Thermodependent bacterial pathogens and mass mortalities in temperate benthic communities: a new case of emerging disease linked to climate change

In the temperate north-western Mediterranean Sea, large-scale disease outbreaks in benthic invertebrate species have recently occurred during climatic anomalies characterized by elevated seawater temperatures. One of the most affected species was the red gorgonian Paramuricea clavata , a key species of highly diverse communities dwelling in dim-lit habitats in the Mediterranean. From diseased P. clavata colonies, we isolated culturable bacteria associated to tissue lesions in order to investigate their potential as pathogens. Inoculation of four bacterial isolates onto healthy P. clavata in aquaria caused disease signs similar to those observed during the 2003 mortality event. The infection process was dependent on elevated seawater temperatures, in a range of values consistent with recordings performed in the field during the climatic anomalies. Among the four isolates, we identified a Vibrio coralliilyticus strain that showed virulence to P. clavata . This strain was re-isolated from diseased colonies during the experimentations. V. coralliilyticus has been previously identified as a thermodependent pathogen of a tropical coral species, emphasizing a causal role of this infectious agent in the P. clavata disease. Taking into consideration predicted global warming over the coming decades, a better understanding of the factors and mechanisms that affect the disease process will be of critical importance in predicting future threats to temperate gorgonians communities in the Mediterranean Sea.     

Forecasting ecological and evolutionary strategies to global change: an example from habitat selection by lemmings

Ecologists and evolutionary biologists must develop theories that can predict the consequences of global warming and other impacts on Earth's biota. Theories of adaptive habitat selection are particularly promising because they link distribution and density with fitness. The evolutionarily stable strategy that emerges from adaptive habitat choice is given by the system's habitat isodar, the graph of densities in pairs of habitats such that the expectation of fitness is the same in each. We illustrate how isodars can be converted into adaptive landscapes of habitat selection that display the density‐ and frequency‐dependent fitness of competing strategies of habitat use. The adaptive landscape varies with the abundance of habitats and can thus be used to predict future adaptive distributions of individuals under competing scenarios of habitat change. Application of the theory to three species of Arctic rodents living on Herschel Island in the Beaufort Sea predicts changes in selection gradients as xeric upland increases in frequency with global warming. Selection gradients will become more shallow for brown lemming (Lemmus trimucronatus) and tundra vole (Microtus oeconomus) strategies that preferentially exploit mesic habitat. Climate change will cause selection gradients for the alternative strategy of using mostly xeric habitat to become much steeper. Meanwhile, the adaptive landscape for collared lemmings (Dicrostonyx groenlandicus), which specialize on xeric Dryas‐covered upland, will become increasingly convex. Changes in the adaptive landscapes thus predict expanding niches for Lemmus and Microtus, and a narrower niche for Dicrostonyx. The ability to draw adaptive landscapes from current patterns of distribution represents one of the few methods available to forecast the consequences of climate change on the future distribution and evolution of affected species.     

温度对副珠蜡蚧阔柄跳小蜂发育和繁殖的影响

通过观察副珠蜡蚧阔柄跳小蜂Metaphycus parasaissetiae Zhang and Huang在18,21,24,27,30,33和36℃恒温条件下的生长发育情况,求得其世代发育起点温度和世代有效积温分别为13.10℃和215.00日.度,建立世代发育历期预测式为N=[215.00±44.32]/[T-(13.10±3.24)],世代发育速率与温度之间的关系拟合为S形曲线V=-e(1.33+37.73/T),推算出该蜂在海南1年可发生18代。所设试验温度范围内,该蜂对橡副珠蜡蚧Parasaissetia nigra(Nietner)的寄生率在13.33%～20.00%范围内波动,30℃时寄生率最高;雌性比率在27℃时最大为70.03%。随着试验温度的升高,成蜂羽化相对集中,羽化持续时间逐渐缩短,羽化高峰提前。30℃条件下雌蜂终生产卵量最多,平均25.77粒。雌蜂寿命随试验温度的升高而逐渐缩短,同一恒温条件下补充20%蜂蜜水可显著延长雌蜂寿命。27～30℃可视为有利于副珠蜡蚧阔柄跳小蜂发育繁殖的适温范围,最适温度为30℃。     

Potential effects of interaction between CO2 and temperature on forest landscape response to global warming

Projected temperature increases under global warming could benefit southern tree species by providing them the optimal growing temperature and could be detrimental to northern species by exposing them to the supra optimal growing temperatures. This benefit-detriment trade-off could increase the competitive advantage of southern species in the northern species range and cause the increase or even dominance of southern species in the northern domain. However, the optimum temperature for photosynthesis of C3 plants may increase due to CO₂ enrichment. An increase in the optimum temperature could greatly reduce the benefit-detriment effect. In this study, we coupled a forest ecosystem process model (PnET-II) and a forest GAP model (LINKAGES) with a spatially dynamic forest landscape model (LANDIS-II) to study how an optimum temperature increase could affect forest landscape response due to global warming. We simulated 360 years of forest landscape change in the Boundary Water Canoe Area (BWCA) in northern Minnesota, which is transitional between boreal and temperate forest. Our results showed that, under the control scenario of continuing the historic 1984–1993 mean climate (mainly temperature, precipitation and CO₂), the BWCA will become a spruce-fir dominated boreal forest. However, under the scenario of predicted climatic change [the 2000–2099 climates are predicted by Canadian Climate Center (CCC), followed by 200 years of continuing the predicted 2090–2099 mean climate], the BWCA will become a pine-dominated mixed forest. If the optimum temperature increases gradually with [CO₂] (the increase in optimum temperature is assumed to change gradually from 0 °C in year 2000 to 5 °C in year 2099 when [CO₂] reaches 711 ppm and stabilizes at 5 °C after year 2099), the BWCA would remain a fir-dominated boreal forest in areas with relatively high water-holding capacity, but not in areas with relatively low water-holding capacity. Our results suggest that the [CO₂] induced increases in optimum temperature could substantially reduce forest landscape change caused by global warming. However, not all tree species would be able to successfully adapt to future warming as predicted by CCC, regardless of optimum temperature acclimations.     

New insight on spatial localization and microstructures of calcite-aragonite interfaces in adult shell of Haliotis tuberculata: Investigations of wild and farmed abalones by FTIR and Raman mapping

In the present study, we investigated the shell microstructures of the gastropod European abalone Haliotis tuberculata in order to clarify the complex spatial distribution of the different mineral phases. Our studies were carried out with a standardized methodology on thirty adult European abalone H. tuberculata (5–6 cm long) composed of 15 wild individuals and 15 individuals taken from the France Haliotis hatchery. The macroscopic (binocular) and microscopic observations coupled with Fourier Transform Infrared Spectroscopy (FTIR) and Raman vibrational analysis allowed to unambiguously detect, identify and localize calcite and aragonite. For the first time it has been shown that calcite is present in 100% of farmed and wild adult shell. The microstructural details of the calcite-aragonite interfaces were revealed by using both confocal micro-Raman mapping and Scanning Electron Microscopy (SEM) observations. Calcite zones are systematically found in the spherulitic layer without direct contact with the nacreous layer. The calcite area - nacreous layer interface is made of a thin spherulitic layer with variable thickness from a few micrometers to several millimeters.In order to contribute to a better understanding of the biomineralization process, a model explaining the hierarchical arrangement of the different phases of calcium carbonate is presented and discussed. Finally, it has been shown that these calcitic zones can be connected to each other within the shells and that their spatial distributions correspond to streaks perpendicular to the direction of length growth.     

温度对咖啡豆象实验种群发育和繁殖的影响

为探讨温度对咖啡豆象Araecerus fasciculatus实验种群生长发育和繁殖参数的影响, 以及昆虫生命活动与环境因子之间的关系, 为其种群数量控制提供依据, 本研究在17, 20, 23, 26, 29和32℃下, 研究咖啡豆象各虫态的发育与繁殖; 用线性回归、Logistic模型及“王-兰-丁”模型对温度与咖啡豆象各虫态之间的数学关系进行拟合; 通过最小二乘法计算了咖啡豆象的发育起点温度和有效积温。结果表明: 17~29℃之间, 随着温度的升高, 咖啡豆象幼虫的发育速率逐渐增大, 至32℃, 发育速率稍微降低。温度为27.43℃时, 咖啡豆象幼虫有理论最大发育速率0.493 d^-1。卵、幼虫、蛹和卵-蛹期的发育起点温度分别为9.60, 11.48, 7.60和10.55℃, 有效积温分别为135.51, 523.57, 157.09和828.63日度。温度对咖啡豆象实验种群发育和繁殖有显著影响, 发育起点温度和有效积温较低是该虫危害严重的主要原因之一。本研究拟合数学模型可为该害虫的发生危害预测及综合管理提供技术支撑。     

Influence of nutrition on disease development caused by fungal pathogens: implications for plant disease control

A great deal of information is available in the literature on the effects of nutrition on disease development in plants and crops. However, much of this information is contradictory and although it is widely recognised that nutrition can influence disease in crops, limited progress has been made in the manipulation of crop nutrition to enhance disease control. Achieving this aim requires a sound understanding of the effects of fertilisation on nutrient levels and availability in crop tissues, and in turn, how the nutrient status of such tissues influences pathogen infection, colonisation and sporulation. Some of these details are known for a number of crop plants under controlled conditions, but very little of this type of information is available for crops under field conditions. This review focuses on nitrogen, sulphur, phosphorus, potassium and silicon, examines the availability of these nutrients in plant tissues to support pathogen growth and development, and reviews the effects of the different nutrients on disease development. The review also examines the potential for manipulating crop nutrition to enhance disease control in conventional and organic cropping systems.     

An experimental test of the role of environmental temperature variability on ectotherm molecular, physiological and life-history traits: implications for global warming

Global climate change is one of the greatest threats to biodiversity; one of the most important effects is the increase in the mean earth surface temperature. However, another but poorly studied main characteristic of global change appears to be an increase in temperature variability. Most of the current analyses of global change have focused on mean values, paying less attention to the role of the fluctuations of environmental variables. We experimentally tested the effects of environmental temperature variability on characteristics associated to the fitness (body mass balance, growth rate, and survival), metabolic rate (VCO(2)) and molecular traits (heat shock protein expression, Hsp70), in an ectotherm, the terrestrial woodlouse Porcellio laevis. Our general hypotheses are that higher values of thermal amplitude may directly affect life-history traits, increasing metabolic cost and stress responses. At first, results supported our hypotheses showing a diversity of responses among characters to the experimental thermal treatments. We emphasize that knowledge about the cellular and physiological mechanisms by which animals cope with environmental changes is essential to understand the impact of mean climatic change and variability. Also, we consider that the studies that only incorporate only mean temperatures to predict the life-history, ecological and evolutionary impact of global temperature changes present important problems to predict the diversity of responses of the organism. This is because the analysis ignores the complexity and details of the molecular and physiological processes by which animals cope with environmental variability, as well as the life-history and demographic consequences of such variability.     

Influence of temperature and size of females on the timing of spawning of perch,Perca fluviatilis,in Lake Geneva from 1984 to 1993

Synopsis The influence of temperature and the size of reproducing females on the timing of spawning of perch in Lake Geneva has been studied for 10 consecutive years (1984–1993) by means of artificial spawning substrates. The clutch of perch is an egg ribbon with a width proportional to the size of the reproducing female, so that the size structure distribution of the female population can be estimated from measurements of the width of the egg ribbons. The survey of egg-ribbon size revealed a succession of 3 cycles (period of increasing mean size followed by a sharp decrease) lasting 3, 3 and 4 years which were due to the occurrence of 3 strong year classes born in 1982, 1985 and 1988 respectively. This phenomenon can be explained by the effect of intraspecific predation exerted by strong year classes on the offspring of the 2 following years rather than by fluctuations in the success of reproduction in relation to climatic changes. In Lake Geneva, perch spawn in May. The water temperature exerted only a minor influence on the date of the beginning of the spawning period but had a greater effect on its intensity. A rise in temperature in May stimulated spawning while bad weather decreased spawning intensity. The larger perch had a tendency to spawn later than the small ones. The date of the mid-spawning period was well correlated with the yearly mean width of perch egg ribbons but no correlation could be detected between it and the water temperature.     

维生素E对暴露于高温及PM2.5中COPD大鼠呼吸系统的保护性作用*

目的:探讨维生素E改善暴露于高温与PM_2.5对慢性阻塞性肺疾病(COPD)大鼠呼吸系统功能损伤的作用。方法:将54只7周龄SPF级雄性Wistar大鼠随机分成9个实验组(n=6),利用烟草烟雾和气管内滴注脂多糖建立COPD大鼠模型,而后对其进行PM_2.5(0 mg/ml、3.2 mg/ml)气管滴注染毒和维生素E腹腔注射(20 mg/ml)干预,随后高温组进行高温(40℃)暴露,每天一次(8 h),持续3 d。末次暴露后检测肺功能,HE染色制作肺组织病理切片,采用试剂盒测定大鼠肺组织中诱导性一氧化氮合酶(iNOS)、肿瘤坏死因子(TNF-α)、单核细胞趋化蛋白1(MCP-1)的表达水平。结果:与对照组相比,高温和PM_2.5暴露使COPD大鼠肺功能降低(P＜0.05),各PM_2.5染毒组中MCP-1含量均有显著升高(P＜0.05),高温组中iNOS活性显著增高(P＜0.05);与单纯PM_2.5染毒组相比,在常温健康和高温COPD维生素E干预组的TNF-α含量均显著降低(P＜0.05),三组维生素干预组中MCP-1含量均显著降低(P＜0.05),高温COPD维生素干预组中iNOS活性显著降低(P＜0.05)。结论:高温与PM_2.5可引起并进一步加重COPD大鼠的炎症反应,维生素E作为一种抗氧化剂,可明显改善上述损伤作用,从而保护机体。     

温度对马铃薯甲虫生长发育的影响

为了进一步明确温度对马铃薯甲虫Leptinotarsa decemlineata (Say)生长发育的影响, 在恒温条件, 研究了温度对马铃薯甲虫实验种群生长发育的影响。结果表明：温度对马铃薯甲虫各虫态的发育历期、存活率及种群的繁殖力有显著的影响。发育历期随温度的升高而缩短, 发育速率与温度呈显著的正相关。马铃薯甲虫世代存活率由大到小的顺序为27℃＞23℃＞19℃＞31℃＞15℃。27℃时成虫的产卵量最高, 单雌平均卵量为729.7粒;其次为23℃, 单雌平均卵量为639.2粒。并测得马铃薯甲虫卵、1龄幼虫、2龄幼虫、3龄幼虫、4龄幼虫、幼虫期、蛹期及全世代的发育起点温度分别为9.14, 10.50, 8.17, 10.28, 9.04, 9.59, 10.23和10.90℃, 有效积温分别为73.26, 43.22, 39.23, 34.05, 161.97, 273.02, 100.38和542.58日·度。据此认为温度对马铃薯甲虫实验种群的生长发育、存活和繁殖影响明显。     

Effects of temperature and ultraviolet radiation on microbial foodweb structure: potential responses to global change

1. A series of growth experiments were conducted with natural plankton communities from a lake and river in northern Quebec, to evaluate the response of microbial foodweb structure to changes in ambient temperature and solar ultraviolet radiation (UVR). 2. Bioassays were incubated for 6 days at two temperatures (10 and 20 °C) and three near-surface irradiance conditions [photosynthetically active radiation (PAR) + UVA + UVB, PAR + UVA, and PAR only). 3. The concentration of total bacteria showed no net response to temperature, but the percentage of actively respiring bacteria, as measured with the cellular redox probe 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), was up to 57% higher at 20 °C relative to 10 °C. Chlorophyll a concentrations in the < 2 μm size fraction also reacted strongly to temperature, with a net increase of up to 61% over the temperature range of 10–20 °C. 4. The UVR effects were small or undetectable for most of the measured variables; however, the percentage of actively respiring bacteria was significantly inhibited in the presence of UVR at 20 °C, decreasing by 29–48% on day 6 in the lake experiments and by 59% on day 2 in one river experiment. 5. The results show differential sensitivity to temperature among organisms of microbial communities in subarctic freshwaters, and a resilience by the majority of micro-organisms to their present UVR conditions. Microbial foodwebs in northern freshwaters appear to be relatively unresponsive to short-term (days) changes in UVR. However, the observed responses to temperature suggest that climate change could influence community structure, with warmer temperatures favouring picoplanktonic phototrophs and heterotrophs, and a shift in nanoplankton species composition and size structure.     

温度对白蜡吉丁柄腹茧蜂发育和繁殖的影响

为了提高白蜡窄吉丁Agrilus planipennis的重要天敌——白蜡吉丁柄腹茧蜂Spathius agrili Yang的繁育效率, 本研究调查了不同温度（22, 24, 26, 28, 30和32℃）对该蜂生长发育及繁殖的影响。结果表明, 在22~32℃范围内, 白蜡吉丁柄腹茧蜂的卵、茧蛹及世代发育速率均随着温度的升高而加快, 而幼虫的发育速率在26℃时最快. 卵、幼虫、茧蛹和世代的发育起点温度分别为14.34, 16.89, 14.16和13.84℃, 有效积温分别为24.59, 61.16, 166.27和276.80日·度。温度对白蜡吉丁柄腹茧蜂的寄生率、寄生成功率、产卵量、子代蜂数量和性比都有不同程度的影响。据此提出适于人工繁育白蜡吉丁柄腹茧蜂的温度范围为26~28℃。     

A test for constant fatality rate of an emerging epidemic: with applications to severe acute respiratory syndrome in Hong Kong and Beijing

Summary .   The etiology, pathogenesis, and prognosis for a newly emerging disease are generally unknown to clinicians. Effective interventions and treatments at the earliest possible times are warranted to suppress the fatality of the disease to a minimum, and inappropriate treatments should be abolished. In this situation, the ability to extract most information out of the data available is critical so that important decisions can be made. Ineffectiveness of the treatment can be reflected by a constant fatality over time while effective treatment normally leads to a decreasing fatality rate. A statistical test for constant fatality over time is proposed in this article. The proposed statistic is shown to converge to a Brownian motion asymptotically under the null hypothesis. With the special features of the Brownian motion, we are able to analyze the first passage time distribution based on a sequential tests approach. This allows the null hypothesis of constant fatality rate to be rejected at the earliest possible time when adequate statistical evidence accumulates. Simulation studies show that the performance of the proposed test is good and it is extremely sensitive in picking up decreasing fatality rate. The proposed test is applied to the severe acute respiratory syndrome data in Hong Kong and Beijing.     

杨树球二孢溃疡病的研究—生物学特性、发病规律及药剂筛选

经试验,杨树球二孢溃疡病菌(Botryodiplodia populea Z.K.Zhong)适宜生长温度为20—25℃,pH6—7,在PDA和麦芽粉培养基生长良好。该病于4月中下旬产生病斑,5月上旬呈现颗粒状的子实体,5月中旬以后逐渐成熟开裂,溢出炭黑色的分生孢子,病原菌以菌丝体在树皮内越冬。经室内药剂筛选,660B生物农药抑菌效果最佳,可达95%。     

Integrating spatial data and shorebird nesting locations to predict the potential future impact of global warming on coastal habitats: A case study on Farasan Islands,Saudi Arabia

One of the expected effects of the global warming is changing coastal habitats by accelerating the rate of sea level rise. Coastal habitats support large number of marine and wetland species including shorebirds (plovers, sandpipers and allies). In this study, we investigate how coastal habitats may be impacted by sea level rise in the Farasan Islands, Kingdom of Saudi Arabia. We use Kentish plover Charadrius alexandrinus – a common coastal breeding shorebird – as an ecological model species to predict the influence of sea level rise. We found that any rise of sea level is likely to inundate 11% of Kentish plover nests. In addition, 5% of the coastal areas of Farasan Islands, which support 26% of Kentish plover nests, will be flooded, if sea level rises by one metre. Our results are constrained by the availability of data on both elevation and bird populations. Therefore, we recommend follow-up studies to model the impacts of sea level rise using different elevation scenarios, and the establishment of a monitoring programme for breeding shorebirds and seabirds in Farasan Islands to assess the impact of climate change on their populations.     

短时高温暴露对土耳其斯坦叶螨和截形叶螨的影响

【目的】为了明确土耳其斯坦叶螨Tetranychus turkestani和截形叶螨T. truncatus在高温逆境下的生存特性对其种群发展的影响。【方法】通过短时高温处理试验, 研究了土耳其斯坦叶螨和截形叶螨卵、 幼螨、 成螨在38℃, 42℃和46℃下处理2～6 h后的孵化率和存活率, 以及对其后续发育历期和生殖的影响。【结果】两种叶螨的卵和幼螨在38～46℃下处理2～6 h, 其存活率随着温度和处理时间的增加而降低, 后续发育历期随着温度和处理时间的增加而延长。两种叶螨的雌成螨在38～46℃下处理2～6 h后其存活率、 产卵前期、 产卵期和产卵量均不受影响, 但所产卵的孵化率明显降低, 其中土耳其斯坦叶螨在46℃下处理6 h的孵化率下降了15.5%, 截形叶螨在46℃下处理6 h的孵化率下降了18.0%。【结论】高温暴露主要影响叶螨的孵化率、 存活率和后续的发育历期, 对成螨的寿命和生殖无显著影响; 土耳其斯坦叶螨和截形叶螨对极端高温的适应性存在差异, 土耳其斯坦叶螨对高温的适应性要高于截形叶螨。