Exploring the utility of extracellular vesicles in ameliorating viral infection-associated inflammation,cytokine storm and tissue damage

Extracellular vesicles (EVs) have emerged as potential mediators of intercellular communication. EVs are nano-sized, lipid membrane–bound vesicles that contains biological information in the form of proteins, metabolites and/or nucleic acids. EVs are key regulators of tissue repair mechanisms, such as in the context of lung injuries. Recent studies suggest that EVs have the ability to repair COVID19-associated acute lung damage. EVs hold great promise for therapeutic treatments, particularly in treating a potentially fatal autoimmune response and attenuate inflammation. They are known to boost lung immunity and are involved in the pathogenesis of various lung diseases, including viral infection. EV-based immunization technology has been proven to elicit robust immune responses in many models of infectious disease, including COVID-19. The field of EV research has tremendous potential in advancing our understanding about viral infection pathogenesis, and can be translated into anti-viral therapeutic strategies.     

Impact of storm‐burning on Melaleuca viridiflora invasion of grasslands and grassy woodlands on Cape York Peninsula,Australia

This paper examines invasion of grasslands on Cape York Peninsula, Australia, by Melaleuca viridiflora and other woody species, and the role of storm‐burning (lighting fires after the first wet season rains) in their maintenance. Trends in disturbance features, fuel characteristics, ground layer composition, and woody plants dynamics under combinations of withholding fire and storm‐burning over a 3‐year period were measured on 19 plots in three landscape settings. Population dynamics of M. viridiflora are described in detail and 20‐year population projections based on transition matrices under different fire regimes generated. Numerous M. viridiflora suckers occurred within the grass layer, increasing each year regardless of fire regime, and were rapidly recruited to the canopy in the absence of fire. Storm‐burning had little impact on fuel, ground layer or woody plant composition, but maintained open vegetation structure by substantially reducing recruitment of M. viridiflora suckers to the sapling layer, and by reducing the above‐grass‐layer abundance of several other invasive woody species. Population projections indicated that withholding fire for 20 years could cause a sevenfold increase of M. viridiflora density on Ti‐tree flats, and that annual to triennial storm‐burning should be effective at maintaining a stable open vegetation structure. These findings argue against vegetation thickening being an inevitable consequence of climate change. We conclude that a fire regime that includes regular storm‐burning can be effective for maintaining grasslands and grassy woodlands being invaded by M. viridiflora.     

绿色屋顶径流氮磷浓度分布及赋存形态

为了解绿色屋顶暴雨径流的氮磷浓度分布及赋存形态,在重庆大学构建了两种绿色屋顶,于2009年9月至2011年10月期间进行了绿色屋顶和对照屋面的暴雨径流水质监测。研究结果表明,绿色屋顶暴雨径流pH值在7.7左右,氨氮浓度满足地表水环境质量标准Ⅲ类标准;总氮、总磷、硝酸根的平均浓度分别为3.6—4.4 mg/L、0.17—0.28 mg/L和3.1—3.7 mg/L,均高于降雨雨水浓度;与对照屋面暴雨径流相比,同时期的绿色屋顶暴雨径流中总氮、氨氮和总磷浓度较低,而硝酸根、磷酸根浓度较高。绿色屋顶暴雨径流水质的季节差异明显,夏季污染物浓度较低,而春秋季节污染物浓度较高;总体上看,随绿色屋顶运行时间的延长,暴雨径流中总氮和硝酸根浓度逐渐降低,而总磷和磷酸盐浓度则呈现出一定的波动性。气象因素、降雨雨水水质与绿色屋顶暴雨径流水质的相关性分析表明,气温越高、前期干旱时间越长,越有利于绿色屋顶径流中氨氮浓度的降低;绿色屋顶径流中的总磷和氨氮主要来自降雨。研究结果为绿色屋顶的科学构建和城市暴雨径流管理提供了重要参考。     

Population genetic structure and long-distance dispersal among seabird populations: implications for colony persistence

Dramatic local population decline brought about by anthropogenic-driven change is an increasingly common threat to biodiversity. Seabird life history traits make them particularly vulnerable to such change; therefore, understanding population connectivity and dispersal dynamics is vital for successful management. Our study used a 357-base pair mitochondrial control region locus sequenced for 103 individuals and 18 nuclear microsatellite loci genotyped for 245 individuals to investigate population structure in the Atlantic and Pacific populations of the pelagic seabird, Leach's storm-petrel Oceanodroma leucorhoa leucorhoa. This species is under intense predation pressure at one regionally important colony on St Kilda, Scotland, where a disparity between population decline and predation rates hints at immigration from other large colonies. AMOVA, F(ST), Φ(ST) and Bayesian cluster analyses revealed no genetic structure among Atlantic colonies (Global Φ(ST) = -0.02 P > 0.05, Global F(ST) = 0.003, P > 0.05, STRUCTURE K = 1), consistent with either contemporary gene flow or strong historical association within the ocean basin. The Pacific and Atlantic populations are genetically distinct (Global Φ(ST) = 0.32 P < 0.0001, Global F(ST) = 0.04, P < 0.0001, STRUCTURE K = 2), but evidence for interocean exchange was found with individual exclusion/assignment and population coalescent analyses. These findings highlight the importance of conserving multiple colonies at a number of different sites and suggest that management of this seabird may be best viewed at an oceanic scale. Moreover, our study provides an illustration of how long-distance movement may ameliorate the potentially deleterious impacts of localized environmental change, although direct measures of dispersal are still required to better understand this process.     

山东半岛滨海沙滩前缘的野生植物

滨海沙滩是以海水影响为基本过程的地貌类型,适应这种环境的植物类群与适生于内陆的沙地植物可能存在巨大差别。在野外调查的基础上,分析了山东半岛滨海沙滩前缘的植物种类及其种间关系。结果表明：（1）滨海沙滩前缘具有独特的优势种库,包括沙钻苔草（Carex kobomugi）、肾叶打碗花（Calystegia soldanella）、粗毛鸭嘴草（Ischaemum bartatum）、单叶蔓荆（Vitex trifolia var.simplicifolia）、矮生苔草（Carex pumila）和沙引草（Messerschmidia sibirica）等;（2）优势种库的成员都是潜在优势种,它们之间主要呈抑制效应,对库外物种几乎没有抑制效应,甚至有互补或互利效应。在进化过程中,这些潜在优势种可能已适应风暴潮的干扰,不会因受风暴潮灾害而灭亡。当植物适应风暴潮后,滨海沙滩不再是灾难环境,反而变为适宜生境。为持续利用这些物种,不仅要保护其赖以生存的天然生境,还要开展引种栽培,消除人们对野生资源的采挖动机。根据物种间的天然联系,栽培时宜将具有互利或互补关系的物种间混种植,不宜将具有抑制关系的物种间混种植。     

Effects of the occurrence of a cyclone and the dominance of a bamboo species on the dynamics of subtropical forest fragments

With the intensification of global warming, the occurrence of large‐scale natural events is becoming even more common in tropical regions, which can impact the structure of plant communities. In this study, we evaluated the isolated and combined effects of an extratropical cyclone and the dominance of a native bamboo species (Merostachys skvortzovii) on floristic composition, diversity, demographic rates and the increment of trees in Atlantic Forest fragments in Southern Brazil. In 2014 (T1) and 2016 (T2), we sampled 56 plots of 200 m² for the effects of an extratropical cyclone in 2009 (T0). We also evaluated another 60 plots of the same size not in the direct path of this cyclone. Half of the plots in each group were covered by dense groupings of bamboos, as a result of past human activities, which could potentially limit natural regeneration. We observed an increase in richness and diversity indices (H′ and 1/D) from the first (T0) to the following assessments (T1 an T2) on the sites affected by the cyclone, when compared to non‐affected sites. After the cyclone, both density and basal area they decreased, but there was an increase in recruitment, mortality, turnover rates and basal area, as well as basal increment. The diameter increment on surviving individuals was higher in cyclone‐affected sites than in non‐affected sites. Bamboo cover did not affect richness or demographic rates (except mortality between T0 and T1). Natural impacts of this nature can lead to significant alterations of demographic rates, allowing the input of new species and influencing the pace of demographic processes.     

免疫系统：严重急性呼吸综合征冠状病毒2型感染后的一把双刃剑

免疫系统是人体内的一把双刃剑,它一方面能清除侵染的各类病原体,但另一方面其异常调控又能在人体中引发各类免疫性疾病,甚至导致死亡。本文将简要讨论人体免疫系统与新的冠状病毒﹝即严重急性呼吸综合征冠状病毒2型(severe acute respiratory syndrome coronavirus 2,SARS-CoV-2)〕感染的相互关系。一方面免疫系统能全方位地预防病毒感染,进化出一整套从分子到细胞、从短期到长期的病毒清除机制;另一方面,免疫系统又可能引发“细胞因子风暴”,给SARS-CoV-2的感染患者带来负面作用。本文还将讨论受到广泛关注的免疫相关的治疗策略,着重探讨抗体依赖的增强效应(antibody-dependent enhancement, ADE)可能给疫苗研发带来的困难与挑战。     

An Impaired Inflammatory and Innate Immune Response in COVID-19

The recent appearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people around the world and caused a global pandemic of coronavirus disease 2019 (COVID-19). It has been suggested that uncontrolled, exaggerated inflammation contributes to the adverse outcomes of COVID-19. In this review, we summarize our current understanding of the innate immune response elicited by SARS-CoV-2 infection and the hyperinflammation that contributes to disease severity and death. We also discuss the immunological determinants behind COVID-19 severity and propose a rationale for the underlying mechanisms.     

Storm impacts on alpine lakes: Antecedent weather conditions matter more than the event intensity

Extreme weather events may be just as important as gradual trends for the long‐term trajectories of ecosystems. For alpine lakes, which are exposed to both exacerbated atmospheric warming and intense episodic weather events, future conditions might not be appropriately forecast by only climate change trends, i.e. warming, if extreme events have the potential to deflect their thermal and metabolic states from their seasonal ranges. We used high‐frequency monitoring data over three open‐water seasons with a one‐dimensional hydrodynamic model of the high‐altitude Lake Muzelle (France) to show that rainstorms or windstorms, notwithstanding their intensity, did not trigger long‐lasting consequences to the lake characteristics when light penetration into the lake was not modified. In contrast, storms associated with high turbidity input from the watershed (“turbid storms”) strongly modified the lacustrine hydrodynamics and metabolism for the rest of the open‐water season through reduced light penetration. The long‐lasting effects of turbid storms were related to the inputs and in‐lake persistence of very light glacial suspensoids from the watershed. The occurrence of the observed turbid storms was not related to the wind or rain intensities during the events. Instead, the turbid storms occurred after dry and atypically warm spells, i.e. meteorological conditions expected to be more frequent in this alpine region in the upcoming decades. Consequently, storm events, notwithstanding their intensity, are expected to strongly imprint the future ecological status of alpine lakes under climate warming.     

Venom effects on monoaminergic systems

The monoamines, dopamine, epinephrine, histamine, norepinephrine, octopamine, serotonin and tyramine serve many functions in animals. Many different venoms have evolved to manipulate monoaminergic systems via a variety of cellular mechanisms, for both offensive and defensive purposes. One common function of monoamines present in venoms is to produce pain. Some monoamines in venoms cause immobilizing hyperexcitation which precedes venom-induced paralysis or hypokinesia. A common function of venom components that affect monoaminergic systems is to facilitate distribution of other venom components by causing vasodilation at the site of injection or by increasing heart rate. Venoms of some scorpions, spiders, fish and jellyfish contain adrenergic agonists or cause massive release of catecholamines with serious effects on the cardiovascular system, including increased heart rate. Other venom components act as agonists, antagonists or modulators at monoaminergic receptors, or affect release, reuptake or synthesis of monoamines. Most arthropod venoms have insect targets, yet, little attention has been paid to possible effects of these venoms on monoaminergic systems in insects. Further research into this area may reveal novel effects of venom components on monoaminergic systems at the cellular, systems and behavioral levels.