防治荒漠化的“三圈”生态-生产范式机理及其功能

防治荒漠化的“三圈”生态-生产范式,是干旱生态系统优化与重建的新结构。根据在鄂尔多斯和新疆等地的研究和实践,从干旱生态系统结构、过程和功能来讨论荒漠化防治的“三圈”范式。地理圈层结构（地理地带性）是“三圈”范式的自然地理背景。从宏观尺度和功能方面划分,“三圈”范式在空间尺度上有大“三圈”和小“三圈”之分,大“三圈”控制洲际范围的荒漠化扩展及沙尘暴蔓延,小“三圈”则以控制区域性风沙活动、沙尘暴和就地起沙的危害。防治荒漠化工程是复杂的多元组合和多功能的系统,我国西北地区受荒漠化影响严重,宏观的大“三圈”与多区域的小“三圈”有机结合,形成圈圈相护、层层设防的严密防护与生产系统,有效地控制大范围风沙危害、改善地方气候与小气候,并对发展经济,提高人民生活发挥重要作用。因此,“三圈”范式的概念与结构既是以自然地理地带性为基础,又是人类对自然、环境与生态系统格局的规律认识,更是科学的人类恢复、重建干旱区生态环境与可持续发展的生态设计范式。     

Map and analysis of microsatellites in the genome of <Emphasis Type="Italic">Populus</Emphasis>: The first sequenced perennial plant

We mapped and analyzed the microsatellites throughout 284295605 base pairs of the unambiguously assembled sequence scaffolds along 19 chromosomes of the haploid poplar genome. Totally, we found 150985 SSRs with repeat unit lengths between 2 and 5 bp. The established microsatellite physical map demonstrated that SSRs were distributed relatively evenly across the genome of Populus. On average, These SSRs occurred every 1883 bp within the poplar genome and the SSR densities in intergenic regions, introns, exons and UTRs were 85.4%, 10.7%, 2.7% and 1.2%, respectively. We took di-, tri-, tetra-and pentamers as the four classes of repeat units and found that the density of each class of SSRs decreased with the repeat unit lengths except for the tetranucleotide repeats. It was noteworthy that the length diversification of microsatellite sequences was negatively correlated with their repeat unit length and the SSRs with shorter repeat units gained repeats faster than the SSRs with longer repeat units. We also found that the GC content of poplar sequence significantly correlated with densities of SSRs with uneven repeat unit lengths (tri-and penta-), but had no significant correlation with densities of SSRs with even repeat unit lengths (di-and tetra-). In poplar genome, there were evidences that the occurrence of different microsatellites was under selection and the GC content in SSR sequences was found to significantly relate to the functional importance of microsatellites.     

Identification of motivational state in adult male Atlantic walruses inferred from changes in movement and diving behavior

Motivational changes in animals are likely to be detectable retrospectively through observed changes in behavior. Breeding represents one of the strongest motivational states in mammals, and its timing is often tied to a seasonally optimal suite of environmental and physical conditions. While seasonal changes in behavior may be directly observable in some species, for others that breed cryptically or in difficult to access areas, detecting behavioral changes may only be feasible using data collected remotely. Herein, we explore whether behavioral changes can be used to infer motivational state for a wild, free‐ and wide‐ranging high arctic marine mammal, adult male Atlantic walruses (Odobenus rosmarus rosmarus). Using satellite‐relayed location and dive data from 23 adult male walruses instrumented in the Svalbard Archipelago, we identify seasonal movement to discrete geographic regions deep into winter pack ice. Adult male walrus diving behavior underwent marked seasonal movements between geographical areas that coincided with changes in light regime. At offshore wintering sites adult males (n = 4) shifted from a summer pattern of deep, long benthic dives to much shallower diving. Some males performed similar shallow, winter dive behavior at coastal locations (n = 12) suggesting that breeding might also occur around the coast of Svalbard. However, interpretation of behavioral changes of these coastal individuals was challenging. The presumed breeding sites at the winter off‐shore locations were situated in areas where polynyas are known to occur, making them a predictable resource even if they are located deep inside the winter pack‐ice. We demonstrate that remotely collected behavioral data can be used to identify seasonally explicit changes in the behavior of cryptic species.     

Differential Effect of Plant Lipids on Membrane Organization: SPECIFICITIES OF PHYTOSPHINGOLIPIDS AND PHYTOSTEROLS*

The high diversity of the plant lipid mixture raises the question of their respective involvement in the definition of membrane organization. This is particularly the case for plant plasma membrane, which is enriched in specific lipids, such as free and conjugated forms of phytosterols and typical phytosphingolipids, such as glycosylinositolphosphoceramides. This question was here addressed extensively by characterizing the order level of membrane from vesicles prepared using various plant lipid mixtures and labeled with an environment-sensitive probe. Fluorescence spectroscopy experiments showed that among major phytosterols, campesterol exhibits a stronger ability than β-sitosterol and stigmasterol to order model membranes. Multispectral confocal microscopy, allowing spatial analysis of membrane organization, demonstrated accordingly the strong ability of campesterol to promote ordered domain formation and to organize their spatial distribution at the membrane surface. Conjugated sterol forms, alone and in synergy with free sterols, exhibit a striking ability to order membrane. Plant sphingolipids, particularly glycosylinositolphosphoceramides, enhanced the sterol-induced ordering effect, emphasizing the formation and increasing the size of sterol-dependent ordered domains. Altogether, our results support a differential involvement of free and conjugated phytosterols in the formation of ordered domains and suggest that the diversity of plant lipids, allowing various local combinations of lipid species, could be a major contributor to membrane organization in particular through the formation of sphingolipid-sterol interacting domains.     

不同产地玉竹黄酮提取物体外抗氧化活性研究

以芦丁为参照,利用DPPH比色法和总还原能力测定法,对不同产地玉竹药材总黄酮体外抗氧化能力进行比较研究.结果表明:(1)不同产地玉竹总黄酮提取物对DPPH自由基均有较好的清除作用,但各样品间存在一定差异,在浓度为0.5 g·L-1时,山东泰安、安徽六安产玉竹黄酮DPPH清除作用达到最强,与芦丁相比无显著差异;(2)不同...     

Potential impacts of climate change on the environmental services of humid tropical alpine regions

Aim Humid tropical alpine environments are crucial ecosystems that sustain biodiversity, biological processes, carbon storage and surface water provision. They are identified as one of the terrestrial ecosystems most vulnerable to global environmental change. Despite their vulnerability, and the importance for regional biodiversity conservation and socio‐economic development, they are among the least studied and described ecosystems in the world. This paper reviews the state of knowledge about tropical alpine environments, and provides an integrated assessment of the potential threats of global climate change on the major ecosystem processes. Location Humid tropical alpine regions occur between the upper forest line and the perennial snow border in the upper regions of the Andes, the Afroalpine belt and Indonesia and Papua New Guinea. Results and main conclusions Climate change will displace ecosystem boundaries and strongly reduce the total area of tropical alpine regions. Displacement and increased isolation of the remaining patches will induce species extinction and biodiversity loss. Drier and warmer soil conditions will cause a faster organic carbon turnover, decreasing the below‐ground organic carbon storage. Since most of the organic carbon is currently stored in the soils, it is unlikely that an increase in above‐ground biomass will be able to offset soil carbon loss at an ecosystem level. Therefore a net release of carbon to the atmosphere is expected. Changes in precipitation patterns, increased evapotranspiration and alterations of the soil properties will have a major impact on water supply. Many regions are in danger of a significantly reduced or less reliable stream flow. The magnitude and even the trend of most of these effects depend strongly on local climatic, hydrological and ecological conditions. The extreme spatial gradients in these conditions put the sustainability of ecosystem management at risk.     

Calmodulin genes in zebrafish (revisited)

Calmodulin (CaM), a ubiquitous protein, ancestral in early eukaryotes, regulates a large number of physiologically important functions by activating other proteins, some of them enzymes, usually in response to changes in the local concentration of calcium ions. Invertebrates possess one gene that codes for CaM. Among vertebrates, mammals display three genes that code for a 100% identical CaM molecule, while for zebra fishes etc., a non-mammalian vertebrate, we reported earlier the existence of four such genes. The number of multiple genes coding for a 100% identical CaM molecule present in the zebra fish genome, however, is corrected here, from the four, as previously suggested, to six (alpha, alpha2, beta, beta2, gamma and gamma 2). Identification of each of these genes is readily achieved upon examination of the characteristic 5 and 3 UTRs within their respective mRNAs even though we do not know at present what role these UTRs might play. A scanning of the 3 UTRs for short homology elements among the six genes (and a comparison with the human type I, II, and III CaM 3 UTRs) also suggests that duplication processes for three genes resulted in the formation of six such genes. As they become available, the promoter regions for these six genes should be scanned for possible identification of putative regulatory elements if we are to understand the need for the uniquely rigid evolutionary maintenance of these six genes. A comparison of the promoter regions for the beta and beta 2 genes is presented in this paper. A few common short homologous elements appear to be retained in these generally highly variant two regions, but conclusions about differential expression controls must be delayed until the promoter regions for all the other CaM genes have been examined.     

Life Cycle Inventory Information of the United States Electricity System (11/17 pp)

Goal and Scope This study estimates the life cycle inventory (LCI) of the electricity system in the United States, including the 10 NERC (North American Electric Reliability Council) regions, Alaska, Hawaii, off-grid non-utility plants and the US average figures. The greenhouse gas emissions associated with the United States electricity system are also estimated. Methods The fuel mix of the electricity system based on year 2000 data is used. The environmental burdens associated with raw material extraction, petroleum oil production and transportation for petroleum oil and natural gas to power plants are adopted from the DEAMTM LCA database. Coal transportation from a mining site to a power plant is specified with the data from the Energy Information Administration (EIA), which includes the mode of transportation as well as the distance traveled. The gate-to-gate environmental burdens associated with generating electricity from a fossil-fired power plant are obtained from the DEAMTM LCA database and the eGRID model developed by the United States Environmental Protection Agency. For nuclear power plants and hydroelectric power plants, the data from the DEAMTM LCA database are used.Results and Discussion Selected environmental profiles of the US electricity system are presented in the paper version, while the on-line version presents the whole LCI data. The overall US electricity system in the year 2000 released about 2,654 Tg CO2 eq. of greenhouse gas emissions based on 100-year global warming potentials with 193 g CO2 eq. MJe–1 as an weighted average emission rate per one MJ electricity generated. Most greenhouse gases are released during combusting fossil fuels, accounting for 78–95% of the total. The greenhouse gas emissions released from coal-fired power plants account for 81% of the total greenhouse gas emissions associated with electricity generation, and natural gas-fired power plants contribute about 16% of the total. The most significant regions for the total greenhouse gas emissions are the SERC (Southeastern Electric Reliability Council) and ECAR (East Central Area Reliability Coordination Agreement) regions, which account for 22% and 21% of the total, respectively. A sensitivity analysis on the generation and consumption based calculations indicates that the environmental profiles of electricity based on consumption are more uncertain than those based on generation unless exchange data from the same year are available because the exchange rates (region to region import and export of electricity) vary significantly from year to year.Conclusions and Outlook Those who are interested in the LCI data of the US electricity system can refer to the on-line version. When the inventory data presented in the on-line version are used in a life cycle assessment study, the distribution and transmission losses should be taken into account, which is about 9.5% of the net generation [1]. The comprehensive technical information presented in this study can be used in estimating the environmental burdens when new information on the regional fuel mix or the upstream processes is available. The exchange rates presented in this study also offer useful information in consequential LCI studies.