The spatial distribution of cereal bioenergy potential in China

Biomass energy that exists in crop residues can be used for electricity generation and fuel production. However, its spatial distribution has formed a bottleneck in its utilization. This study introduces a data fusion method that uses the Net Primary Productivity (NPP) product of the Moderate‐resolution Imaging Spectroradiometer (MODIS) data as a weighting factor to downscale crop statistics from a county scale to a 1 km² spatial resolution using GIS to accurately map the spatial distribution of cereal bioenergy potential in China. The study demonstrates that the combination of remote sensing and statistical methods improves both spatial resolution and accuracy of the results, and resolves errors and uncertainties stemming from remote sensing processes. The results of the study will allow better decision making for siting biomass power plants, which will in turn reduce the cost of transportation of materials and increase the use of bioenergy.     

The influence of Triticum aestivum density, sowing pattern and nitrogen fertilization on leaf area index and its spatial variation

We investigated leaf area index (LAI) and its spatial variation early in the growing season in Triticum aestivum (spring wheat) sown in two spatial patterns (standard rows and a uniform pattern), at three densities (204, 449 and 721 seeds m⁻²), and two nitrogen fertilization levels (0 and 80 kg nitrogen ha⁻¹). Our main hypothesis was that a more uniform distribution of individual plants does not affect overall LAI but reduces its spatial variation. We used the number of leaves touching a vertical pin (LAI*) as a measure of LAI. LAI* increased with sowing density, nitrogen fertilization and, contrary to our hypothesis, spatial uniformity. The coefficient of variation of LAI* was higher (1) at lower sowing density, (2) without nitrogen fertilizer and (3) in the row pattern. Both the increase in LAI and the decrease in its variation in more spatially uniform crops may contribute to increased weed suppression and increased yield.     

Concordance of bacterial communities of two tick species and blood of their shared rodent host

High‐throughput sequencing is revealing that most macro‐organisms house diverse microbial communities. Of particular interest are disease vectors whose microbiome could potentially affect pathogen transmission and vector competence. We investigated bacterial community composition and diversity of the ticks Dermacentor variabilis (n = 68) and Ixodes scapularis (n = 15) and blood of their shared rodent host, Peromyscus leucopus (n = 45) to quantify bacterial diversity and concordance. The 16S rRNA gene was amplified from genomic DNA from field‐collected tick and rodent blood samples, and 454 pyrosequencing was used to elucidate their bacterial communities. After quality control, over 300 000 sequences were obtained and classified into 118 operational taxonomic units (OTUs, clustered at 97% similarity). Analysis of rarefied communities revealed that the most abundant OTUs were tick species‐specific endosymbionts, Francisella and Rickettsia, and the commonly flea‐associated bacterium Bartonella in rodent blood. An Arsenophonus and additional Francisella endosymbiont were also present in D. variabilis samples. Rickettsia was found in both tick species but not in rodent blood, suggesting that it is not transmitted during feeding. Bartonella was present in larvae and nymphs of both tick species, even those scored as unengorged. Relatively, few OTUs (e.g. Bartonella, Lactobacillus) were found in all sample types. Overall, bacterial communities from each sample type were significantly different and highly structured, independent of their dominant OTUs. Our results point to complex microbial assemblages inhabiting ticks and host blood including infectious agents, tick‐specific endosymbionts and environmental bacteria that could potentially affect arthropod‐vectored disease dynamics.     

Mice recognize the center of an enclosure

In recent years, it has been shown that animals can localize the geometric center of an area by reference to the shape of the environment. We trained a group of mice (experimental group) to search for a pellet hidden under sand in the center of a square-shaped dry maze. Three weeks later, they were tested in a triangular enclosure half the size of the training area and a circular enclosure double the size of the training area to see transfer to these enclosures. We compared their searching behavior with that of subjects that had received no training. The results show that the experimental group searched the geometric center of each enclosure in both transfer tests, while the untrained control group walked along the walls. This indicates that the experimental group localized the center not by reference to the absolute distance from the corners but by equal distances from all walls (geometric center).     

基于空间分析的保护生物学研究

 保护生物学家和生态学家早就认识到只有准确地辨识保护对象的空间位置、 范围、 及其相邻的关系(例如边缘)和连接度, 以及依存的地形和气候等生境条件, 才能发现生物种群和生境在空间的扩散与收缩、 增长与灭绝的动态, 揭示分布的格局, 从而系统、 全面地了解保护对象和生境的存在状态、 破碎程度和变化趋势, 进行有效的自然保护。 得益于新兴的空间分析技术, 保护生物学自20世纪90年代以来取得了很大的进步。基于空间分析的保护生物学研究是最近10年左右大力发展的新保护生物学的重要基础。 该文结合作者的研究工作,综述了基于空间分析的保护生物学项目, 探讨了保护生物学发展历史、 主要研究方法与应用、 以及今后的可能发展趋势。 在生物多样性的丰度和分布的空间解绎部分,通过综述世界保护监测中心的图解全球生物多样性的工作, 如国家尺度的生物多样性水平、 植物多样性的分布中心和维管束植物科的多样性等的空间分布 ,介绍了 Dobson等图示美国主要濒危植物、 鸟类、 鱼类和软体动物等4个主要类群在县(County) 为基本空间单位上分布的空间格局, 讨论了生物多样性空间解绎的意义。在第二部分用世界资源研究所的全球森林监测(Global forest watch)项目, 美国的国家保护缺失区分析(GAP analysis)项目, 美国林务局的无路自然区域(Roadless area)保护项目和加拿大自然审计(Nature audit)项目, 以及北美和东亚生物多样性空间分布的比较分析和生物入侵的空间分析等具体实例来说明生物多样性空间分布变化比较分析方法的应用。 过去20年来, 面向空间格局的生态学和保护生物学研究得到了快速的发展, 特别是空间格局的描述、 由地统计演变而成的空间统计、 地理信息系统、 基于个体(或栅格)的空间解绎模拟模型、 基于斑块(Patch)的种群理论及其发展(如复合种群理论, 源 汇模型等)等。在第三部分, 以美国森林破碎度空间格局分析和美国太平洋西北演替后期森林的空间格局分析为例, 介绍了空间格局分析在保护生物学中的应用。 同时介绍了澳大利亚保护生态学家Lindenmayer 和美国著名景观生态学家Franklin 2002年提出的模板(Matrix)保护理论,把保护的眼光不局限在面积不多而且分散的保护区中,应注意景观模板和保护区相邻的原生区域的综合保护, 这样将大大扩展保护的范围, 并且平衡保护与发展的关系。最后, 介绍了在保护生物学中已有一定应用的空间模型和模拟, 包括了空间解绎模型(Spatial explicit model)、 基于过程(Process-based)的空间模拟模型、 面向代理(Agent-based)的空间适应模拟模型(SWAM)以及与此有关的动态全球植被模型(DGVM)。 通过上面的讨论和综述, 预测一个新的保护生物学的分支: 空间保护生物学, 已经逐渐成熟问世, 这门基于现代信息技术和空间技术的新学科已经而且还将为全球生物多样性的研究和保育作出重大的贡献。     

Evaluating the capacity of plant DNA barcodes to discriminate species of cotton (Gossypium: Malvaceae)

Although two plastid regions have been adopted as the standard markers for plant DNA barcoding, their limited resolution has provoked the consideration of other gene regions, especially in taxonomically diverse genera. The genus Gossypium (cotton) includes eight diploid genome groups (A–G, and K) and five allotetraploid species which are difficult to discriminate morphologically. In this study, we tested the effectiveness of three widely used markers (matK, rbcL, and ITS2) in the discrimination of 20 diploid and five tetraploid species of cotton. Sequences were analysed locus‐wise and in combinations to determine the most effective strategy for species identification. Sequence recovery was high, ranging from 92% to 100% with mean pairwise interspecific distance highest for ITS2 (3.68%) and lowest for rbcL (0.43%). At a 0.5% threshold, the combination of matK+ITS2 produced the greatest number of species clusters. Based on ‘best match’ analysis, the combination of matK+ITS2 was best, while based on ‘all species barcodes’ analysis, ITS2 gave the highest percentage of correct species identifications (98.93%). The combination of sequences for all three markers produced the best resolved tree. The disparity index test based on matK+rbcL+ITS2 was significant (P < 0.05) for a higher number of species pairs than the individual gene sequences. Although all three barcodes separated the species with respect to their genome type, no single combination of barcodes could differentiate all the Gossypium species, and tetraploid species were particularly difficult.     

How to deal with neglected tropical diseases in the light of an African ethic

Many countries in Africa, and more generally those in the Global South with tropical areas, are plagued by illnesses that the wealthier parts of the world (mainly ‘the West’) neither suffer from nor put systematic effort into preventing, treating or curing. What does an ethic with a recognizably African pedigree entail for the ways various agents ought to respond to such neglected diseases? As many readers will know, a characteristically African ethic prescribes weighty duties to aid on the part of those in a position to do so, and it therefore entails that there should have been much more contribution from the Western, ‘developed’ world. However, what else does it prescribe, say, on the part of sub‐Saharan governments and the African Union, and are they in fact doing it? I particularly seek to answer these questions here, by using the 2013‐16 Ebola crisis in West Africa to illustrate what should have happened but what by and large did not.     

Evolution of the Dynein Heavy Chain Family in Ciliates

Dynein heavy chains are motor proteins that comprise a large gene family found across eukaryotes. We have investigated this gene family in four ciliate species: Ichthyophthirius, Oxytricha, Paramecium, and Tetrahymena. Ciliates appear to encode more dynein heavy chain genes than most eukaryotes. Phylogenetic comparisons demonstrated that the last common ancestor of the ciliates that were examined expressed at least 14 types of dynein heavy chains with most of the expansion coming from the single‐headed inner arm dyneins. Each of the dyneins most likely performed different functions within the cell.     

Effects of cyanobacteria,fish kairomones,and the presence of ostracods on the demography of Simocephalus vetulus (Cladocera)

Simocephalus vetulus is a large (2.0–4.0 mm at maturity) cladoceran often found in the littoral region of lakes and ponds, and capable of moderate growth rates even on poor‐quality cyanobacterial diets. It frequently co‐occurs with fishes and similar sized ostracods such as Heterocypris incongruens, but little is known of its response to fish kairomones or its interactions with potential competitors. We studied the demographic responses of S. vetulus fed the green alga Scenedesmus acutus, Microcystis cf. aeruginosa strain A, Microcystis cf. aeruginosa strain B, or Limnothrix sp. Experiments were conducted separately and together in the presence of Heterocypris incongruens and cichlid fish (Oreochromis) kairomones. A diet of Limnothrix sp. resulted in the lowest population growth rate (0.21±0.023 d^?1), while on diets of S. acutus or Microcystis, population growth was higher (0.30±0.009 d^?1). The presence of ostracods resulted in significantly higher growth rates of S. vetulus fed Limnothrix (0.33±0.01 d^?1), but not Microcystis or S. acutus. Regardless of the diet, the presence of fish kairomones resulted in significantly higher growth rates as compared with controls, particularly when ostracods were also present. Coexistence with ostracods may be beneficial to S. vetulus, particularly when food quality is poor.     

Methylation of ELOVL2 gene as a new epigenetic marker of age

The discovery of biomarkers able to predict biological age of individuals is a crucial goal in aging research. Recently, researchers' attention has turn toward epigenetic markers of aging. Using the Illumina Infinium HumanMethylation450 BeadChip on whole blood DNA from a small cohort of 64 subjects of different ages, we identified 3 regions, the CpG islands of ELOVL2, FHL2, and PENK genes, whose methylation level strongly correlates with age. These results were confirmed by the Sequenom's EpiTYPER assay on a larger cohort of 501 subjects from 9 to 99 years, including 7 cord blood samples. Among the 3 genes, ELOVL2 shows a progressive increase in methylation that begins since the very first stage of life (Spearman's correlation coefficient = 0.92) and appears to be a very promising biomarker of aging.