Divergent pheromone-mediated insect behaviour under global atmospheric change

While the effects of global atmospheric changes on vegetation and resulting insect populations(‘bottom‐up interactions’) are being increasingly studied, how these gases modify interactions among insects and their natural enemies (‘top‐down interactions’) is less clear. As natural enemy efficacy is governed largely by behavioural mechanisms, altered prey finding and prey defence may change insect population dynamics. Here we show that pheromone‐mediated escape behaviours, and hence the vulnerability of insects to natural enemies, are divergent under atmospheric conditions associated with global climate change. Chaitophorus stevensis, a common aphid on trembling aspen trees, Populus tremuloides, have diminished escape responses in enriched carbon dioxide (CO₂) environments, while those in enriched ozone (O₃) have augmented escape responses, to alarm pheromone. These results suggest that divergent pheromone‐mediated behaviours could alter predator–prey interactions in future environments.     

Root responses along a subambient to elevated CO2 gradient in a C3–C4 grassland

Atmospheric CO₂ (C_a) concentration has increased significantly during the last 20 000 years, and is projected to double this century. Despite the importance of belowground processes in the global carbon cycle, community‐level and single species root responses to rising C_a are not well understood. We measured net community root biomass over 3 years using ingrowth cores in a natural C₃–C₄ grassland exposed to a gradient of C_a from preglacial to future levels (230–550 μmol mol^?1). Root windows and minirhizotron tubes were installed below naturally occurring stands of the C₄ perennial grass Bothriochloa ischaemum and its roots were measured for respiration, carbohydrate concentration, specific root length (SRL), production, and lifespan over 2 years. Community root biomass increased significantly (P<0.05) with C_a over initial conditions, with linear or curvilinear responses depending on sample date. In contrast, B. ischaemum produced significantly more roots at subambient than elevated C_a in minirhizotrons. The lifespan of roots with five or more neighboring roots in minirhizotron windows decreased significantly at high C_a, suggesting that after dense root growth depletes soil resource patches, plants with carbon surpluses readily shed these roots. Root respiration in B. ischaemum showed a curvilinear response to C_a under moist conditions in June 2000, with the lowest rates at C_a<300 μmol mol^?1 and peak activity at 450 μmol mol^?1 in a quadratic model. B. ischaemum roots at subambient C_a had higher SRLs and slightly higher carbohydrate concentrations than those at higher C_a, which may be related to drier soils at low C_a. Our data emphasize that belowground responses of plant communities to C_a can be quite different from those of the individual species, and suggest that complex interactions between and among roots and their immediate soil environment influence the responses of root physiology and lifespan to changing C_a.     

Quantitation of ceramides in nude mouse skin by normal-phase liquid chromatography and atmospheric pressure chemical ionization mass spectrometry

A sensitive and accurate normal-phase liquid chromatography and atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) method for determining the standard ceramide [NS] (Cer[NS]) was developed and validated so as to improve the traditional thin-layer chromatography (TLC) technique and LC-electrospray ionization (ESI)-MS method to profile and quantify ceramides in nude mouse skin. Normal-phase LC-APCI-MS was optimized to separate the nine classes of ceramides presented in the stratum corneum (SC) of nude mouse skin. A normal-phase silica column eluted with the gradient system from heptane:acetone/butanol (90:10, v/v) of 75:25 to 100% acetone/butanol (90:10, v/v) (with each solvent containing 0.1% [v/v] triethylamine and 0.1% [v/v] formic acid) at a flow rate of 0.8 ml/min was found to be optimal for analyzing standard Cer[NS]. The analysis of Cer[NS] was validated and employed as the standard for constructing a calibration curve to quantitate all classes of ceramides. This method was applied to profile the classes and contents of ceramides in the SC of nude mouse skin and proved to be workable. It was concluded that this improved method can be used to directly detect and quantify all classes of ceramides in the SC of nude mouse skin and that it is more convenient and labor-saving than the traditional TLC method.     

豚鼠膀胱灌注卡介苗后的毒性研究

为观察治疗用BCG对豚鼠膀胱所产生的毒性反应和中毒程度 ,确定中毒靶向器官 ,以BCG12mg/kg .3d和36 0mg/kg .3d两个剂量对雌性豚鼠进行膀胱灌注 ,连续 3个月 ,共计 2 8次。结果显示BCG可明显引起豚鼠膀胱炎症反应 ,血中性粒细胞含量增多和尿素氮值升高。所有异常指标在用药后 1个月内基本恢复正常 ,提示治疗用BCG是一种安全、低毒的生物制品 ,为临床安全用药提供了依据     

Scale Interactions and Regional Climate: Examples from the Susquehanna River Basin

One of the most difficult problems faced by climatologists is how to translate global climate model (GCM) output into regional- and local-scale information that health and environmental effects researchers can use. It will be decades before GCMs will be able to resolve scales small enough for most effects research, so climatologists have developed climate downscaling methods to bridge the gap between the global and local scales. There are two main streams of climate downscaling research. First, high-resolution, limited-area climate models can be embedded in the coarse-scale GCMs, producing much finer resolution climate data. Second, empirical downscaling techniques develop transfer functions linking the large-scale atmospheric circulation generated by the GCMs to surface data. Examples of both types of downscaling, aimed at improving projections of future climate in the Susquehanna River Basin (the Mid-Atlantic Region of the United States), are presented. A third case is also described in which an even higher-resolution nested atmospheric model is being developed and linked to a hydrologic model system, with the ultimate goal of simulating the environmental response to climate forcing at all time and space scales.     

The effect of typhoons on POPs in atmospheric particulates over the coastal islands of Fujian,southeast China

Abstract

Atmospheric particulate samples were collected during three typhoons in 2006 (Chanchu, Bilis, and Kaemi) from Dongshan and Pingtan Islands along the coastal areas of Fujian Province and were analyzed for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The observations were divided into three periods, namely, pre-typhoon, typhoon, and post-typhoon, to analyze the variations in POP concentrations. The results showed that the PCB and OCP concentrations had daily variations during the pre-typhoon period, while different variation trends were observed during the typhoon periods. The concentrations of those contaminants increased dramatically during typhoon Chanchu (the total concentrations of PCBs and OCPs increased 25 and 24 times, respectively), whereas those values decreased slightly during the typhoon Bilis and Kaemi. However, POPs levels all decreased noticeably during the three post-typhoon periods due to heavy rainfall caused by the typhoons. Observations of an ensemble of factors, including the typhoon migration routes, landfall season, air mass origins and meteorological conditions, and the typhoon migration route was the dominant factor to cause high levels of POPs during the typhoon Chanchu period. Toxicity assessment indicated that the effect of PCB and OCP during the typhoon period should be a concern, which could pose a high potential health risk to organisms.     

Commuting fruit bats beneficially modulate their flight in relation to wind

When animals move, their tracks may be strongly influenced by the motion of air or water, and this may affect the speed, energetics and prospects of the journey. Flying organisms, such as bats, may thus benefit from modifying their flight in response to the wind vector. Yet, practical difficulties have so far limited the understanding of this response for free-ranging bats. We tracked nine straw-coloured fruit bats (Eidolon helvum) that flew 42.5 ± 17.5 km (mean ± s.d.) to and from their roost near Accra, Ghana. Following detailed atmospheric simulations, we found that bats compensated for wind drift, as predicted under constant winds, and decreased their airspeed in response to tailwind assistance such that their groundspeed remained nearly constant. In addition, bats increased their airspeed with increasing crosswind speed. Overall, bats modulated their airspeed in relation to wind speed at different wind directions in a manner predicted by a two-dimensional optimal movement model. We conclude that sophisticated behavioural mechanisms to minimize the cost of transport under various wind conditions have evolved in bats. The bats’ response to the wind is similar to that reported for migratory birds and insects, suggesting convergent evolution of flight behaviours in volant organisms.     

大气湿沉降油菜体内铅的形态累积及氧化胁迫效应

大气沉降是叶菜类农作物可食部位重金属铅（Pb）累积的主要来源，但大气湿沉降下铅在油菜（Brassica chinensis L.）体内的形态累积特征及氧化胁迫效应，尚不十分清晰。通过模拟大气湿沉降铅胁迫，研究油菜体内重金属Pb的累积、亚细胞分布、化学形态特征及油菜抗氧化响应。结果表明，油菜可食部位Pb含量为1.72-6.35 mg/kg，超出标准（GB 2762-2017）4.73-20.16倍。Pb大量分布在油菜茎和叶的细胞壁中（52.14%-86.99%），以草酸盐沉淀的形式存在（20.07%-59.27%），这可能会导致Pb在可食部位的大量累积（>95%）。细胞壁的固持作用和Pb主要以草酸盐和不溶性磷酸盐存在，可能是油菜重要的解毒耐性机制之一。湿沉降铅胁迫可以增加叶和茎的丙二醛（MDA）含量，造成细胞的氧化损伤，抑制叶绿素的合成。油菜可以通过提高抗氧化酶（SOD、POD、CAT）活性（7.73%-346.91%），增加抗氧化剂（AsA和GSH）和可溶性物质（可溶性糖、可溶性蛋白）含量（9.11%-279.59%），来有效应对湿沉降Pb胁迫。抗氧化酶在叶中变化最大，过氧化物酶（POD）和过氧化氢酶（CAT）活性分别上升49.41%-91.62%和123.42%-346.91%。抗氧化剂则在根中变化最显著，抗坏血酸（AsA）和谷胱甘肽（GSH）含量分别上升了134.15%-182.93%和238.78%-279.59%。可溶性糖、可溶性蛋白、POD、CAT和GSH可能是油菜叶能缓解湿沉降Pb氧化胁迫的主要因素之一（P<0.05）。研究结果可加深对大气沉降下Pb在叶菜体内累积分布行为的理解，并为大气重金属胁迫地区农作物重金属风险评估提供一定的理论依据。     

Elemental composition of ambient air particles in Taiyuan,China: evaluation of lifetime cancer and non-cancer risks

Abstract

Shanxi is a heavily polluted area in China. Our aim was to analyze the elemental concentration (71 elements) in ambient air in Taiyuan and evaluate cancer and non-cancer risks. Air was sampled in four urban sites and one rural site in the heating season (winter/spring) and summer season (totally 118?days sampling time). Mean total suspended particles (TSP) across all sampling sites were 248 µg/m³ in summer and 478 µg/m³ in winter. The heating season had higher levels of S, Pb, Br, Mn, Se, As, Ni, Cd, and Hg (23.3 µg/m³, 821?ng/m³, 725?ng/m³, 460?ng/m³, 79?ng/m³, 65?ng/m³, 34?ng/m³, 17?ng/m³, and 3.5?ng/m³, respectively) than the summer season (9.6 µg/m³, 276?ng/m³, 138?ng/m³, 283?ng/m³, 0?ng/m³, 21?ng/m³, 21?ng/m³, 6.8?ng/m³, and 0?ng/m³, respectively), except for Cr and Co, of which the levels were higher in summer. Many elements had a high correlation with the TSP level (r?=?0.70–0.96) and S (r?=?0.61–0.95). A health risk assessment demonstrated that Mn and Cr could have a risk of non-cancer effects. Estimated lifetime cancer risks (R_i>10^?6) were observed for As, Cd, Co, Cr, and Ni, indicating that cancer risks from air pollution were relatively high in Taiyuan.