大斑块指数、斑块密度等)对水质的影响程度大于景观组成变量(如面积比例和均匀度指数等)。3)景观类型对水质的影响机制具有较大的差异性,农业用地受流域的地形地貌和耕作方式等因素的影响,在100～500 m小尺度的湖滨带缓冲区内对水质退化起主导作用;在远离水体的相对较大尺度(1000～5000 m),林地分布越密集、面积越大,对污染物进入水体的净化作用越明显;草地对水质的影响与林地一致;密集分布的城市用地对水质的影响与林地相反。研究结果可以从宏观尺度上为农业主产区湖泊流域水质管理和景观合理配置提供科学参考。     

幽门螺杆菌感染与胃癌相关基因的筛选及预后分析

目的通过分析幽门螺杆菌感染胃黏膜组织和胃癌细胞系后的差异基因变化,并在癌症基因组图谱(The Cancer Genome Atlas,TCGA)数据库和肿瘤基因芯片(Oncomine)数据库进行验证,探究幽门螺杆菌导致胃癌发生、发展的分子机制。方法分析基因表达汇编(Gene Expression Omnibus,GEO)数据库幽门螺杆菌感染相关芯片集GSE5081与GSE70394,绘制维恩图查找幽门螺杆菌感染后共同上调的差异基因。对共同上调的差异基因进行功能富集分析。通过TCGA和Oncomine数据库验证差异基因在胃癌中的表达。利用Kaplan-Meier Plotter数据库和GEPIA数据库分析差异基因表达高低与胃癌患者预后是否存在相关性。结果通过差异基因筛选和维恩分析,两个芯片集共有21个共同上调差异基因。GO分析发现共同上调差异基因主要富集在对细菌来源分子的反应、趋化因子CXCR受体结合、中性粒细胞趋化作用等相关的基因功能上;KEGG通路主要富集在癌症通路、TNF信号通路、趋化因子信号通路等。STRING以及PPI数据库分析发现21个基因中PRDM1、IL10、NRP1、BIRC3、GNG13、CXCL1、CXCL2、CXCL3、CXCL8基因存在有网络关系,属于关键枢纽基因。通过TCGA和Oncomine数据库筛选及验证,发现在胃癌组织中NRP1、CXCL1、CXCL8基因明显上调,结果差异有统计学意义(TCGA数据库中,三者P值均小于0.05,Oncomine数据库中,NRP1:t=4.607,P0.01;CXCL1:t=5.854,P0.01;CXCL8:t=5.316,P0.01)。在Kaplan-Meier Plotter数据库(210615-at芯片:P0.01;210510-s-at芯片:P0.01;212298-at芯片:P0.01)以及GEPIA数据库(P0.01)两个数据库中,NRP1的高表达均与胃癌的预后负相关。结论不同的数据库均显示NRP1、CXCL1、CXCL8三个基因与幽门螺杆菌感染相关,同时在胃癌中高表达,并且NRP1的高表达与胃癌的不良预后相关,这些结果为进一步探究幽门螺杆菌导致胃癌发生、发展的分子机制提供了重要基础。     

马铃薯甲虫结节性硬化复合物基因LdTSC1和LdTSC2基因的克隆及功能分析

【目的】通过RNAi技术明确马铃薯甲虫TOR上游的关键信号集成节点及类胰岛素信号通道下游基因结节性硬化复合物TSC1和TSC2的功能。旨在为探明马铃薯甲虫类胰岛素信号转导提供更多理论支持。【方法】在NCBI(美国国家生物技术信息中心)获取马铃薯甲虫LdTSC1/2序列,分别利用多重序列比对和系统发育分析确定该基因的完整性和系统发育关系;采用喂食幼虫dsRNA的方法,观察该基因的调低对马铃薯甲虫幼虫生长发育、糖脂代谢的影响。【结果】克隆得到马铃薯甲虫TSC1编码蛋白的氨基酸序列与鞘翅目白蜡窄吉丁直系同源蛋白的氨基酸序列的自展一致度为100%,聚为一支;TSC2编码蛋白的氨基酸序列与鞘翅目白蜡窄吉丁和赤拟谷盗的同源蛋白氨基酸序列的自展一致度为100%,聚为一支。通过分别喂食2龄幼虫LdTSC1/2的dsRNA能有效降低靶标基因的表达量,幼虫出现体重减轻,化蛹率和羽化率显著下降,葡萄糖的吸收转化效率降低,海藻糖含量升高和甘油三酯均减少。【结论】下调2龄幼虫LdTSC1/2的表达量,导致试虫出现抑制了糖脂代谢、脂肪体减少、体重减轻以及发育延迟;结果表明LdTSC1/2调控了马铃薯甲虫幼虫的糖脂代谢过程,显著影响幼虫化蛹和蜕皮过程。     

Meta‐replication,sampling bias,and multi‐scale model selection: A case study on snow leopard (Panthera uncia) in western China

Replicated multiple scale species distribution models (SDMs) have become increasingly important to identify the correct variables determining species distribution and their influences on ecological responses. This study explores multi‐scale habitat relationships of the snow leopard (Panthera uncia) in two study areas on the Qinghai–Tibetan Plateau of western China. Our primary objectives were to evaluate the degree to which snow leopard habitat relationships, expressed by predictors, scales of response, and magnitude of effects, were consistent across study areas or locally landcape‐specific. We coupled univariate scale optimization and the maximum entropy algorithm to produce multivariate SDMs, inferring the relative suitability for the species by ensembling top performing models. We optimized the SDMs based on average omission rate across the top models and ensembles’ overlap with a simulated reference model. Comparison of SDMs in the two study areas highlighted landscape‐specific responses to limiting factors. These were dependent on the effects of the hydrological network, anthropogenic features, topographic complexity, and the heterogeneity of the landcover patch mosaic. Overall, even accounting for specific local differences, we found general landscape attributes associated with snow leopard ecological requirements, consisting of a positive association with uplands and ridges, aggregated low‐contrast landscapes, and large extents of grassy and herbaceous vegetation. As a means to evaluate the performance of two bias correction methods, we explored their effects on three datasets showing a range of bias intensities. The performance of corrections depends on the bias intensity; however, density kernels offered a reliable correction strategy under all circumstances. This study reveals the multi‐scale response of snow leopards to environmental attributes and confirms the role of meta‐replicated study designs for the identification of spatially varying limiting factors. Furthermore, this study makes important contributions to the ongoing discussion about the best approaches for sampling bias correction.     

丙酮丁醇梭菌(Clostridium acetobutylicum)原生质体融合育种研究

为了提高丙酮丁醇梭菌(Clostridium acetobutylicum)的丁醇耐受能力和培养基总糖产丁醇的转化率,通过原生质体融合的方法,研究了溶菌酶浓度及其作用时间、再生培养基种类、55℃条件下菌体致死时间、不同PEG分子量以及作用时间、Ca^2+和Mg^2+不同的添加量对丙酮丁醇梭菌原生质体制备、融合、再生的影响,得到了一套比较系统的丙酮丁醇梭菌的原生质体融合条件,同时通过气相色谱检测了融合菌的产溶剂能力并计算总糖转化率。结果显示,最终得到的215I菌株的总糖转化率比原始菌株提高了34.7%,产丁醇能力比原始菌株提高了32.2%,并且发现1株融合菌能产生新物质。原生质体融合方法在丙酸丁醇梭菌育种方面有广泛的应用潜力,通过融合得到的菌株为丁醇生产奠定了基础。     

Five candidate biomarkers associated with the diagnosis and prognosis of cervical cancer

Purpose: Cervical cancer (CC) is one of the most general gynecological malignancies and is associated with high morbidity and mortality. We aimed to select candidate genes related to the diagnosis and prognosis of CC.Methods: The mRNA expression profile datasets were downloaded. We also downloaded RNA-sequencing gene expression data and related clinical materials from TCGA, which included 307 CC samples and 3 normal samples. Differentially expressed genes (DEGs) were obtained by R software. GO function analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs were performed in the DAVID dataset. Using machine learning, the optimal diagnostic mRNA biomarkers for CC were identified. We used qRT-PCR and Human Protein Atlas (HPA) database to exhibit the differences in gene and protein levels of candidate genes.Results: A total of 313 DEGs were screened from the microarray expression profile datasets. DNA methyltransferase 1 (DNMT1), Chromatin Assembly Factor 1, subunit B (CHAF1B), Chromatin Assembly Factor 1, subunit A (CHAF1A), MCM2, CDKN2A were identified as optimal diagnostic mRNA biomarkers for CC. Additionally, the GEPIA database showed that the DNMT1, CHAF1B, CHAF1A, MCM2 and CDKN2A were associated with the poor survival of CC patients. HPA database and qRT-PCR confirmed that these genes were highly expressed in CC tissues.Conclusion: The present study identified five DEmRNAs, including DNMT1, CHAF1B, CHAF1A, MCM2 and Kinetochore-related protein 1 (KNTC1), as potential diagnostic and prognostic biomarkers of CC.     

GINS2 was regulated by lncRNA XIST/miR-23a-3p to mediate proliferation and apoptosis in A375 cells

Molecular and Cellular Biochemistry - Melanoma ranks second in aggressive tumors, and the occurrence of metastasis in melanoma results in a persistent drop in the survival rate of patients....     

The role of exosomal microRNAs in central nervous system diseases

Molecular and Cellular Biochemistry - MicroRNAs (miRNA), endogenous non-coding RNAs approximately 22 nucleotides long, regulate gene expression by mediating translational inhibition or mRNA...