Responses of the distribution of four epiphytic cyanolichens to habitat changes in subtropical forests

 蓝藻地衣是附生植物类群的重要组成部分, 在森林生态系统的环境监测和养分循环中发挥着重要作用。该研究在云南哀牢山亚热带森林系统的2种原生和6种次生森林群落中, 以粉缘绵毛衣(Leioderma sorediatum)、天蓝猫耳衣(Leptogium azureum)、网肺衣(Lobaria retigera)和双缘牛皮叶(Sticta duplolimbata) 4种常见蓝藻地衣为对象, 共设立120个样地, 调查了它们在3 600株树木0–2 m树干上的分布, 探讨其分布特征及与森林类群、宿主种类以及林龄等生境因子的关系。研究发现4种蓝藻地衣在森林群落间的分布模式明显不同。除双缘牛皮叶的盖度和频度在原生苔藓矮林中最高外, 其他3种蓝藻地衣的最高值均出现于次生林如厚皮香(Ternstroemia gymnanthera)林和滇山杨(Populus bonatii)林中; 而哀牢山地区广布的原生木果柯(Lithocarpus xylocarpus)林中, 4种蓝藻地衣极为少见。4种地衣都能生长于10多个树种上, 但明显表现出对厚皮香、滇山杨和硬壳柯(Lithocarpus hancei)等树种的偏好性, 以及对小花山茶(Camellia forrestii)等的排斥性。森林群落的林龄、胸径、最大胸径、林冠开阔度、基面积、树木密度和树种多样性等因子的变化均对4种附生蓝藻地衣的分布产生重要影响, 但在景观尺度上影响程度相对较小, 在不同森林群落内部却有各自的重要作用。其中, 林龄、林冠开阔度和宿主胸径是影响蓝藻地衣分布的最重要的生境因子。     

Effects of Mathematics Anxiety and Mathematical Metacognition on Word Problem Solving in Children with and without Mathematical Learning Difficulties

Mathematics is one of the most objective, logical, and practical academic disciplines. Yet, in addition to cognitive skills, mathematical problem solving also involves affective factors. In the current study, we first investigated effects of mathematics anxiety (MA) and mathematical metacognition on word problem solving (WPS). We tested 224 children (116 boys, M = 10.15 years old, SD = 0.56) with the Mathematics Anxiety Scale for Children, the Chinese Revised-edition Questionnaire of Pupil’s Metacognitive Ability in Mathematics, and WPS tasks. The results indicated that mathematical metacognition mediated the effect of MA on WPS after controlling for IQ. Second, we divided the children into four mathematics achievement groups including high achieving (HA), typical achieving (TA), low achieving (LA), and mathematical learning difficulty (MLD). Because mathematical metacognition and MA predicted mathematics achievement, we compared group differences in metacognition and MA with IQ partialled out. The results showed that children with MLD scored lower in self-image and higher in learning mathematics anxiety (LMA) than the TA and HA children, but not in mathematical evaluation anxiety (MEA). MLD children’s LMA was also higher than that of their LA counterparts. These results provide insight into factors that may mediate poor WPS performance which emerges under pressure in mathematics. These results also suggest that the anxiety during learning mathematics should be taken into account in mathematical learning difficulty interventions.     

Multicolor Melting Curve Analysis-Based Multilocus Melt Typing of Vibrio parahaemolyticus

Vibrio parahaemolyticus is the leading cause of seafood-borne gastroenteritis outbreaks. To track the source of these diseases in a timely manner, a high throughput typing method is critical. We hereby describe a novel genotyping method for V. parahaemolyticus, termed multilocus melt typing (MLMT), based on multilocus sequence typing (MLST). MLMT utilizes melting curve analysis to interrogate the allelic types of a set of informative single nucleotide polymorphisms (SNPs) derived from the housekeeping genes used in MLST. For each SNP, one allelic type generates distinct T_m values, which are converted into a binary code. Multiple SNPs thus generate a series of binary codes, forming a melt type (MT) corresponding with a sequence type (ST) of MLST. Using a set of 12 SNPs, the MLMT scheme could resolve 218 V.parahaemolyticus isolates into 50 MTs corresponding with 56 STs. The discriminatory power of MLMT and MLST was similar with Simpson’s index of diversity of 0.638 and 0.646, respectively. The global (adjusted Rand index = 0.982) and directional congruence (adjusted Wallace coefficient, MT→ST = 0.965; ST→MT = 1.000) between the two typing approaches was high. The entire procedure of MLMT could be finished within 3 h with negligible hands on time in a real-time PCR machine. We conclude that MLMT provides a reliable and efficient approach for V. parahaemolyticus genotyping and might also find use in other pathogens.     

MiR-27靶基因的分析及鉴定

MicroRNAs(miRNAs)是一类约20～25nt的小分子核苷酸,在细胞内的多种生物学过程,如细胞增殖、凋亡、生长、分化和代谢等过程中具有重要的功能。已知miR-27在脂肪细胞和肌肉细胞的发育过程中起了重要作用,其在神经细胞中的表达调节至今仍不清楚。在本研究中,通过miRBase和TargetScan数据库分析了miR-27的靶基因,构建了miR-27的真核表达载体,改造了萤火虫荧光素酶和海肾荧光素酶报告载体,将miR-27的靶基因Bmi1的3′-UTR融合到报告载体中,转染神经胶质瘤细胞,利用双荧光素酶检测系统分析荧光素酶的活性。研究发现miR-27a和miR-27b共同的靶基因主要调节发育过程。MiR-27真核表达载体能产生成熟态的miR-27。MiR-27a、miR-27b或miR-27a和miR-27b联合与Bmi1的3′-UTR的正义序列共转染U343细胞能明显降低萤火虫荧光素酶的活性(分别P0.05,P0.05,P0.01),这提示了Bmi1可能为miR-27的靶基因。     

流速对红鳍银鲫幼鱼游泳状态的影响

在28℃水温下,采用特制的鱼类游泳行为测定装置,研究体重(125.94±13.87)g的红鳍银鲫(Barbodes schwanenfeldi)幼鱼在0.0m/s(对照组)和0.1m/s、0.3m/s、0.5m/s3种流速下的游泳行为。结果表明,从0.0～0.3m/s,红鳍银鲫幼鱼平均趋流率和摆尾频率均随着流速的增加而增大,而0.5m/s组在90min内随时间延长而下降。红鳍银鲫游泳状态明显受到所处流速的影响,在静水对照组以"逆流前进"和"顺流而下"为主,两者共占总观察时间的98%以上;各流速组均以逆流静止为主,且随着流速的增大,逆流静止所占时间比例从45.8%增加至81.3%,而逆流前进所占时间比例由24.1%减至5%以下;逆流后退所占时间比例以0.1m/s组最大,为16.4%;顺流而下的比例随着流速增大先减小后增大,3个流速组依次为13.7%、2.1%和10.9%。红鳍银鲫幼鱼的游泳速度(V)和摆尾频率(TBF)在逆流前进及逆流静止两种游泳状态下呈线性正相关,而在逆流后退和顺流而下两种状态下两者没有显著相关。     

西双版纳区域气候变化对植物生长趋势的影响

目前全球变暖已经致使地球上生物群系的格局发生了显著的变化。高纬度地区的植物生长由此变得更加活跃,而热带地区植物生长的趋势仍然是一个具有争论的问题。西双版纳热带植物园地处中国西南地区,20世纪70年代以来,这里气候发生了显著的变化,其气温以每10年0.18℃的速度上升。本研究利用西双版纳热带植物园中的48种热带植物（28科）的株高生长数据（1974～2003年）来分析其对西双版纳区域气候变化的长期变化响应,通过对株高与气候因子的相关分析选出对植物株高生长影响最大的气候因子。结果表明,植物在研究期间的株高生长年间波动比较强烈,但没有表现出明显的趋势;植物的株高生长主要受到干热季（3、4月份）的日照时数（负）与月均最低气温（正）所影响,而干热季正是这些植物每年开始萌叶的时期;另外,降雨并没有对引种植物株高生长产生显著的影响;从2个关键因子的长期变化趋势来看,西双版纳气候变化将有利于保护植物的生长,进而将有利于植物园内热带植物的保护与保存。     

番茄和桃基因组的微同线性研究

番茄和桃是茄科和蔷薇科的重要模式植物.近年来, 随着它们基因组测序工作的展开, 相关基因组序列快速累积, 为番茄和桃遗传图谱和物理图谱的比较分析及深入了解其进化关系提供了可能.文章对番茄和桃的基因组进行了比较, 通过番茄遗传图谱与桃物理图谱、番茄物理图谱与桃遗传图谱以及番茄物理图谱与桃物理图谱等3个层面的数据比对分析, 结果揭示在这两个基因组间存在着大量的微同线性片段.这些同线性片段中所包含的保守同源基因对的数目较少(总计297个同线性片段中仅有36个片段包含有两个以上的同源基因对).这些同线性片段都是小范围的, 并且有部分微同线性片段在不同的染色体或者BAC contig之间构成了一个相互关联的网络结构.通过与番茄的EST文库比对, 发现了9个与果实发育和成熟相关的微同线性基因.这些微同线性基因的发现对于进一步研究这两个亲缘关系比较远的物种在果实发育与成熟方面的共性提供了线索.     

Two New Diophrys‐Like Genera and Their Type Species,Apodiophrys ovalis n. g., n. sp. and Heterodiophrys zhui n. g., n. sp. (Ciliophora: Euplotida), with Notes on Their Molecular Phylogeny

ABSTRACT. Based on both morphological and molecular information, two new euplotid genera Apodiophrys n. g. and Heterodiophrys n. g. are described in the present paper. Apodiophrys n. g. is defined as sculptured Diophryinae with bipartite adoral zone; frontoventral cirri arranged in Diophrys‐pattern; marginal cirri located in two clearly separated groups. Heterodiophrys n. g. is recognizable by the combination of Diophrys‐like frontoventral cirri and the unique structure of several marginal cirri that are arranged in a long row. The type species for both new genera, Apodiophrys ovalis n. sp. and Heterodiophrys zhui n. sp., collected from southern China sea, are described. The small subunit rRNA (SSU rRNA) gene sequences for both new taxa are determined. Phylogenetic analyses based on these data indicate that Apodiophrys is most closely related to Paradiophrys, which then clusters with Uronychia species. Thus, Apodiophrys–Paradiophrys is separated from other typical Diophrys‐like genera in the SSU rRNA gene trees. The new genus Heterodiophrys is basal to the sister group of Diophrys–Diophryopsis, hence belongs to the “core”Diophrys‐complex.     

嵌合内含子对抗bFGF抗体基因在293T细胞中表达的影响

目的：构建含嵌合内含子和抗bFGF抗体基因的真核表达载体并在293T细胞中表达,探讨嵌合内含子对抗体表达的影响。方法：设计引物分别从载体pCl-neo和pComb3-Fab25中扩增出内含子和抗体Fd段、κ链基因序列,按不同组合构建到含人免疫球蛋白IgG1恒定区Fc段基因的表达载体pIgG中。重组质粒经脂质体PEI转染293T细胞,荧光显微镜观察质粒转染情况,采用夹心ELISA和Western blot检测细胞上清中抗体的表达。结果：DNA测序和酶切分析表明,内含子和抗体基因成功插入pIgG,获得了重组质粒pIgG-Fd-κ、pIgG-Fd-intron-κ、pIgG-Fd-κ-intron和pIgG-Fd-intron-κ-intron。倒置荧光显微镜下可观察EGFP大量表达,Western blot分析上清中有抗体的表达,夹心ELISA检测pIgG-Fd-κ、pIgG-Fd-intron-κ、pIgG-Fd-κ-intron和pIgG-Fd-intron-κ-intron抗体表达量分别为1.21mg/L、0.468mg/L、7.39mg/L、0.601mg/L。结论：成功构建了含嵌合内含子和抗体基因的真核表达载体并在293T细胞中得到表达。嵌合内含子插入κ链基因5’端可提高抗体的表达,插入Fd段5’端则抑制抗体的表达。     

一种基于PCR技术鉴定单拷贝转基因烟草的方法

为了鉴定携带单拷贝外源基因的转基因烟草植株,以烟草核基因组上已知的单拷贝内源基因（RNR2）为内参,转基因烟草植株基因组DNA为模板,在同一PCR反应体系中扩增内源基因（RNR2）和外源目的基因（NPTⅡ）。反应产物在琼脂糖凝胶上电泳,获得了预期大小的两条特异性扩增条带。经ImageJ软件捕捉分析两条目的条带的灰度比,当T1代转基因烟草植株中外源基因与内源基因的扩增条带灰度比为1时,所检测植株即为单拷贝外源基因的转基因烟草植株。孟德尔经典遗传学方法证实了上述检测结果高度可信。