噬菌体展示系统表达玉米赤霉烯酮模拟表位肽

拟用pⅧ噬菌体展示系统表达玉米赤霉烯酮(Zearalenone,ZEN)模拟表位肽,并验证其反应原性。通过将含有ZEN模拟表位序列以及肠激酶酶切位点的寡聚核苷酸与经过EcoR I和BamH I双酶切的pC89S4噬菌粒连接,构建表达载体pC89-CZEN。pC89-CZEN转化感受态XL1-Blue得到工程菌pC89-ek-zen,然后用KM13超感染、IPTG诱导表达,纯化后得到展示有玉米赤霉烯酮模拟表位的噬菌体颗粒。对KM13超感染时菌体浓度OD600、IPTG诱导时菌体浓度OD600、IPTG加入量以及诱导表达温度和时间进行优化,以探索最佳表达条件;通过ELISA测定反应原性,对比肠激酶酶切前后模拟表位肽与ZEN抗体的结合效果。结果显示,成功构建了表达载体pC89-CZEN,最优表达条件为KM13超感染时菌体浓度OD600为0.4、IPTG诱导时菌体浓度OD600为0.6以及IPTG加入量为终浓度1.0 mmol/L、诱导表达温度为24℃、时间8 h,酶切后结合效果明显高于酶切前。     

性别和温度对中华秋沙鸭越冬行为的影响

2011年11月至2012年3月,在江西婺源采用瞬时扫描法探讨性别和温度对中华秋沙鸭行为的影响.中华秋沙鸭越冬期的主要行为是取食、休息、游泳和修整.时间分配方面,雌雄中华秋沙鸭仅社会行为[雌:(2.13±1.40)％和雄:(3.24±1.55)％]存在显著性差异(t＝-2.258,df＝34,P＜0.05),其他行为差异不显著(P＞0.05).原因有:(1)非繁殖期雌雄中华秋沙鸭主要任务均为生存;(2)雌雄个体大小差异不大,对能量的需求量相似.日活动节律方面,雌雄的取食和休息行为均存在显著的节律性变化,分别为雌:取食(F(10,165)＝5.19,P＜0.05)、休息(F(10,165)＝ 2.56,P＜0.05)和雄:取食(F(10,165)＝ 7.55,P＜0.05)、休息(F(10,165)＝ 3.48,P＜0.05),其他行为节律均不显著(P＞0.05).温度对中华秋沙鸭越冬行为的影响较大,时间分配方面,在＜10℃月份环境下,取食(t＝-2.166,df＝ 16,P＜0.05)行为显著高于＞10℃月份,而游泳(t＝5.096,df＝ 16,P＜0.05)行为则相反,其他行为差异不显著(P＞0.05).这一结果表明,平均温度降低时,中华秋沙鸭需要摄取更多的食物以补充寒冷天气能量的消耗,并减少游泳行为降低耗能.日活动节律方面,＞10℃月份中华秋沙鸭日活动节律,仅警戒(F(10,77)＝1.96,P＜0.05)行为存在显著的节律性变化,其他行为的节律性变化不显著(P＞0.05).＜10℃月份中华秋沙鸭取食(F(10,86)＝ 5.93,P＜0.05)和休息( F(10,86)＝ 3.42,P＜0.05)行为存在显著的节律性变化,其他行为的节律性变化不显著(P＞0.05).研究结果表明,温度可以改变中华秋沙鸭的日活动节律,低温使中华秋沙鸭在夜间消耗较多能量,因此中华秋沙鸭在上午花更多的时间取食来补充能量.休息行为在＞10℃月份,中午和傍晚均有一个小的高峰,而在＜10℃月份从11:00开始(除13:00-13:59)均保持较高的水平.中华秋沙鸭采取这种对策,可能是＜10℃月份,晚上和下午温度较低,为了减少消耗,从下午就开始增加休息行为.低温条件下,中华秋沙鸭增加修整和休息行为,这一结果支持“鸟类在低温环境下通过减少行为活动以降低能量消耗和热量损失”这一观点.     

Knockdown of UCA1 attenuated the progression of alcoholic fatty disease by sponging miR-214

Alcoholic fatty liver (AFL) is the initial manifestation of Alcoholic liver disease which can develop into alcoholic cirrhosis even extensive necrosis of liver cells, which induces liver failure finally. This study aims to focus on the role of long noncoding RNA UCA1 in AFL and further explored possible mechanism of this disease. We first downloaded GSE28619 to identify the expression of UCA1 in patients with AFL and use lncRNAs microarray to confirm UCA1 expression in serum of patients with AFL. Then we established ethanol-induced L02 cell model to mimic hepatocyte injury condition. By conducting qRT-PCR, we measured the expression of LncRNA UCA1 and miR-214 in serum of patients and ethanol-induced L02 cell. MTT assay, transwell migration, ELISA, qRT-PCR, and western blotting analysis were applied to evaluating the effect of UCA1 on ethanol-induced L02 cell. The bioinformatics analysis and the rescue experiment were devoted to the underlying mechanism. In this study, we first detected the expression of UCA1 was up-regulated in serum of patients with AFL and ethanol-induced L02 cells. And knockdown of UCA1 reversed the inhibiting effect of ethanol on the biological behavior of L02 cells including cell proliferation, migration, and apoptosis. Besides, lncRNA UCA1 regulated the expression of KLF5 by sponging miR-214. LncRNA UCA1 regulated the biological behavior of ethanol-induced L02 cells by sponging miR-214, which may provide novel therapeutic strategies for alcoholic fatty liver.

     

中国红豆属植物生物与生态学特征研究现状

红豆属(Ormosia)隶属豆科(Fabaceae),全属约130种,均为木本植物,我国有37种,广东、广西、云南、海南为主要分布区。该属野外自然更新能力较差,对生存环境要求严格。由于该属大部分物种具有极高的经济价值和开发利用价值,因此人为干扰及盗伐现象严重,分布范围收缩且野外种群数量减少。本文在查阅文献的基础上,对红豆属植物的生态学特征、组织培养、生理生化、遗传、濒危现状与保护对策等方面的研究成果进行归纳总结并进行了展望,以期为深入研究红豆属植物、拯救红豆属物种提供参考。     

亚热带杉木（Cunninghamia lanceolata）人工林生长与土壤养分对氮沉降的响应

为探讨亚热带森林对氮沉降增加的响应,项目在杉木人工林中开展了野外模拟N沉降试验,分N0(对照)、N1、N2、N3等4种处理,N沉降量分别为0、60、120、240(kgNhm-2a-1)。通过3a的研究发现,中高氮处理(N2、N3)明显促进了杉木胸径的生长,而低氮处理(N1)则没有产生明显影响。氮沉降对树高生长也有明显的促进作用,但随着氮沉降水平的增加其影响有减弱趋势。通过各水平N处理后,杉木年平均蓄积增长量分别为28.82、28.96、32.63m3hm-2和33.68m3hm-2,表明N沉降在一定程度上增加了林分蓄积量的积累,但处理之间的差异没有达到统计上的显著性水平。随着氮沉降水平的增加,NH4 -N和NO3--N含量明显上升,而土壤pH值、有机质、速效P、速效K和交换性Ca、Mg含量则呈下降趋势。杉木针叶养分状况对氮沉降的响应也比较敏感,N1、N2、N3处理使针叶平均N含量分别增加18.25%、11.68%和13.14%,但对P、K、Ca、Mg含量表现出一定的抑制作用。     

Possible mechanism of flicking-induced short-term plasticity in retinal cone-LHC synapse: a computational study

In retinal cone-HC synapse, it has been found that repetitive stimulation could induce postsynaptic short-term responsiveness enhancement. However, the detailed mechanism underlying this short-term plasticity in the retinal graded neurons remains unclear. In this study, based on an ion-channel model described using Hodgkin--Huxley equations, the possible mechanism of repetitive-stimulation-induced short-term plasticity in the synapse between retinal cones and horizontal cells was investigated. The computational simulation results, together with evidence from experimental observations, suggest that the short-term modification of signal transmission between the retinal graded neurons is likely to be attributed to the regulatory effects that calcium-dependent process exerts on the single-channel properties of the postsynaptic AMPA receptors.     

插壤温度对四倍体刺槐硬枝插条生根过程中生理生化的影响

取四倍体刺槐3年生采穗圃中1年生硬枝插条为材料,研究扦插过程中插壤温度对插穗内源激素含量、酶活性和营养物质含量的影响,揭示四倍体刺槐扦插生根机制。结果表明：四倍体刺槐硬枝扦插过程中,插壤经加热处理,插穗内源IAA含量降低,ABA和ZR含量升高;根原基诱导期插穗内源IAA含量的变化趋势与未加热插穗相反,ABA和ZR含量的变化趋势与未加热插穗相同。插壤经加热处理,插穗IAAO、PPO和POD活性的变化趋势与未加热插穗相同,两处理间插穗IAAO、PPO和POD活性差异不显著。插壤经加热处理,可显著提高插穗可溶性蛋白和可溶性糖含量,而对淀粉和植物总氮含量的影响差异不显著。因此,插壤加热处理,主要是通过降低四倍体刺槐硬枝插穗内源IAA含量,提高插穗可溶性蛋白和可溶性糖含量来促进插条不定根发生。     

井冈山自然保护区12种常见灌木生物量的估测模型

灌木生物量模型是估测灌木生物量的重要方法之一。以井冈山自然保护区林下12种常见灌木为研究对象,根据树高（H）和地径（D）两个形态因子作为变量,进行回归分析构建模型。通过对比判别系数R 2的大小,筛选最佳生物量估测模型。方程W=a＋b X12 X2、W=a＋b X＋c X 2和W=a X b在模拟生物量时相关指数均较高,为0.904-0.991,达到极显著水平,可用于实际生物量估测,而方程W=a＋b X、W=a＋b X1＋c X2和W=a＋b ln X在模拟灌木生物量时结果较差。利用此类方法建立的生物量模型,精度高,简便易行,对以后估算井冈山自然保护区灌木生物量和碳储量具有十分重要的意义。     

Consensus methods based on machine learning techniques for marine phytoplankton presence–absence prediction

We performed different consensus methods by combining binary classifiers, mostly machine learning classifiers, with the aim to test their capability as predictive tools for the presence–absence of marine phytoplankton species. The consensus methods were constructed by considering a combination of four methods (i.e., generalized linear models, random forests, boosting and support vector machines). Six different consensus methods were analyzed by taking into account six different ways of combining single-model predictions. Some of these methods are presented here for the first time. To evaluate the performance of the models, we considered eight phytoplankton species presence–absence data sets and data related to environmental variables. Some of the analyzed species are toxic, whereas others provoke water discoloration, which can cause alarm in the population. Besides the phytoplankton data sets, we tested the models on 10 well-known open access data sets. We evaluated the models' performances over a test sample. For most (72%) of the data sets, a consensus method was the method with the lowest classification error. In particular, a consensus method that weighted single-model predictions in accordance with single-model performances (weighted average prediction error — WA-PE model) was the one that presented the lowest classification error most of the time. For the phytoplankton species, the errors of the WA-PE model were between 10% for the species Akashiwo sanguinea and 38% for Dinophysis acuminata. This study provides novel approaches to improve the prediction accuracy in species distribution studies and, in particular, in those concerning marine phytoplankton species.