The genome of the diatom Thalassiosira pseudonana: ecology, evolution, and metabolism

Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for approximately 20% of global carbon fixation. We report the 34 million-base pair draft nuclear genome of the marine diatom Thalassiosira pseudonana and its 129 thousand-base pair plastid and 44 thousand-base pair mitochondrial genomes. Sequence and optical restriction mapping revealed 24 diploid nuclear chromosomes. We identified novel genes for silicic acid transport and formation of silica-based cell walls, high-affinity iron uptake, biosynthetic enzymes for several types of polyunsaturated fatty acids, use of a range of nitrogenous compounds, and a complete urea cycle, all attributes that allow diatoms to prosper in aquatic environments.     

Genomic islands and the ecology and evolution of Prochlorococcus

Prochlorococcus ecotypes are a useful system for exploring the origin and function of diversity among closely related microbes. The genetic variability between phenotypically distinct strains that differ by less that 1% in 16S ribosomal RNA sequences occurs mostly in genomic islands. Island genes appear to have been acquired in part by phage-mediated lateral gene transfer, and some are differentially expressed under light and nutrient stress. Furthermore, genome fragments directly recovered from ocean ecosystems indicate that these islands are variable among cooccurring Prochlorococcus cells. Genomic islands in this free-living photoautotroph share features with pathogenicity islands of parasitic bacteria, suggesting a general mechanism for niche differentiation in microbial species.     

Gender,ecology, and the science of survival: Stories and lessons from Kenya

Sustainable development and biodiversity initiatives increasingly include ethnoscience, yet the gendered nature of rural people's knowledge goes largely unrecognized. The paper notes the current resurgence of ethnoscience research and states the case for including gendered knowledge and skills, supported by a brief review of relevant cultural ecology and ecofeminist field studies. The author argues the case from the point of view of better, more complete science as well as from the ethical imperative to serve women's interests as the “daily managers of the living environment”. In the interests of both objectives the paper advocates an ethnoscience research approach based on empowerment of rural people, rather than simple extraction of their knowledge. The Kenyan case study of women's agroforestry work follows their response to the drought and famine of 1985 and chronicles the unfolding discovery of women's ecological, political, and social science as gendered survival skills. The case is re-counted as a story, in keeping with an explicit choice to learn through participation and to report through storytelling. The experience of rural women and researchers during the drought provides several lessons for both groups about their respective knowledge systems, their agroforestry work, and the relationship of both to local and national political economy.     

我国虫草产业发展现状、问题及展望——虫草产业发展金湖宣言

\t\t\t\t\t目的\t\t\t\t\t筛选兰坪虫草优良菌株,并研究其不同极性部分的化学成分,旨在探究其功能性成分。\t\t\t\t\t\t\t\t\t\t\t\t\t方法\t\t\t\t\t通过薄层层析色谱分析(TLC)方法从49株兰坪虫草菌株中筛选出不同极性成分丰富的优良菌株。用不同极性溶剂对优良菌株的发酵产物进行成分萃取,通过硅胶柱层析、薄层色谱层析、凝胶柱层析和重结晶等方法对不同极性部分粗提物进行分离纯化,并对分离到的化合物进行核磁共振氢谱、碳谱测定。\t\t\t\t\t\t\t\t\t\t\t\t\t结果\t\t\t\t\t筛选得到综合指标最高的优良菌株OLLJ22,从其发酵培养物不同极性部分粗提物中分离得到31段粗品(乙醇部分10段,乙酸乙酯部分12段,石油醚部分9段),进一步分离和纯化得到7个单体化合物,分别鉴定为脂肪酸、甘油酯、乌苏酸、β-谷甾醇、尿苷、D-甘露醇和有机酸。\t\t\t\t\t\t\t\t\t\t\t\t\t结论\t\t\t\t\t对兰坪虫草菌株发酵产物不同极性部分的化学成分进行较系统的分离纯化,鉴定到7个化合物,其中乌苏酸为首次在广义虫草属中分离到。\t\t\t\t     

Living with the past: evolution, development, and patterns of disease

Epidemiological observations have led to the hypothesis that the risk of developing some chronic noncommunicable diseases in adulthood is influenced not only by genetic and adult life-style factors but also by environmental factors acting in early life. Research in evolutionary biology, developmental biology, and animal and human physiology provides support for this idea and suggests that environmental processes influencing the propensity to disease in adulthood operate during the periconceptual, fetal, and infant phases of life. This "developmental origins of health and disease" concept may have important biological, medical, and socioeconomic implications.     

快速城市化影响下超大型城市景观生态格局演变特征分析

针对超大型城市建设对景观生态格局及其变化定量研究的应用需求,基于多时相遥感变化监测和格网划分方法,结合景观指数对北京景观空间格局及动态变化进行定量分析,同时探究城市化对城市景观影响的阈值效应。结果表明:1)2000—2015年,由于北京城市化水平逐渐提高,导致建筑用地增加了56%,斑块破碎程度较低;而城市耕地及绿地景观有所减少、斑块分布不均,破碎程度上升;2)空间格局方面,由于建筑用地的覆盖及彼此间的高度连接,使城区景观破碎程度明显低于城郊,景观多样性水平呈下降趋势;3)回归分析表明城市化对城市景观破碎度有显著影响,相关系数达0.84,具体表现为倒U关系,即景观破碎度随城市化水平的提高呈先上升后下降的关系,城市化水平在51%～53%时达到峰值。