Assembly of local communities: consequences of an optimal body size for the organization of competitively structured communities

Much empirical evidence suggests that there is an optimal body size for mammals and that this optimum is in the vicinity of l00g. This presumably reflects an underlying fitness function that is greatest at this mass. Here, I combine such a fitness function with an equilibrium model of competitive character displacement to assess the potential influence of a globally optimal body size in structuring local ecological communities. The model accurately predicts the range of body sizes and the average difference in size for species in communities of varying species richness. The model also predicts a uniform spacing of body sizes, rather than the gaps and clumps in the sizes of coexisting species observed in real communities. Alternative explanations for this phenomenon are discussed. The allometric relationships that result in a body size optimum subsume a large number of characteristics associated with the physiological, behavioral, demographic, and evolutionary dynamics of the species. Further integration of the underlying dynamics (e.g. individual energetics) of these relationships into all hierarchical levels of ecology will have to incorporate multiple interactive sites, spatial heterogeneity, and phylogenetic structure, but it has the potential to provide important discoveries into the means by which natural selection operates.     

Hydroxycinnamic acid amides in fertile and cytoplasmic male sterile lines of maize

Hydroxycinnamic acid (HCA) amides in fertile and cytoplasmic male sterile lines of maize were determined in reproductive organs, developing grains and cobs. HCA amides occurred in large amounts in the anthers of fertile plants (line F7N) and were absent from the anthers of cytoplasmic male sterile lines (lines F7T and F7C). Restoration of fertility was associated with the production of these compounds (line FC31). Considerable variations were observed in the concentrations of HCA amides at different stages of growth and grain maturation. Changes of HCA amides in the grains which were to produce sterile plants followed a pattern similar to that obtained with the grains which were to produce fertile plants. Accumulation of HCA amides was substantially higher in fertile lines whatever their genotype (F7N, FC31 and F7T x FC31) than in sterile lines. Marked changes occurred in the HCA amide content of embryo and endosperm during grain development. Many changes in HCA amides were observed in cobs during development and maturation, but no substantial differences could be observed between fertile and sterile lines.     

Chemical equilibrium and E value of Zn (ZnE) in inceptisols and entisols of tropical india

Summary The chemical equilibrium and E value for Zn was calculated in 9 soils of Haryana (India) which represented mainly entisol and inceptisols. The rate of isotopic exchange between⁶⁵Zn and native soil Zn was quite rapid and radioactivity reduced to about 0.2 per cent of initial activity after 3 days but total Zn concentration in soil solution did not decrease. In 5 out of 9 soils equilibrium was established in 2 to 3 days. In typic ustochrepts having high clay content (3,4) equilibrium was attained in two days. In typic udipsamments (2), typic camborthids (8) and aquic vertic ustichrepts (9) it took 3 days to set equilibrium. Typic ustochrepts (5) took 5 days for equilibrium whereas typic ustipssaments (6) and typic camborthids of high O.C. did not attain equilibrium even in 7 days. This indicated that the chemistry and availability of Zn in soil would depend on soil types. When Zn_E was estimated by applying activity after equilibrium with carrier Zn and by applying activity with carrier Zn before equilibrium was set, there was no agreement in Zn_E in two methods. Increasing Zn_E with increasing Zn dose was observed by both methods only in alkaline typic ustochrept (4). In some soils higher E values than added amounts were observed, whereas, in soil 8 negative E values were obtained. The E values become erratic and are over estimated where complex reactions take place due to high pH, high O.C. and high complex forming elements.     

Regulation by testosterone of the glucosamine-6-phosphate synthase activity in the male reproductive organs of rat

Accessory reproductive organs of male rat were found to contain high activities of glucosamine-6-phosphate synthase (glucosaminephosphate isomerase (glutamine-forming), EC 5.3.1.19). Castration caused drastic reduction (75%) in the enzyme activity of ventral prostate. Testosterone propionate administration restored the enzyme activity while cortisol and estradiol-17β did not cause any effect. Cycloheximide blocked the stimulation caused by testosterone.     

DeepMHADTA: Prediction of Drug-Target Binding Affinity Using Multi-Head Self-Attention and Convolutional Neural Network

Drug-target interactions provide insight into the drug-side effects and drug repositioning. However, wet-lab biochemical experiments are time-consuming and labor-intensive, and are insufficient to meet the pressing demand for drug research and development. With the rapid advancement of deep learning, computational methods are increasingly applied to screen drug-target interactions. Many methods consider this problem as a binary classification task (binding or not), but ignore the quantitative binding affinity. In this paper, we propose a new end-to-end deep learning method called DeepMHADTA, which uses the multi-head self-attention mechanism in a deep residual network to predict drug-target binding affinity. On two benchmark datasets, our method outperformed several current state-of-the-art methods in terms of multiple performance measures, including mean square error (MSE), consistency index (CI), rm2, and PR curve area (AUPR). The results demonstrated that our method achieved better performance in predicting the drug–target binding affinity.     

Species specificity and intraspecific variation in the chemical profiles of Heliconius butterflies across a large geographic range

In many animals, mate choice is important for the maintenance of reproductive isolation between species. Traits important for mate choice and behavioral isolation are predicted to be under strong stabilizing selection within species; however, such traits can also exhibit variation at the population level driven by neutral and adaptive evolutionary processes. Here, we describe patterns of divergence among androconial and genital chemical profiles at inter‐ and intraspecific levels in mimetic Heliconius butterflies. Most variation in chemical bouquets was found between species, but there were also quantitative differences at the population level. We found a strong correlation between interspecific chemical and genetic divergence, but this correlation varied in intraspecific comparisons. We identified “indicator” compounds characteristic of particular species that included compounds already known to elicit a behavioral response, suggesting an approach for identification of candidate compounds for future behavioral studies in novel systems. Overall, the strong signal of species identity suggests a role for these compounds in species recognition, but with additional potentially neutral variation at the population level.     

Latitudinal patterns of reproductive effort in gamebirds and waterfowl: bucking the trend?

Clutch sizes of gamebirds decrease in a hyperbolic fashion towards the equator, but their clutch investment (total clutch mass as a proportion of female body weight) does not vary with latitude, regardless of whether body mass and phylogeny are factored out. In contrast, clutch sizes of wildfowl increase towards the tropics, but when corrected for body mass and phylogeny, no latitudinal pattern remains. Clutch investment by wildfowl peaks in the tropics, but this relationship becomes insignificant when body size and phylogeny are factored out. These contrasting patterns are explored in terms of habitat type, and the groups’ shared precocial development mode.     

鄱阳湖生态经济区生态系统服务价值预测与驱动力

鄱阳湖生态经济区是我国第一个上升到国家战略的生态经济区。利用鄱阳湖生态经济区2004、2008、2012、2016年的MODIS数据,获得4个对应期的土地利用/覆盖数据,参照修订的单位面积生态系统服务价值当量表与灰色GM(1,1)模型,预测了2016-2024年(间隔2 a)的生态系统服务价值数据,并对引起生态服系统务价值变化的驱动力进行了分析。结果表明,鄱阳湖生态经济区在2004-2016年间,草地、建设用地和未利用地面积增加,耕地、林地、水域面积减少,但2016-2024年的预测值变化率仅为-0.17%,表明该研究区生态系统服务价值即将进入一个相对稳定的状态;驱动力分析表明,人为综合干扰在空间分布上以中等影响强度干扰为主,城镇化率是区域总生态系统服务价值降低的首要驱动力,其次分别为非农业人口、人口密度、第一产业GDP、第二产业GDP、固定资产投资额、总GDP及第三产业GDP。建议加强土地利用规划与调控,控制城镇化建设用地扩展,调整产业结构、降低污染,促进鄱阳湖生态经济区总生态系统服务价值的提升。     

Design and comparison of gene-pyramiding schemes in animals

Marker-assisted gene pyramiding provides a promising way to develop new animal breeds or lines, in which genes responsible for certain favorable characters identified in different breeds or lines are incorporated. In consideration of features of animal populations, we proposed five schemes for pyramiding three genes, denoted Scheme A-E, and five schemes for pyramiding four genes, denoted Scheme F-J. These schemes are representative of the possible alternatives. We also provided an algorithm to compute the population sizes needed in each generation. We compared these schemes with respect to the total population size and the number of generations required under different situations. The results show that there is no scheme that is optimal in all cases. Among the schemes for pyramiding three genes from three lines (L1, L2 and L3), Scheme D (a three-way cross between the three lines are first performed, followed by a backcross to L1 and a subsequent intercross to obtain the desired genotype) has a significant advantage over the other schemes when the recombination rate between adjacent genes ranges from 0.1 to 0.4, while Scheme A (a two-way cross between L1 and L2 and a subsequent intercross are performed, followed by a cross with L3 and a subsequent intercross to obtain the desired genotype) is optimal when recombination rate is 0.5. Among schemes for pyramiding four genes from four lines (L1, L2, L3 and L4), Scheme I (seperately, a two-way cross between L1 and L2 (L3 and L4) followed by a backcross to L1 (L3) and a subsequent intercross are performed, then the offspring from the two sides are crossed and followed by a backcross to L1 and a subsequent intercross to obtain the desired genotype) is optimal when the recombination rate ranges from 0.1 to 0.4, while Scheme F (cross and subsequent intercross between the four lines are performed successively) is the optimal when the recombination rate is 0.5. We also disscuss how the animals' reproductive capacity, the probabilities of obtaining the desired genotypes and genetic distance between adjacent genes would affect the design of an optimal scheme.