合理化防的马尾松林动物和虫生真菌群落的数量时空格局

对马尾松纯林中动物和虫生真菌群落的调查表明 ,植食性、捕食性、寄生性昆虫和蜘蛛类群物种数分别占 51 %、1 2 %、7%和 2 6% ,益害生物个体数之比约 1∶ 1 0 .2个相似的林分或林间层次中 ,物种数、科数相等或相近 ,优势目相同 ,而且二者的植食性、捕食性、寄生性昆虫和蜘蛛类群的物种数和个体数的波动相对应地趋于一致 .主成分分析显示群落 1周年内处于“深秋准备越冬→冬眠→早春复苏→春、夏、初秋繁荣”的循环演替之中 ,其自我调节力和稳定性较强     

High-fat diet-induced lipidome perturbations in the cortex,hippocampus, hypothalamus,and olfactory bulb of mice

Given their important role in neuronal function, there has been an increasing focus on altered lipid levels in brain disorders. The effect of a high-fat (HF) diet on the lipid profiles of the cortex, hippocampus, hypothalamus, and olfactory bulb of the mouse brain was investigated using nanoflow ultrahigh pressure liquid chromatography-electrospray ionization-tandem mass spectrometry in the current study. For 8?weeks, two groups of 5-week-old mice were fed either an HF or normal diet (6 mice from each group analyzed as the F and N groups, respectively). The remaining mice in both groups then received a 4-week normal diet. Each group was then subdivided into two groups for another 4-week HF or normal diet. Quantitative analysis of 270 of the 359 lipids identified from brain tissue revealed that an HF diet significantly affected the brain lipidome in all brain regions that were analyzed. The HF diet significantly increased diacylglycerols, which play a role in insulin resistance in all regions that were analyzed. Although the HF diet increased most lipid species, the majority of phosphatidylserine species were decreased, while lysophosphatidylserine species, with the same acyl chain, were substantially increased. This result can be attributed to increased oxidative stress due to the HF diet. Further, weight-cycling (yo-yo effect) was found more critical for the perturbation of brain lipid profiles than weight gain without a preliminary experience of an HF diet. The present study reveals systematic alterations in brain lipid levels upon HF diet analyzed either by lipid class and molecular levels.     

Cytokinin‐dependent specification of the functional megaspore in the Arabidopsis female gametophyte

The life cycle of higher plants alternates between the diploid sporophytic and the haploid gametophytic phases. In angiosperms, male and female gametophytes develop within the sporophyte. During female gametophyte (FG) development, a single archesporial cell enlarges and differentiates into a megaspore mother cell, which then undergoes meiosis to give rise to four megaspores. In most species of higher plants, including Arabidopsis thaliana, the megaspore closest to the chalaza develops into the functional megaspore (FM), and the remaining three megaspores degenerate. Here, we examined the role of cytokinin signaling in FG development. We characterized the FG phenotype in three triple mutants harboring non‐overlapping T–DNA insertions in cytokinin AHK receptors. We demonstrate that even the strongest mutant is not a complete null for the cytokinin receptors. Only the strongest mutant displayed a near fully penetrant disruption of FG development, and the weakest triple ahk mutant had only a modest FG phenotype. This suggests that cytokinin signaling is essential for FG development, but that only a low threshold of signaling activity is required for this function. Furthermore, we demonstrate that there is elevated cytokinin signaling localized in the chalaza of the ovule, which is enhanced by the asymmetric localization of cytokinin biosynthetic machinery and receptors. We show that an FM‐specific marker is absent in the multiple ahk ovules, suggesting that disruption of cytokinin signaling elements in Arabidopsis blocks the FM specification. Together, this study reveals a chalazal‐localized sporophytic cytokinin signal that plays an important role in FM specification in FG development.     

Morphological and genetic relationship of two closely‐related giant water bugs: Appasus japonicus Vuillefroy and Appasus major Esaki (Heteroptera: Belostomatidae)

The East Asian giant water bug species Appasus japonicus Vuillefroy and Appasus major Esaki are aquatic hemipteran insects whose ranges overlap, particularly in the Japanese Archipelago and on the Korean Peninsula. In rare cases, the two species co‐occur. Furthermore, they are very similar ecologically and also morphologically, making their identification extremely difficult, and the possibility of hybridization has also been suggested. In the present study, we re‐examined their taxonomic validity, and the characteristics useful for identifying them. To re‐examine the morphological traits useful for distinguishing these two species, 222 specimens of A. japonicus collected from Japan, Korea, and China, and 132 specimens of A. major from Japan and Korea, were examined. We also performed molecular phylogenetic analyses based on the mitochondrial DNA 16S rRNA and cytochrome oxidase subunit I (COI) regions and the nuclear DNA Histone 3 region. Although the two species are very similar ecologically and also morphologically, they showed significant genetic differentiation. Thus, there is likely some form of reproductive isolation acting between them. Major morphological characteristics overlap extensively between A. japonicus and A. major, and no particular trait was identified as being effective for differentiating these species. All the morphological characteristics examined overlapped between A. japonicus and A. major. However, a principal component analysis based on all of the morphological characteristics revealed that, despite the overlap between these species, it was possible to morphologically distinguish them. Therefore, a more accurate identification becomes possible using multiple characteristics rather than a single characteristic. The male genital paralobes, evaluated as the most useful morphological characteristic, was effective with 100% probability for the Japanese Appasus species. However, for the Asian (i.e. Korean) specimens, this characteristic was not useful. On the other hand, the results of molecular phylogenetic analyses based on the mitochondrial DNA 16S rRNA and COI regions and the nuclear DNA Histone 3 region clearly showed significant genetic differentiation between the two species. Notably, the results for the mitochondrial COI region strongly supported the independence of each monophyletic group (i.e. validity of each species). Therefore, DNA barcoding based on the mitochondrial DNA COI region is also considered useful for the identification of A. japonicus and A. major. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110 , 615–643.     

New Effective Method for Analysis of the Component Composition of Enzyme Complexes from <Emphasis Type="Italic">Trichoderma reesei</Emphasis>

A method for analysis of the component composition of multienzyme complexes secreted by the filamentous fungus Trichoderma reesei was developed. The method is based on chromatofocusing followed by further identification of protein fractions according to their substrate specificity and molecular characteristics of the proteins. The method allows identifying practically all known cellulases and hemicellulases of T. reesei: endoglucanase I (EG I), EG II, EG III, cellobiohydrolase I (CBH I), CBH II, xylanase I (XYL I), XYL II, beta-xylosidase, alpha-L-arabinofuranosidase, acetyl xylan esterase, mannanase, alpha-galactosidase, xyloglucanase, polygalacturonase, and exo-beta-1,3-glucosidase. The component composition of several laboratory and commercial T. reesei preparations was studied and the content of the individual enzymes in these preparations was quantified. The influence of fermentation conditions on the component composition of secreted enzyme complexes was revealed. The characteristic features of enzyme preparations obtained in "cellulase" and "xylanase" fermentation conditions are shown.     

Observations on 6-mercaptopurine activity in Saccharomyces cerevisiae

Abstract Hydrogen fluoride treatment of [¹⁴C-glycerol]lipoteichoic acid synthesized by growing Streptococcus faecium ATCC9790 in the presence of 1,3[¹⁴C]glycerol produced five radioactive, water-soluble products which were identified by chromatographic and analytical techniques to be tetraglucosyl glycerol, triglucosyl glycerol, diglucosyl glycerol, monoglucosyl glycerol and unsubstituted glycerol. The percent composition of each varied modestly from culture to culture and ranged between 7 and 8% for the tetra-, 20.5 and 31.2% for the tri-, 11.3 to 23.5% for the di-, 20.9 to 26.8% for the mono-, and 23.1 to 34.8% for the unsubstituted glycerol. The same glucosylated glycerol compounds could be obtained in an in vitro reaction in which a 30 000 × g particulate enzyme catalyzed the incorporation of [³H]glucose from UDP [³H]glucose into lipoteichoic acid.     

空间独立成分分析实现fMRI信号的盲分离

独立成分分析（ICA）在功能核磁共振成像（fMRI)技术中的应用是近年来人们关注的一个热点。简要介绍了空间独立成分分析（SICA）的模型和方法,将fMRI信号分析看作是一种盲源分离问题,用快速算法实现fMRI信号的盲源分离。对fMRI信号的研究大多是在假定已知事件相关时间过程曲线的情况下,利用相关性分析得到脑的激活区域。在不清楚有哪几种因素对fMRI信号有贡献、也不清楚其时间过程曲线的情况下,用SICA可以对fMRI信号进行盲源分离,提取不同独立成分得到任务相关成分、头动成分、瞬时任务相关成分、噪声干扰、以及其它产生fMRI信号的多种源信号。     

The genetic component of human longevity: New insights from the analysis of pathway‐based SNP‐SNP interactions

In human longevity studies, single nucleotide polymorphism (SNP) analysis identified a large number of genetic variants with small effects, yet not easily replicable in different populations. New insights may come from the combined analysis of different SNPs, especially when grouped by metabolic pathway. We applied this approach to study the joint effect on longevity of SNPs belonging to three candidate pathways, the insulin/insulin‐like growth factor signalling (IIS), DNA repair and pro/antioxidant. We analysed data from 1,058 tagging SNPs in 140 genes, collected in 1825 subjects (1,089 unrelated nonagenarians from the Danish 1905 Birth Cohort Study and 736 Danish controls aged 46–55 years) for evaluating synergic interactions by SNPsyn. Synergies were further tested by the multidimensional reduction (MDR) approach, both intra‐ and interpathways. The best combinations (FDR<0.0001) resulted those encompassing IGF1R‐rs12437963 and PTPN1‐rs6067484, TP53‐rs2078486 and ERCC2‐rs50871, TXNRD1‐rs17202060 and TP53‐rs2078486, the latter two supporting a central role of TP53 in mediating the concerted activation of the DNA repair and pro‐antioxidant pathways in human longevity. Results were consistently replicated with both approaches, as well as a significant effect on longevity was found for the GHSR gene, which also interacts with partners belonging to both IIS and DNA repair pathways (PAPPA, PTPN1, PARK7, MRE11A). The combination GHSR‐MREA11, positively associated with longevity by MDR, was further found influencing longitudinal survival in nonagenarian females (p = .026). Results here presented highlight the validity of SNP‐SNP interactions analyses for investigating the genetics of human longevity, confirming previously identified markers but also pointing to novel genes as central nodes of additional networks involved in human longevity.     

坡度对农田土壤动物群落结构及多样性的影响

为了研究坡度对土壤动物群落的影响,于2010年3月和9月分别对川中丘陵区坡度为5°、15°、25°的3种农田土壤动物进行了调查。共采集土壤动物11657只,隶属4门11纲21目,弹尾目、蜱螨目、颤蚓目和线虫为优势类群。土壤动物群落的类群数在3月随坡度增加无显著变化(P>0.05),9月则呈波动性上升(P<0.01)。群落密度在3月随坡度增加而显著下降(P<0.01),9月的变化趋势则相反(P<0.05)。群落多样性指数在3、9两月均随坡度增加呈显著波动性变化(P<0.05)。坡度对弹尾目、蜱螨目和线虫等主要类群的密度影响显著(P<0.05),并具季节差异。主成分分析(PCA)结果表明坡度对农田土壤动物的群落结构有明显影响,Sorenson和Morisita-Horn相似性系数进一步表明坡度在3月份主要影响土壤动物群落的类群组成,在9月主要影响优势类群的密度。研究结果表明坡度对土壤动物的群落结构、多样性及主要类群的密度有显著影响,并存在季节差异。     

Bias of maximum likelihood estimator of intraclass correlation

Summary A bias correction was derived for the maximum likelihood estimator (MLE) of the intraclass correlation. The bias consisted of two parts: a correction from MLE to the analysis of variance estimator (ANOVA) and the bias of ANOVA. The total possible bias was always negative and depended upon both the degree of correlation and the design size and balance. The first part of the bias was an exact algebraic expression from MLE to ANOVA, and the corrected estimator by this part was ANOVA. It was also shown that the first correction term was equivalent to Fisher's reciprocal bias correction on hisZ scores. The total possible bias of MLE was large for small and moderate samples. Relative biases were larger for small parametric values and vice versa. To ensure a relative bias less than 10% assuming an intraclass correlation of 0.025, which is not unusual in most of the animal genetic studies, the total number of observations (N) should be not less than 500. From a design point of view, minimum bias occurred atn = 2, the minimum family size possible, underN fixed.