An investigation of the dynamics of spermine bound to duplex and quadruplex DNA by <Superscript>13</Superscript>C NMR spectroscopy

A detailed analysis of the ¹³C relaxation of ¹³C-labelled spermine bound to duplex and quadruplex DNA is presented. T₁, T₂ and heteronuclear NOE data were collected at four ¹³C frequencies (75.4, 125.7, 150.9 and 201.2 MHz). The data were analyzed in terms of a frequency-dependent order parameter, S ²(ω), to estimate the generalized order parameter and the contributions to the relaxation from different motional frequencies in the picosecond–nanosecond timescale and from any exchange processes that may be occurring on the microsecond–millisecond timescale. The relaxation data was surprisingly similar for spermine bound to two different duplexes and a linear parallel quadruplex. Analysis of the relaxation data from these complexes confirmed the conclusions of previous studies that the dominant motion of spermine is independent of the macroscopic tumbling of the DNA and has an effective correlation time of ∼50 ps. In contrast, spermine bound to a folded antiparallel quadruplex had faster relaxation rates, especially R ₂. As with the other complexes, a fast internal motion of the order of 50 ps makes a substantial contribution to the relaxation. The generalized order parameter for spermine bound to duplex DNA and the linear quadruplex is small but is larger for spermine bound to the folded quadruplex. In the latter case, there is evidence for exchange between at least two populations of spermine occurring on the microsecond–millisecond timescale. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effect of Maternal Ethanol Consumption during Pregnancy and Lactation on Kinetic Parameters of Folic Acid Intestinal Transport in Suckling Rats

Ethanol ingestion is known to interfere with folate absorption and metabolism. A fostering/crossfostering analysis of maternal ethanol exposure effects on jejunum and ileum kinetic parameters in vivo of offspring rat folic acid absorption at 21 days postpartum was carried out. The rats were divided into four groups: CP, control pups; GP, pups exposed to ethanol only during gestation; LP, pups exposed to ethanol only during lactation; GLP, pups exposed to ethanol during gestation and lactation. Jejunal and ileal loop transport studies were performed using in vivo perfusion at a flow rate of 3 ml/min for 5 min. Folic acid concentrations of 0.25, 0.5, 1, 1.5 and 2.5 μm were used. Jejunal and ileal absorption values were determined by the difference between the initial and the final amounts of substrate in the perfusate and expressed as picomoles per square centimeter of intestinal surface every 5 min. The results indicated that ethanol consumption by the dams during gestation and/or lactation led to significant changes in V _max, with no significant changes in apparent K _m. These findings suggest that exposure to ethanol during gestational and suckling periods leads to a general delay in postnatal body weight and that intestinal folate absorption appears to be upregulated in suckling rats, this effect being higher in the LP group.     

Exact one-sided confidence bounds for the risk ratio in 2 x 2 tables with structural zero

This paper examines exact one-sided confidence limits for the risk ratio in a 2 x 2 table with structural zero. Starting with four approximate lower and upper limits, we adjust each using the algorithm of Buehler (1957) to arrive at lower (upper) limits that have exact coverage properties and are as large (small) as possible subject to coverage, as well as an ordering, constraint. Different Buehler limits are compared by their mean size, since all are exact in their coverage. Buehler limits based on the signed root likelihood ratio statistic are found to have the best performance and recommended for practical use.     

Probing the dynamics of intact cells and nuclear envelope precursor membrane vesicles by deuterium solid state NMR spectroscopy

Membrane dynamics is an essential part of many cellular mechanisms such as intracellular trafficking, membrane fusion/fission and mitotic organelle reconstitution. The dynamics of membranes is dependent primarily on their phospholipid and cholesterol composition and how these molecules are ordered in relation to one another. To determine the physical status of membranes in whole cells or purified membranes of subcellular compartments we have developed a novel application exploiting solid-state ²H-NMR spectroscopy. We utilise this method to probe the dynamics of intact sperm and nuclear envelope precursor membranes. We show, using mass spectrometry, that either multilamellar or small unilamellar vesicles of deuterium-labelled palmitoyl-oleoylphosphatidylcholine can be used to probe the dynamics of sperm cells or nuclear envelope precursor membrane vesicles, respectively. Using ²H-NMR we determine the order parameters of sperm cells and nuclear envelope precursor membrane vesicles. We demonstrate that whole sperm membranes are more dynamic than nuclear envelope precursor membranes due to the higher cholesterol levels of the latter. Our new application can be exploited as a generic method for monitoring membrane dynamics in whole cells, various subcellular membrane compartments and membrane domains in subcellular compartments.     

An off-line filtering ditch–pond system for diffuse pollution control at Wuhan City Zoo

An off-line filtering ditch–pond system was designed and constructed to control the small point and runoff pollution at the Wuhan City Zoo, Hubei Province, China. The quantity and quality of wastewater discharge and runoff from 16 rainfall events were measured to test the effectiveness of the off-line treatment train. The results showed that the water quality was improved and high retention rates for water and pollutants were also achieved by the off-line treatment train. In the outflows, the event mean concentrations (EMCs) of TSS, COD, TN, TDN, TP and TDP were reduced by 75%, 50%, 50%, 57%, 74% and 80% compared to the inflows. In 2005, the annual inflow volume in the catchment was 6783 m³ and the water retention rate was 80.1%. The retention rates in the annual loads of TSS, COD, TN and TP came to 86.4%, 85.5%, 83.9% and 82.9%, respectively. Therefore, the off-line filtering ditch–pond system was shown to be an effective and economical measure to control diffuse pollution. It would be worthwhile to extend the off-line treatment train to regions with limited land resources, especially in urban areas.     

气候和流域特征变化对淮河流域地表水文过程的影响

定量认识和理解气候与流域特征变化对淮河流域地表水文过程的影响,可以为科学管理淮河流域水资源提供重要的理论参考和技术支撑。评估了多控制因子联立求解归因方法的适用性,以此量化了淮河流域气候和Budyko参数n对不同年代蒸散发(ET)、径流变化(较基准期1961—1980年)的贡献,并且进行了归因分析,结果表明：1)多控制因子联立求解法可以准确有效地分离气候和参数n对ET和径流变化的贡献。2)在气候和参数n变化的共同影响下,20世纪80年代、90年代的ET和径流在沂沭泗河各水文分区均呈减小趋势,而在上游和中游各水文分区的变化则表现出明显的时空差异性。3)就各年代控制ET变化的主要因子,多数水文分区为参数n,其次为降水和潜在蒸散发(PET),分别集中在沂沭泗河地区和淮河上游。20世纪80年代,中游水文分区径流变化的主控因子为PET,其他水文分区则多为降水;而20世纪90年代和21世纪初多数水文分区的主控因子为参数n,其次为降水。总之,控制淮河流域ET和径流变化的物理机制具有明显的空间差异和年代际变化特征。     

Interplay between order-parameter and system parameter dynamics: considerations on perceptual-cognitive-behavioral mode-mode transitions exhibiting positive and negative hysteresis and on response times

A mathematical model is presented for the emergence of perceptual-cognitive-behavioral modes in psychophysical experiments in which participants are confronted with two alternatives. The model is based on the theory of self-organization and, in particular, the order parameter concept such that the emergence of a mode is conceptualized as an instability leading to the emergence of an appropriately defined order parameter. The order parameter model is merged with a second model that describes adaptation in terms of a system parameter dynamics. It is shown that the two-component model predicts hysteretic mode-mode transitions when control parameters are increased or decreased beyond critical values. The two-component model can account for both positive and negative hysteresis effects due to the interaction between order parameter and system parameter dynamics. Moreover, the model-based analysis reveals that response time curves look rather flat when response times are relatively decoupled from the mode-mode transition phenomenon. In general, response time curves exhibit a peaked close to the mode-mode transition point. In this context, the possibility is discussed that such peaked response time curves belong to the class of critical phenomena of self-organizing systems. In order to illustrate the relevance of peaked response time curves for future research and research reported in the past, results from a perceptual judgment experiment are reported, in which participants judged their ability to stand on a tilted slope for various angles of inclination. Response time curves were found that exhibited a peak around the mode-mode-transition points between “yes” and “no” responses.     

青海祁连瑞香狼毒的光谱差异特征提取

瑞香狼毒是分布在青海省高寒草甸的主要毒害草之一,近年来其迅速蔓延对当地畜牧业危害严重并使草地生态系统日趋退化.在海北州祁连县选取狼毒分布的典型退化草甸,采用2012—2014年狼毒盛花期获取的实测光谱数据,分析狼毒与牧草的光谱差异性.结果表明： 在350~900 nm的可见光 近红外波段,狼毒顶花的光谱反射特征明显异于狼毒叶片和同期牧草等绿色背景,顶花与绿色背景的光谱反射率差异主要体现在红谷和蓝谷.随着盖度的增加,狼毒群落光谱反射率整体升高,在近红外反射峰处狼毒群落与牧草群落光谱反射率具有最大差值,且不同盖度狼毒群落之间的差异性最明显.顶花与绿色背景以及狼毒群落与牧草群落的一阶导数光谱差异均体现在黄边幅值和蓝边幅值.狼毒群落盖度与光谱特征参量的线性回归分析表明,红谷与狼毒群落盖度的相关性最好(R²=0.94),反演狼毒群落盖度的精度最高.盛花期区分狼毒与牧草的主要光谱特征参量为红谷、蓝谷与近红外反射峰,其对应的红、蓝及近红外波段的组合可用于构建狼毒提取的敏感指数.     

Genetic analysis for main length ratio associated with morphological traits in Japanese flounder Paralichthys olivaceus

The objective of this study was to estimate genetic parameters of main length ratios associated with morphological traits in Paralichthys olivaceus. At 180, 240 and 360 days of age, body length (L₁), head length (L₂), body depth (L₃), caudal peduncle depth (L₄) and caudal‐peduncle length (L₅) were observed in 4757–5224 individuals from 52 full‐sib families. Based on these observed traits, the main length‐ratio traits including L₃:L₁, L₂:L₁, L₅:L₁ and L₄:L₃ were constructed. Three single‐trait animal models were used to examine the phenotypic variation of length‐ratio traits and were compared using the likelihood ratio test. As a result, the optimal model for all the analysed traits was determined as the model with the fixed, additive genetic and full‐sib family effects. Using the optimal model, animal model analysis for single trait showed that heritabilities were estimated to be low, ranging from 0·122 to 0·276. The estimates for all length‐ratio traits decreased while the days of age increased except for L₃:L₁. Multivariate animal model analysis indicated that within and among days of age, genetic correlations between length‐ratio traits were different in the direction and magnitude. Genetic parameter estimation of main length ratios would be helpful for genetic improvement of body shape in P. olivaceus.