我国生态补偿研究中的科学问题

我国生态补偿的研究始于20世纪80年代对生态学意义上生态补偿的探讨和经济学意义上生态补偿的摸索;联合国环境与发展大会后,进入主动的基于环境损失赔偿的理论探讨阶段;随着生态保护的加强、生态工程的实施以及保护和发展矛盾的加剧,生态补偿涵义拓展到对生态环境保护者进行补偿,进入理论和实践相结合的阶段,并成为国内社会各界的热点问题。但是目前生态补偿的涵义、理论依据和补偿标准等生态补偿研究的核心问题仍然存在不确定性。我国生态补偿涵义经历了从生态学意义到经济学意义的发展历程,目前阶段的生态补偿涵义与国际上的"生态系统服务付费"比较接近。理清生态补偿费与环境费、资源费的关系是生态补偿定位的关键,主要是确定与后者的包含或者补充关系;生态补偿的环境经济学理论来源是基本一致的,即环境外部成本内部化原理和公共物品理论,但是生态系统服务作为生态补偿的理论依据还存在基于效益补偿还是基于价值补偿的争论;生态补偿标准确定主要包括基于生态系统服务量化、成本(机会成本)或通过供需双方的博弈等方法,目前仍然处于探索阶段。上述科学问题是决定生态补偿实施的可行性和有效性的关键性问题,需要从我国的实际出发,从不同区域的现实出发结合理论探讨和实践需求进行研究,建议日后加强以下几个方面的研究:(1)与现实需求一致的生态补偿概念的确定和科学定位;(2)以现实有效性为基础的理论依据和补偿标准计算;(3)基于利益相关方多方参与的生态补偿机制研究;(4)生态系统服务研究与生态补偿研究的结合。     

Multiple spatial-scale resource selection function models in relation to human disturbance for moose in northeastern China

The moose (Alces alces cameloides) population in northeastern China is on the southernmost edge of its distribution in Asia. A survey was conducted to determine moose resource selection and the effects of human disturbance on moose in a study area of 20,661 ha located on the northwestern slope of the Lesser Khingan Mountains, located in northeastern China. Predictive models of resource selection were developed using logistic and autologistic regression. All models considered resource variable selection at two spatial scales, patch and landscape. At the patch scale, moose preferred larger birch (Betula platyphylla) patches, but avoided larger tamarack (Larix gmelinii) patches. At the landscape scale, moose preferred higher densities of tamarack patches, i.e., heterogeneity of tamarack stands, selected areas with more abundant annual shoots, terrain conducive to better concealment, higher altitudes and areas saturated with soil moisture. Roads and forest harvest intervals were identified as important human disturbance factors. This is the first time that moose have been reported to avoid roads, and the avoidance distance was nearly 3 km. We believe that in this region moose under the influence of roads are behaviorally plastic, compared with the indifference of moose to the presence of roads in other regions. Moose avoided forest areas logged more than 3 years previously and preferred areas logged 1–2 years previously. In addition, it may be necessary to monitor the effect of the dynamic of density of roe deer on the spatial distribution of the moose population.     

退耕区域发展碳汇产业的生态经济学思考

碳汇产业,即利用植物吸收二氧化碳的潜力及规律,在人工适度干预下获得清洁空气、满足人们生产和生活对生态环境需求的产业,为原有相对均衡或稳定的农业产业-资源系统的优化升级提供突破口和新的增长点.退耕区域生态系统服务中,固碳释氧功能的经济显化、碳汇潜力的迅速提高,以及国内外碳汇交易与碳汇市场的兴起等,为碳汇产业的发展奠定了理论和现实基础.随着碳汇产业的发展,生产经营者必然以提高碳汇产出为核心,形成对碳源的控制及对碳贮量增加路径的开发,重新布局农业产业-资源结构,因而为退耕区域可持续发展带来新的活力;同时,也隐含了下一步需要研发的重点,即碳汇产业融入后的农业产业-资源的配置结构及良性耦合机制.     

Minimizing false positives in kinase virtual screens

In spite of recent improvements in docking and scoring methods, high false-positive rates remain a common issue in structure-based virtual screening. In this study, the distinctive features of false positives in kinase virtual screens were investigated. A series of retrospective virtual screens on kinase targets was performed on specifically designed test sets, each combining true ligands and experimentally confirmed inactive compounds. A systematic analysis of the docking poses generated for the top-ranking compounds highlighted key aspects differentiating true hits from false positives. The most recurring feature in the poses of false positives was the absence of certain key interactions known to be required for kinase binding. A systematic analysis of 444 crystal structures of ligand-bound kinases showed that at least two hydrogen bonds between the ligand and the backbone protein atoms in the kinase hinge region are present in 90% of the complexes, with very little variability across targets. Closer inspection showed that when the two hydrogen bonds are present, one of three preferred hinge-binding motifs is involved in 96.5% of the cases. Less than 10% of the false positives satisfied these two criteria in the minimized docking poses generated by our standard protocol. Ligand conformational artifacts were also shown to contribute to the occurrence of false positives in a number of cases. Application of this knowledge in the form of docking constraints and post-processing filters provided consistent improvements in virtual screening performance on all systems. The false-positive rates were significantly reduced and the enrichment factors increased by an average of twofold. On the basis of these results, a generalized two-step protocol for virtual screening on kinase targets is suggested.     

环境微生物群落功能研究的新方法和新策略

微生物群落在驱动生物地球化学循环中扮演着重要角色,传统的研究方法可对微生物群落进行遗传结构的解析,但不能有效地与功能研究耦联.概述了近年发展起来的基于核酸和蛋白质水平的分子生物学新方法--环境mRNA 和 rRNA同时荧光原位杂交(FISH)、寡核苷酸微阵列技术(Oligonucleotide Microarray)、 稳定性同位素联合宏基因组学(SIP-enabled Metagenomics)和环境蛋白质组学(Metaproteomics)在环境微生物群落功能研究中的应用,并且对其发展趋势进行了分析和展望.     

水稻根系通气组织与根系泌氧及根际硝化作用的关系

通过根箱土培试验研究了不同产量籼稻品种中旱22(ZH,高产品种)及禾盛10号(HS,低产品种)苗期根系生长、通气组织发育、根系径向泌氧量(radial oxygen loss,ROL)以及根表和根际土壤硝化强度差异。结果表明,除水稻播种40 d时二者根数量和根干重无显著差异外,ZH根直径、根数量和根干重均显著高于HS,二者差异尤其表现在根系生物量差异。两个水稻品种在距根尖20 mm处均可见辐射状通气组织,ZH皮层薄壁细胞已经完全崩溃形成连接中柱和外皮层的纵向气腔,而HS皮层薄壁细胞未发生完全离解,但仍能观察到明显的连接中柱和外皮层的纵向气腔的形成。同时ZH外皮层厚壁细胞体积较小,排列紧密,细胞壁增厚程度大;而HS外皮层厚壁细胞体积相对较大,排列疏松,细胞壁增厚程度相对较小。表明高产品种通气组织发育比低产品种更加完善,表现为ZH根孔隙度(porosity of root,POR)显著高于HS,且高产品种对水稻根系ROL的屏蔽作用较低产品种更强,为根系提供更充足的氧气供应,促进根系生长。除了水稻播种后40 d时ZH和HS单根ROL无显著差异外(P<0.05),ZH单株、单位重量以及单根ROL均显著高于HS(P<0.01)。两个水稻品种硝化强度均表现为根际土壤显著高于根表土壤 (P<0.01),前者大约是后者的3-6倍。两个品种根表土壤硝化强度无显著差异,而ZH根际土壤硝化强度均显著高于HS。相关性分析结果表明水稻根际土壤硝化强度和整株水稻ROL呈极显著正相关关系(r=0.803,P<0.01),和水稻POR也呈现极显著正相关关系(r=0.808,P<0.01),同时和根系直径、数量和干重均呈极显著正相关关系(P<0.01)。而根表土壤硝化强度和以上指标均无相关关系。由于硝化作用是好氧过程,因此高产品种由于根系发达,通气组织发育好,相应ROL也较大,造成根际土壤氧气含量高,从而可能导致根际土壤硝化强度显著高于低产品种。     

A chromosome‐level genome assembly reveals the genetic basis of cold tolerance in a notorious rice insect pest,Chilo suppressalis

The rice stem borer, Chilo suppressalis, is one of the most damaging insect pests to rice production worldwide. Although C. suppressalis has been the focus of numerous studies examining cold tolerance and diapause, plant–insect interactions, pesticide targets and resistance, and the development of RNAi‐mediated pest management, the absence of a high‐quality genome has limited deeper insights. To address this limitation, we generated a draft C. suppressalis genome constructed from both Illumina and PacBio sequences. The assembled genome size was 824.35 Mb with a contig N₅₀ of 307 kb and a scaffold N₅₀ of 1.75 Mb. Hi‐C scaffolding assigned 99.2% of the bases to one of 29 chromosomes. Based on universal single‐copy orthologues (BUSCO), the draft genome assembly was estimated to be 97% complete and is predicted to encompass 15,653 protein‐coding genes. Cold tolerance is an extreme survival strategy found in animals. However, little is known regarding the genetic basis of the winter ecology of C. suppressalis. Here, we focused our orthologous analysis on those gene families associated with animal cold tolerance. Our finding provided the first genomic evidence revealing specific cold‐tolerant strategies in C. suppressalis, including those involved in glucose‐originated glycerol biosynthesis, triacylglycerol‐originated glycerol biosynthesis, fatty acid synthesis and trehalose transport‐intermediate cold tolerance. The high‐quality C. suppressalis genome provides a valuable resource for research into a broad range of areas in molecular ecology, and subsequently benefits developing modern pest control strategies.     

VARIABLE SELECTION ON EUROSTA'S GALL SIZE,I: THE EXTENT AND NATURE OF VARIATION IN PHENOTYPIC SELECTION

Natural fluctuations in environmental conditions are likely to induce variation in the intensity or direction of natural selection. A long-term study of the insect, Eurosta solidaginins Fitch (Diptera; Tephritidae), which induces stem galls on the perennial herb Solidago altissima (Asteraceae) was performed to explore the patterns of variation in phenotypic selection. The intensity of selection imposed by parasitoids and predators on gallmaking larvae, for gall size, was measured across 16 populations over the course of 4 generations, for a total of 64 population-generations. Directional selection was quantified by i, the selection intensity, and variance selection by j‘, a measure of the intensity of selection on phenotypic variance. Size-dependent attack by parasitoids caused upward directional selection (mean i_p = 0.42; SE = 0.023), while size-dependent bird attack favored larvae that induced smaller galls (mean i_b = -0.07; SE = 0.013. The mean net directional selection intensity was 0.35 (SE = 0.030), which indicates that insects inducing larger galls are generally favored by selection. The opposing patterns of size-dependent attack resulted in stabilizing selection in half the population generations, with an overall average. j‘ of -0.11 (SE = 0.078). The magnitude of directional selection was strongly influenced by the population mean gall size and weakly by the optimal gall size. The intensity of variance selection was strongly influenced by the shape of the fitness function, with sigmoidal and Gaussian-like shapes causing greater depletion of phenotypic variance.     

Biological weighting functions for DNA damage in sea urchin embryos exposed to ultraviolet radiation

Laboratory experiments examining the effects of ultraviolet radiation (UVR, 290-400 nm) on DNA damage were carried out using the embryos of three species of sea urchins from different habitats; Strongylocentrotus droebachiensis from the Gulf of Maine, Sterechinus neumayeri from the Antarctic, and Evechinus chloroticus from New Zealand. All three species exhibited significant amounts of accumulated DNA damage, measured as cyclobutane pyrimidine dimers (CPD) photoproducts, when exposed to UVR in the laboratory. Biological weighting functions (BWFs) revealed that S. neumayeri has significantly higher sensitivity to UVR-induced DNA damage across most of the UVR spectrum compared to the other two species, and all species were observed to have weightings in the ultraviolet-A (UVA, 320-400 nm) portion of the spectrum. The increased sensitivity to ultraviolet-B (290-320 nm) and UVA in S. neumayeri is correlated with the lowest concentration of UVR absorbing compounds observed in the embryos of the three species of urchin used in this study. Sea urchin embryos and larvae in the respective habitats of the species tested are known to occur within 5 m of the surface of the ocean where both UVB and UVA wavelengths occur. Solar irradiances of UVR at a depth of 5 m, weighted using the urchin DNA damage BWFs, show that E. chloroticus receives the greatest amount of biologically effective UVR despite having the lowest wavelength dependent weightings for DNA damage when compared to the other two species.     

Effect of indinavir used alone or in double or triple combination with AZT and ddC on human immune functions

Indinavir (IDV) is a potent and selective human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) widely used in antiretroviral therapy, but its effects on the immune system are relatively unknown. In this study we have investigated the in vitro effect of IDV on normal human peripheral blood mononuclear cells (PBMC). We used the drug alone or in double and triple combination with AZT and ddC to assess whether IDV interferes with the previously observed immunomodulatory effects induced by AZT and ddC. We found that proliferative response, induction of immunoglobulins (Ig) production and cytokine production was not modulated by IDV. More importantly, IDV used in double or triple combination with AZT and ddC, does not further strenghten the inhibition of proliferative response induced by AZT and is able to abrogate the inhibitory effect induced by ddC on proliferative response. Similarly, IDV/AZT, IDV/ddC and IDV/AZT/ddC combinations does not strenghten the modulation of TNF-alpha, IFN-gamma and IL-4 induced by AZT, ddC and AZT/ddC. On the other hand, IDV neutralizes the up-regulating effects of AZT on IL-2 production while the up-regulating effects of ddC on IL-2 production is not affected. These data suggest that IDV used in combination with AZT and ddC did not add any further immunotoxicity.