各个肠段IL-10 水平与气候变化的关系

目的：季节气候的变化能够影响人体肠道的生理功能和病理变化,这在中医学的长期临床实践和现代流行病学调查中都有 记载和证实,但是相关的机制并不清晰。因此本研究通过观察不同气候下大鼠空肠、回肠、结肠的IL-10 水平变化,从而从免疫功 能的角度探讨季节气候变化对肠道功能的影响机制。方法：根据北京地区气象资料,大致可将一年之中气候划分为五种季节气 候,分别由春、夏、长夏、秋和冬来代表;实验分为正常组和松果腺摘除模型组;分别把两组大鼠饲养五种正常自然季节气候下一 个月,然后用ELISA 方法检测大鼠空肠、回肠和结肠的IL-10 水平。结果：①正常组空肠IL-10水平在长夏季节明显升高（P<0. 001）;② 回肠的IL-10 表达水平则是在长夏与冬季这两个季节含量最多（P<0.01, P<0.001）;③ 结肠IL-10 含量则在冬季呈现出高 峰（P<0.01）。结论：季节气候变化对肠道功能的影响的机制与肠道免疫功能的季节性变化有关。具体表现在：① 肠道IL-10 水平 是有季节气候变化规律的,而且空肠、回肠和结肠表现出来的季节气候规律是不相同的。②松果腺参与了肠道免疫功能气候调 节过程。     

各个肠段IL-10水平与气候变化的关系

目的：季节气候的变化能够影响人体肠道的生理功能和病理变化,这在中医学的长期临床实践和现代流行病学调查中都有记载和证实,但是相关的机制并不清晰。因此本研究通过观察不同气候下大鼠空肠、回肠、结肠的IL-10水平变化,从而从免疫功能的角度探讨季节气候变化对肠道功能的影响机制。方法：根据北京地区气象资料,大致可将一年之中气候划分为五种季节气候,分别由春、夏、长夏、秋和冬来代表;实验分为正常组和松果腺摘除模型组;分别把两组大鼠饲养五种正常自然季节气候下一个月,然后用ELISA方法检测大鼠空肠、回肠和结肠的IL-10水平。结果：①正常组空肠IL-10水平在长夏季节明显升高（P〈0．001）;②回肠的IL-10表达水平则是在长夏与冬季这两个季节含量最多（P〈0．01,P〈0．001）;③结肠IL-10含量则在冬季呈现出高峰（P〈0．01）。结论：季节气候变化对肠道功能的影响的机制与肠道免疫功能的季节性变化有关。具体表现在：①肠道IL-10水平是有季节气候变化规律的,而且空肠、回肠和结肠表现出来的季节气候规律是不相同的。②松果腺参与了肠道免疫功能气候调节过程。     

Bioethics and Climate Change: A Response to Macpherson and Valles

Two articles published in Bioethics recently have explored the ways that bioethics can contribute to the climate change debate. Cheryl Cox Macpherson argues that bioethicists can play an important role in the climate change debate by helping the public to better understand the values at stake and the trade‐offs that must be made in individual and social choices, and Sean Valles claims that bioethicists can contribute to the debate by framing the issues in terms of the public health impacts of climate change. While Macpherson and Valles make valid points concerning a potential role for bioethics in the climate change debate, it is important to recognize that much more than ethical analysis and reflection will be needed to significantly impact public attitudes and government policies.     

Ecological Restoration and Global Climate Change

There is an increasing consensus that global climate change occurs and that potential changes in climate are likely to have important regional consequences for biota and ecosystems. Ecological restoration, including (re)afforestation and rehabilitation of degraded land, is included in the array of potential human responses to climate change. However, the implications of climate change for the broader practice of ecological restoration must be considered. In particular, the usefulness of historical ecosystem conditions as targets and references must be set against the likelihood that restoring these historic ecosystems is unlikely to be easy, or even possible, in the changed biophysical conditions of the future. We suggest that more consideration and debate needs to be directed at the implications of climate change for restoration practice.     

Mineral Nutrition and Plant Growth Response to Climate Change

The limiting factor concept has often been used to describeplant growth responses to altered availability of resources.However, even preliminary experiments, where atmospheric CO₂concentrations and solution mineral concentrations were varied,demonstrated that a more complex concept was required to interpretthe potential effects of climate change and mineral availabilityon plant growth. It is proposed that these resources for plantgrowth may be better viewed as simultaneously limiting. Further,in considering the limitation in plant growth to mineral nutritionit is important to consider both the solution concentrationand the total amount of the individual minerals available tothe plant. Sustaining a positive response to increased CO₂ concentration,for example, requires an increase in plant uptake of the totalamount of minerals. Consequently, it is very difficult to predictthe plant growth response to climate change because of the largeuncertainty about mineral availability. On the one hand, increasedCO₂ concentrations should stimulate nitrogen fixation by bothfree-living organisms and symbiotic systems, and improve soilproperties for mineral availability as a result of increasedorganic matter deposition in the soil. On the other hand, increasedtemperature and altered rainfall patterns may result in increasedlosses of soil minerals. Even the direction in the net changein available soil minerals is unclear. Realistic evaluationsof the effects of climate change on plant growth will be challengedto contend with the large uncertainty and complexities in understandingmineral availability and plant mineral nutrition.     

Coral Reef Habitat Response to Climate Change Scenarios

Coral reef ecosystems are threatened by both climate change and direct anthropogenic stress. Climate change will alter the physico-chemical environment that reefs currently occupy, leaving only limited regions that are conducive to reef habitation. Identifying these regions early may aid conservation efforts and inform decisions to transplant particular coral species or groups. Here a species distribution model (Maxent) is used to describe habitat suitable for coral reef growth. Two climate change scenarios (RCP4.5, RCP8.5) from the National Center for Atmospheric Research’s Community Earth System Model were used with Maxent to determine environmental suitability for corals (order Scleractinia). Environmental input variables best at representing the limits of suitable reef growth regions were isolated using a principal component analysis. Climate-driven changes in suitable habitat depend strongly on the unique region of reefs used to train Maxent. Increased global habitat loss was predicted in both climate projections through the 21^st century. A maximum habitat loss of 43% by 2100 was predicted in RCP4.5 and 82% in RCP8.5. When the model is trained solely with environmental data from the Caribbean/Atlantic, 83% of global habitat was lost by 2100 for RCP4.5 and 88% was lost for RCP8.5. Similarly, global runs trained only with Pacific Ocean reefs estimated that 60% of suitable habitat would be lost by 2100 in RCP4.5 and 90% in RCP8.5. When Maxent was trained solely with Indian Ocean reefs, suitable habitat worldwide increased by 38% in RCP4.5 by 2100 and 28% in RCP8.5 by 2050. Global habitat loss by 2100 was just 10% for RCP8.5. This projection suggests that shallow tropical sites in the Indian Ocean basin experience conditions today that are most similar to future projections of worldwide conditions. Indian Ocean reefs may thus be ideal candidate regions from which to select the best strands of coral for potential re-seeding efforts.     

Response of Pleistocene Coral Reefs to Environmental Change Over Long Temporal Scales

SYNOPSIS. TWO studies from the Pleistocene coral reef fossilrecord demonstrate the sensitivity of reef communities to bothlocal environmental parameters and habitat reduction. In thefirst study, Pleistocene reef coral assemblages from Papua NewGuinea show pronounced constancy in taxonomic composition andspecies diversity between 125 and 30 ka (thousand years). Spatialdifferences in reef coral community composition during successivehigh stands of sea level were greater among sites of the sameage than among reefs of different ages, even though global changesin sea level, atmospheric CO₂ concentration, tropical benthichabitat area, and temperature varied at each high sea levelstand. Thus, local environmental variation associated with runofffrom the land had greater influence on reef coral communitycomposition than variation in global climate and sea level.Proportional sampling from a regional species pool does notexplain the temporal persistence and local factors likely playeda major role. Examination of coral reef response to global changeshould not only involve regional diversity patterns but alsolocal ecological factors, and the interactive effects of localand global environmental change. In the second study, Pleistocene extinction of two widespread,strictly insular species of Caribbean reef corals, Pocilloporacf. palmata (Geister, 1975) and an organ-pipe growth form ofthe Montastraea "annularis" species complex, was natural anddid not involve gradual decrease in range and abundance, butwas sudden (thousands of years) throughout the entire range.One explanation is that sea level drop at the Last Glacial Maximum(LGM—18 ka) resulted in a threshold of habitat reduction,and caused disruption of coral metapopulation structure. Thresholdeffects predicted by metapopulation dynamics may also explainthe apparent paradox of the large amount of degraded modernreef habitat without any known modern-day reef coral extinctions.The rapid extinction of widespread Pleistocene species emphasizesthe vulnerability of reef corals in the face of present rapidenvironmental and climatic change.     

Response of Microbial Community Composition and Function to Soil Climate Change

Soil microbial communities mediate critical ecosystem carbon and nutrient cycles. How microbial communities will respond to changes in vegetation and climate, however, are not well understood. We reciprocally transplanted soil cores from under oak canopies and adjacent open grasslands in a California oak–grassland ecosystem to determine how microbial communities respond to changes in the soil environment and the potential consequences for the cycling of carbon. Every 3 months for up to 2 years, we monitored microbial community composition using phospholipid fatty acid analysis (PLFA), microbial biomass, respiration rates, microbial enzyme activities, and the activity of microbial groups by quantifying ¹³C uptake from a universal substrate (pyruvate) into PLFA biomarkers. Soil in the open grassland experienced higher maximum temperatures and lower soil water content than soil under the oak canopies. Soil microbial communities in soil under oak canopies were more sensitive to environmental change than those in adjacent soil from the open grassland. Oak canopy soil communities changed rapidly when cores were transplanted into the open grassland soil environment, but grassland soil communities did not change when transplanted into the oak canopy environment. Similarly, microbial biomass, enzyme activities, and microbial respiration decreased when microbial communities were transplanted from the oak canopy soils to the grassland environment, but not when the grassland communities were transplanted to the oak canopy environment. These data support the hypothesis that microbial community composition and function is altered when microbes are exposed to new extremes in environmental conditions; that is, environmental conditions outside of their “life history” envelopes.     

亚高山草甸植物群落对气候变化的响应

为了研究气温升高、氮素增加和人为干扰对亚高山草甸植物生长和非结构性碳水化合物(NSC)的影响,该研究采用开顶式生长箱(OTC)模拟增温,同时进行施加氮肥和除草处理,对青藏高原东南缘邛崃山脉东坡巴郎山(四川盆地向青藏高原的过渡地带)的亚高山草甸植物的生长和NSC含量进行测定分析。结果显示:(1)各处理土壤全磷(P)和全钾(K)含量与对照均无显著差异,增温加施肥处理的土壤全氮(N)含量与对照无显著差异,但增温处理、施肥处理、除草处理、增温加除草处理、施肥加除草处理和增温加施肥加除草处理的土壤全氮含量较对照均显著降低。(2)增温促进禾本科和杂类草功能群生长,抑制莎草科功能群生长,提高禾本科功能群重要值,降低杂类草功能群重要值,且对莎草科功能群重要值的作用受施氮和除草的影响;施肥促进禾本科和杂类草功能群的高生长,并且促进莎草科功能群生长;除草促进莎草科功能群生长,抑制禾草科和杂类草功能群的生长;而施肥和除草的交互作用有利于禾草科功能群生长,施肥和除草都提高了莎草科功能群的重要值,降低了禾草科功能群的重要值。(3)不同物种NSC含量及分配对于各处理的响应有所不同,紫地榆的NSC含量与物种分盖度相关性显著,珠芽蓼的NSC含量与物种高度相关性显著。研究表明,气候变暖和土壤氮素增加有利于禾本科和莎草科植物的生长,并使植物改变体内非结构性碳水化合物的分配来抵御环境压力。     

植物对气候变化生理生态响应的不确定性分析

生态系统对全球气候变化的响应模式有利于人类预测与适应未来生态环境变化,植物作为陆地生态系统的重要组成部分,对全球气候变化的响应具有重要作用.本文通过对近年来植物对气候变化的生理生态响应研究中(包括定点控制实验,空间代替时间样带),植物响应模式的复杂性、多样性及可变性等诸多不确定性进行分析.以探讨预测未来气候情景下植物的动态变化及生理生态响应过程.分析结果认为.造成这些不确定性的主要原因包括:(1)利用空间代替时间的样带研究中,往往忽略了植物的非线性响应,存在明显的阈值;(2)样带及定点研究中,由于各种气候因子的耦合.很难确定各种气候因子对植物生理生态学特性影响的权重;(3)定点控制实验中往往忽略了植物对气候变化的适应性,使实验结果很难代表更长时间尺度上的反映模式;(4)在相同的气候变化条件下,不同植物的响应有可能存在明显差异.提出了今后植物对气候变化生理生态响应研究的建议.     

Seasonal Response of Grasslands to Climate Change on the Tibetan Plateau

Background

Monitoring vegetation dynamics and their responses to climate change has been the subject of considerable research. This paper aims to detect change trends in grassland activity on the Tibetan Plateau between 1982 and 2006 and relate these to changes in climate.

Methodology/Principal Findings

Grassland activity was analyzed by evaluating remotely sensed Normalized Difference Vegetation Index (NDVI) data collected at 15-day intervals between 1982 and 2006. The timings of vegetation stages (start of green-up, beginning of the growing season, plant maturity, start of senescence and end of the growing season) were assessed using the NDVI ratio method. Mean NDVI values were determined for major vegetation stages (green-up, fast growth, maturity and senescence). All vegetation variables were linked with datasets of monthly temperature and precipitation, and correlations between variables were established using Partial Least Squares regression. Most parts of the Tibetan Plateau showed significantly increasing temperatures, as well as clear advances in late season phenological stages by several weeks. Rainfall trends and significant long-term changes in early season phenology occurred on small parts of the plateau. Vegetation activity increased significantly for all vegetation stages. Most of these changes were related to increasing temperatures during the growing season and in some cases during the previous winter. Precipitation effects appeared less pronounced. Warming thus appears to have shortened the growing season, while increasing vegetation activity.

Conclusions/Significance

Shortening of the growing season despite a longer thermally favorable period implies that vegetation on the Tibetan Plateau is unable to exploit additional thermal resources availed by climate change. Ecosystem composition may no longer be well attuned to the local temperature regime, which has changed rapidly over the past three decades. This apparent lag of the vegetation assemblage behind changes in climate should be taken into account when projecting the impacts of climate change on ecosystem processes.     

Rapid Response of a Marine Mammal Species to Holocene Climate and Habitat Change

Environmental change drives demographic and evolutionary processes that determine diversity within and among species. Tracking these processes during periods of change reveals mechanisms for the establishment of populations and provides predictive data on response to potential future impacts, including those caused by anthropogenic climate change. Here we show how a highly mobile marine species responded to the gain and loss of new breeding habitat. Southern elephant seal, Mirounga leonina, remains were found along the Victoria Land Coast (VLC) in the Ross Sea, Antarctica, 2,500 km from the nearest extant breeding site on Macquarie Island (MQ). This habitat was released after retreat of the grounded ice sheet in the Ross Sea Embayment 7,500–8,000 cal YBP, and is within the range of modern foraging excursions from the MQ colony. Using ancient mtDNA and coalescent models, we tracked the population dynamics of the now extinct VLC colony and the connectivity between this and extant breeding sites. We found a clear expansion signal in the VLC population ~8,000 YBP, followed by directional migration away from VLC and the loss of diversity at ~1,000 YBP, when sea ice is thought to have expanded. Our data suggest that VLC seals came initially from MQ and that some returned there once the VLC habitat was lost, ~7,000 years later. We track the founder-extinction dynamics of a population from inception to extinction in the context of Holocene climate change and present evidence that an unexpectedly diverse, differentiated breeding population was founded from a distant source population soon after habitat became available.     

秦岭山地植被净初级生产力及对气候变化的响应

基于1999~2009年的NDVI数据和气象数据,利用CASA模型对秦岭山地植被净初级生产力（Net primary productivity,NPP）进行模拟估算,并分析了秦岭NPP的时空变化特征及其对气候变化的响应。结果表明：1999~2009年11年间秦岭山地的平均年NPP为542.24 gC·m^-2·a^-1;研究期内秦岭NPP呈显著增长趋势（P<0.01）,2008年最高（718.77 gC·m^-2·a^-1）,2001年最低（471.78 gC·m^-2·a^-1）;四季对全年NPP的贡献率大小依次为夏季（49.90%）>春季（26.16%）>秋季（18.87%）>冬季（5.07%）;月NPP与温度和降水都显著相关,但与温度的相关性更高,月水平上温度对NPP的影响比降水大;生长季期间NPP与温度和降水的相关性在空间分布上都以正相关为主。     

地-气间碳通量气候响应的模拟研究II.未来气候变化

利用 GCM模式模拟的未来气候状况 ,结合一个简单计算碳通量的模型 ,对未来地 -气间碳交换通量与温度和降水的关系做初步模拟分析。结果显示 ,在未来气候变暖情况下 ,要保持陆地生态系统不成为大气碳源 ,降水量需要有很大的增加幅度 (至少要比 GCM模式模拟的结果要高 )。在不考虑二氧化碳及氮素的“施肥效应”前提下 ,得出要使陆地生态系统的碳通量为零 ,全球平均温度每增加 1℃ ,降水量需要增加 7% (约 5 4 mm)。     

Climate Change and Trophic Response of the Antarctic Bottom Fauna

Background

As Earth warms, temperate and subpolar marine species will increasingly shift their geographic ranges poleward. The endemic shelf fauna of Antarctica is especially vulnerable to climate-mediated biological invasions because cold temperatures currently exclude the durophagous (shell-breaking) predators that structure shallow-benthic communities elsewhere.

Methodology/Principal Findings

We used the Eocene fossil record from Seymour Island, Antarctic Peninsula, to project specifically how global warming will reorganize the nearshore benthos of Antarctica. A long-term cooling trend, which began with a sharp temperature drop ∼41 Ma (million years ago), eliminated durophagous predators—teleosts (modern bony fish), decapod crustaceans (crabs and lobsters) and almost all neoselachian elasmobranchs (modern sharks and rays)—from Antarctic nearshore waters after the Eocene. Even prior to those extinctions, durophagous predators became less active as coastal sea temperatures declined from 41 Ma to the end of the Eocene, ∼33.5 Ma. In response, dense populations of suspension-feeding ophiuroids and crinoids abruptly appeared. Dense aggregations of brachiopods transcended the cooling event with no apparent change in predation pressure, nor were there changes in the frequency of shell-drilling predation on venerid bivalves.

Conclusions/Significance

Rapid warming in the Southern Ocean is now removing the physiological barriers to shell-breaking predators, and crabs are returning to the Antarctic Peninsula. Over the coming decades to centuries, we predict a rapid reversal of the Eocene trends. Increasing predation will reduce or eliminate extant dense populations of suspension-feeding echinoderms from nearshore habitats along the Peninsula while brachiopods will continue to form large populations, and the intensity of shell-drilling predation on infaunal bivalves will not change appreciably. In time the ecological effects of global warming could spread to other portions of the Antarctic coast. The differential responses of faunal components will reduce the endemic character of Antarctic subtidal communities, homogenizing them with nearshore communities at lower latitudes.     

未折叠蛋白应答与疾病的关系

在Ca2 稳态平衡紊乱、葡萄糖饥饿、错误折叠蛋白质的表达、蛋白质糖基化的抑制或胆固醇合成超载等胁迫条件下,会导致内质网内积累大量的未折叠蛋白质,形成内质网应激(endoplasmic reticulum stress,ERS),对细胞产生根本性的危害。在应激条件下,内质网会产生未折叠蛋白应答(unfolded protein responseUPR),通过改变细胞的转录和翻译过程来缓解内质网应激,维持细胞功能;但是,如果细胞长时间处于UPR条件下,则会诱导细胞凋亡。     

乙型肝炎病毒4种基因型与干扰素治疗应答的关系

目的:在细胞水平上比较乙型肝炎病毒(HBV)基因型A,B,C,D对干扰素治疗的不同应答反应,进而探讨基因型对干扰素治疗效果的影响。方法:利用脂质体法将前期构建好的HBV基因型A,B,C,D质粒分别转染入Hep G2细胞系中,并在转染细胞上清中加入干扰素-α2a(IFN-α2a)。ELISA方法用来检测上清中HBV抗原,荧光定量PCR方法检测上清中HBV DNA,通过比较加药前后上清中HBV抗原和DNA水平的变化,反应HBV基因型对IFN-α2a的治疗反应。结果:HBV 4种基因型对IFN-α2a治疗的应答反应存在差异,其中A和B基因型对IFN-α2a的应答明显高于C和D基因型;而基因型A和B之间、以及基因型C和D之间对IFN-α2a的反应无统计学差异。结论:HBV基因型能影响干扰素的治疗效果,其中A和B基因型对IFN-α2a的治疗反应优于C和D基因型,在临床上应开展HBV基因分型检测,用以指导临床用药的选择。