Usefulness of galactomannan detection in the diagnosis and follow-up of hematological patients with invasive aspergillosis

The usefulness of galactomannan detection using the Platelia Aspergillus test for the diagnosis of invasive aspergillosis was studied in 849 sera from 54 hematological patients with prolonged neutropenia, which were classified according to the risk for invasive aspergillosis. Three patients developed a proven invasive aspergillosis, one a probable invasive aspergillosis and 17 patients a possible invasive aspergillosis. Thirty-three patients showed no evidence of invasive aspergillosis. All patients with proven invasive aspergillosis had a high risk for invasive aspergillosis, while the one having probable invasive aspergillosis had intermediate risk. Detection of galactomannan in this study showed a sensitivity of 66.7% for patients with proven invasive aspergillosis and 50% for patients with proven and probable invasive aspergillosis. The specificity was 98% or higher in all groups studied. The predictive positive and negative values for patients with proven invasive aspergillosis were 66.7% and 98%, respectively. A rise in the concentration of galactomannan was observed in patients who failed to respond to the antifungal treatment. Galactomannan antigenemia preceded post-mortem histological diagnosis of invasive aspergillosis in two patients by 17 and 81 days, respectively. In conclusion, detection of galactomannan by the Platelia Aspergillus test allows for a specific and relatively sensitive diagnosis of invasive aspergillosis in hematological patients with a high and intermediate risk for invasive aspergillosis.     

入侵植物替代控制中土著种选择机制的研究

生物入侵对入侵地生态系统的稳定性及社会经济造成严重危害,成为全球三大环境问题之一。为有效治理入侵植物,结合常采用的物理、化学和生物防治等方法,从防治机制方面分析土著种替代控制入侵植物的有效性。通常土著种替代控制入侵植物是由于土著植物向环境中分泌化感物质,使得土壤中的微生物、动物以及化学成分相互作用,从而改变了入侵植物的生存环境。同时,土著植物利用自身的优势条件与入侵植物进行养分和光能等资源竞争,使入侵植物处于不利地位。通过对替代控制机理的概述,提出了替代植物的选择方法,讨论了需要进一步加强的领域,以期拓展替代控制这一领域的广度和深度,为入侵植物的生态防治提供理论依据。     

土壤微生物对不同种源乌桕生长的影响

【背景】土壤微生物对植物成功入侵具有重要影响,研究中国本地土壤微生物对美国入侵种乌桕的净生长效应有利于进一步理解乌桕成功入侵的机理。【方法】以本地和入侵2个种源多个种群的乌桕为试验材料,通过对土壤进行灭菌处理,研究土壤微生物对不同种源乌桕幼苗生长的影响。【结果】土壤微生物对入侵种乌桕具有正效应,与本地种相比,入侵种乌桕幼苗总生物量、相对生长速度、根冠比以及总叶面积、叶面积比、比叶面积等生物学指标在新鲜土壤中均表现出明显优势。种源和土壤处理间存在交互效应的指标显示土壤微生物去除对入侵种乌桕的抑制作用更为明显。这一结果与土壤自然天敌逃逸假说相背,入侵种乌桕在一定程度上具有较本地种更强的土壤微生物利用能力,在非根际土壤微生物的作用下入侵种乌桕具有较强的生长能力和明显的竞争优势。【结论与意义】本研究证实土壤微生物可能对乌桕成功入侵具有不可忽略的作用。由于该试验在乌桕起源地进行,结合在乌桕入侵地进行的研究有助于进一步分析土壤微生物对入侵的贡献作用;研究土壤微生物与入侵植物的互作关系有助于对入侵物种进行准确预测和有效控制,减少生物入侵对生态系统功能的破坏。     

Incompetence of neutrophils to invasive group A streptococcus is attributed to induction of plural virulence factors by dysfunction of a regulator

Group A streptococcus (GAS) causes variety of diseases ranging from common pharyngitis to life-threatening severe invasive diseases, including necrotizing fasciitis and streptococcal toxic shock-like syndrome. The characteristic of invasive GAS infections has been thought to attribute to genetic changes in bacteria, however, no clear evidence has shown due to lack of an intriguingly study using serotype-matched isolates from clinical severe invasive GAS infections. In addition, rare outbreaks of invasive infections and their distinctive pathology in which infectious foci without neutrophil infiltration hypothesized us invasive GAS could evade host defense, especially neutrophil functions. Herein we report that a panel of serotype-matched GAS, which were clinically isolated from severe invasive but not from non-invaive infections, could abrogate functions of human polymorphnuclear neutrophils (PMN) in at least two independent ways; due to inducing necrosis to PMN by enhanced production of a pore-forming toxin streptolysin O (SLO) and due to impairment of PMN migration via digesting interleukin-8, a PMN attracting chemokine, by increased production of a serine protease ScpC. Expression of genes was upregulated by a loss of repressive function with the mutation of csrS gene in the all emm49 severe invasive GAS isolates. The csrS mutants from clinical severe invasive GAS isolates exhibited high mortality and disseminated infection with paucity of neutrophils, a characteristic pathology seen in human invasive GAS infection, in a mouse model. However, GAS which lack either SLO or ScpC exhibit much less mortality than the csrS-mutated parent invasive GAS isolate to the infected mice. These results suggest that the abilities of GAS to abrogate PMN functions can determine the onset and severity of invasive GAS infection.     

入侵植物筛选方法在我国口岸防控中的应用建议

入侵植物是生物入侵中数量最多的类群,给全世界造成了重大的经济和环境影响。植物入侵的预测研究是口岸防控工作中的重要技术环节之一。本文介绍了入侵植物筛选方法的概念,简述了与之相关的基础理论、研究情况以及3种植物入侵的预测方法。综合来看,入侵植物筛选方法主要采用植物自身的生物生态学特性作为评估指标来筛选外来植物,能快速可靠地将外来植物评判为严重入侵植物、非入侵植物以及介于二者之间的一般入侵植物,因此该方法能为我国口岸防范外来植物入侵的管理提供基础技术支撑。当前我国入侵植物筛选方法的研究和应用尚处起步阶段,通过本文的简述期望引起相关人员对此问题进行探讨,并为我国口岸入侵植物防控工作提供理论参考。     

基于地理环境相似度的长江经济带入侵物种虚拟负样本生成方法

入侵物种空间分布建模的核心数据源来源于物种多样性采样(物种出现点和未出现点),然而,大多数入侵物种标本库只记录物种出现点样本信息,缺乏对未出现点(负样本)位置的记录。因此,生成有效的入侵物种虚拟负样本是建立物种空间分布模型的关键。本文提出了一种基于地理环境相似度的虚拟负样本生成方法。首先利用主成分分析(PCA)方法对地理环境原始变量进行线性相关性建模,基于提取的主成分,采用K-means算法对入侵物种样本进行聚类分析并计算各样本的地理环境相似度。在此基础上,通过建立基于主成分的入侵物种相似性度量与可信度计算框架来识别虚拟负样本。以长江经济带入侵物种一年蓬(Erigeron annuus)数据集为例,分析了整个区域虚拟负样本的可信度。结果表明,与空间随机采样和单类支持向量机采样相比,用本研究提出的方法生成的样本数据建立的logistic回归和支持向量机预测结果更优,验证了该方法的可行性与有效性。基于地理环境相似度的虚拟负样本抽样策略有助于解决由于随机采样而引起的误采样到潜在入侵点的难题,同时负样本的可信度能有助于识别不同等级的入侵物种适应区。     

Microsatellite variation points to local landscape plantings as sources of invasive pampas grass (Cortaderia selloana) in California

International trade in horticultural plants is a major pathway of introduction of invasive species. Pampas grass (Cortaderia selloana) is an invasive species of horticultural origin that is native to South America but cultivated as an ornamental in regions with Mediterranean climates worldwide. To gain insight into the introduction history of invasive populations in California, we analysed microsatellite marker variation in cultivated and invasive C. selloana. We sampled 275 cultivated plants from diverse sources and 698 invasive plants from 33 populations in four geographical regions of California. A model-based Bayesian clustering analysis identified seven distinct gene pools in cultivated C. selloana. Probabilities of assignment of invasive individuals to cultivated gene pools indicated that two gene pools accounted for the genomic origin of 78% of the invasive C. selloana sampled. Extensive admixture between cultivated source gene pools was detected within invasive individuals. Sources of admixed invasive individuals are probably landscape plantings. Consistent with the Bayesian assignment results indicating that multiple cultivated gene pools and landscape plantings are probable sources of invasive populations, F(ST) and neighbour-joining clustering analyses indicated multiple escapes from shared sources in each geographical region. No isolation by distance or geographical trend in reduction of genetic diversity was evident. Furthermore, a generally random and discontinuous distribution of proportional assignments of invasive populations to cultivated gene pools suggests that introductions occurred recurrently within each geographical region. Our results strongly suggest that dispersal through local landscape plantings has contributed to the range expansion of invasive C. selloana in California.     

Clonal relationship among invasive and non-invasive strains of enteroinvasive Escherichia coli serogroups

The genetic relatedness among 96 invasive Escherichia coli belonging to several serogroups and 13 non-invasive of several serotypes that share the same O antigen was investigated by multilocus enzyme electrophoresis analysis. The invasive strains were isolated in different parts of the world and most of them recovered from dysentery. Twenty-nine electrophoretic types were distinguished and the most invasive strains were found to belong to two major lineages. These results suggested that the invasive ability in these strains has evolved in divergent chromosomal backgrounds, presumably through the horizontal spread of plasmid-borne invasion genes. The maintenance of invasive phenotypes in separate lineages suggests that this ability confers a selective advantage to invasive strains.     

海口市外来入侵植物现状及防控对策

基于野外调查及文献资料及标本信息查阅,基本查清海口市外来入侵植物的种类组成、原产地、生活型、入侵途径,并对外来入侵植物在海口市的入侵危害进行等级划分。结果表明,海口市目前发现外来入侵植物115种,隶属于32科83属,其中菊科种数最多,有23种,占海口外来入侵植物总种数的20.0%;有92种原产地为美洲,占80.0%;有84种为草本植物,占73.0%;有111种为人类有意或无意引入,占96.5%;入侵植物中严重危害类(1级)有12种,一般危害类(2级)有24种,潜在危害类(3级)有25种,一般外来类(4级)有22种,32种还有待观察(5级)。文中提出对海口外来植物入侵的防控及管理对策。     

福建省主要入侵植物空间分异及其影响因素

在实地调查数据的基础上,本研究结合GIS空间分析技术和地理探测器模型,分析福建省入侵植物空间分布情况,以及地理与社会环境因子及其交互作用对入侵植物分布的影响.结果表明:福建省共记录入侵植物82种,其中,优势科为菊科,小蓬草、藿香蓟和空心莲子草出现频次最高.沿海区域的入侵植物物种数量多于内陆区域,福州和厦门为福建省外来入侵植物的两大热点地区.入侵植物在不同海拔均有分布,但入侵植物的种类随着海拔的升高总体呈下降趋势.地理探测器分析显示,自然环境因子中降水和社会经济因子中路网密度、人口密度是入侵植物空间分布的主要影响因子.各因子的空间交互作用会正向影响入侵植物的空间分布,这反映出入侵植物空间分布影响要素的复杂性.综上,将地理探测器应用到入侵植物研究领域是可行的,筛选出的环境指示因子可用于监测福建省入侵植物的适生区,从而为采取有效的防控措施提供科学依据.     

HMGB1 siRNA 对HT-29 细胞侵袭转移能力的影响

目的:观察干扰HMGB1表达对HT-29细胞侵袭转移能力的影响。方法:HMGB1 siRNA通过脂质体转染HT-29细胞,western blot和实时定量RT-PCR检测HT-29细胞中HMGB1蛋白和mRNA的表达,Transwell小室观察HT-29的转移侵袭能力。结果:干扰HMGB1后HMGB1蛋白和mRNA的表达均减少,HT-29的转移侵袭能力下降。结论:HMGB1能促进HT-29的转移侵袭能力,干扰其表达可抑制HT-29的转移侵袭。     

福建省农田生态系统外来入侵植物种类及其分布

为掌握福建省农田生态系统的外来入侵植物种类和分布情况,采用实地调查的方式,对福建省9市农田生态系统中的入侵植物进行调查,并分析了其种类组成、原产地、生活型、分布格局和分布类型及其入侵性等。结果表明,福建省农田生态系统有外来入侵植物30科65属共79种;其中以菊科（Asteraceae）物种数最多,为22种,占总种数的27.85%,其次是苋科（Amaranthaceae）有7种,豆科（Leguminosae）、禾本科（Gramineae）、旋花科（Convolvulaceae）和大戟科（Euphorbiaceae）各有5种。生活型以草本植物为主,占总种数的86.08%;原产于美洲的种类最多,占总种数的70.24%;入侵等级为恶性入侵（1级）的物种有10科22种,严重入侵（2级）有13科22种,局部入侵（3级）、一般入侵（4级）和有待观察类（5级）分别有9、18和8种;恶性入侵和严重入侵的植物种类占入侵植物总数的55.70%。从分布格局和分布类型来看,以福州市的农田生态系统入侵植物种类最多,为52种;不同农田类型中,以旱地中的入侵植物种数最多,有74种;按分布区域划分的全域分布种共13种,按农田类型划分的全域分布种有11种。因此,福建省农田生态系统入侵植物种类繁多,分布广泛,原产地多元化,且恶性和严重入侵植物占比较高,入侵形势严峻,应加强入侵植物的动态监控与防范,以保护生物多样性和生态安全。     

Influence of Drought and Shade on Seedling Growth of Native and Invasive Trees in the Seychelles

We studied the growth of seedlings of native and invasive tree species from secondary tropical forests on Mahé (Seychelles). We were interested in whether native or invasive species are more drought-tolerant, and therefore conducted a garden (pot) experiment comparing the growth of seedlings of five native and five invasive tree species under different light (7% and 60% transmittance) and water (natural and repeated drought stress) conditions. Differences in the responses of native and invasive species to these treatments were small. In both groups, mean relative growth rates were reduced only slightly by intermittent drought that caused wilting of leaves. However, invasive species produced clearly thinner leaves (high specific leaf area, SLA) and more root biomass than native species under high light, while these differences were small under low light. Native species performed better than invasive species under low light with low water availability. It appears that high phenotypic plasticity allows some fast-growing invasive species to cope with water stress by adjusting the relative allocation of resources to aboveground and belowground structures under high light, while this strategy is not effective when both light and water resources are limiting. We conclude that water stress may reduce the invasibility of shaded habitats by fast-growing invasive species, while water stress in unshaded habitats may have less effect on invasive species than previously recognized.     

干扰、地形和土壤对温州入侵植物分布的影响

分析自然因子和人为活动对入侵植物分布的影响,有助于预测外来植物的入侵.本研究采用路线踏查和样地调查相结合的方法,对温州地区外来入侵植物的组成和分布进行3次调查,同时记录样地土壤类型、地形、人为干扰等环境因子.使用典范对应分析(canonical correspondence analysis)进行排序,分析外来植物的分...     

入侵植物与本地植物互作对丛枝菌根真菌AMF侵染率的影响

外来植物成功入侵与菌根共生体存在着密不可分的关系,丛枝菌根真菌（AMF）侵染率是反映其侵染植物情况的重要指标,影响侵染率的因素很多,但是入侵植物与本地植物互作对AMF侵染率的影响目前还不清楚。因此,本研究以外来入侵植物黄顶菊Flaveria bidentis、豚草Ambrosia artemisiifolia、三叶鬼针草Bidens pilosa和本地植物狗尾草Setaria viridis、黄香草木犀Melilotus officinalis、藜Chenopodium album为研究对象,设置入侵植物单种处理、本地植物单种处理、每种入侵植物分别与本地植物两两混种处理以及每种入侵植物同时与所有本地植物混种处理,观察测定不同处理下入侵植物与本地植物根系丛枝、泡囊、菌丝及总侵染率,比较研究本地植物种类变化对入侵植物和本地植物根系AMF侵染率的影响,以及3种入侵菊科植物对本地植物AMF侵染率的影响规律是否一致。结果表明,与入侵植物单种相比,除豚草与藜、豚草同时与3种本地植物混种两个处理中,豚草根系的AMF菌丝及总侵染率显著增加外,其余所有处理中入侵植物总侵染率均无显著差异;与狗尾草或黄香草木犀单种相比,每种入侵植物同时与所有本地植物混种处理中,本地植物狗尾草和黄香草木犀根系上的AMF菌丝及总侵染率均显著降低,即随本地植物种类数目的增加,对本地植物根系的菌丝及总侵染率存在显著抑制作用,而对入侵植物无显著影响。     

中国外来入侵植物研究现状及存在的问题

生物入侵是当今各国发展的一大挑战,特别是像中国这样的发展中国家。然而,我们对外来入侵种的本底资料还很不清楚,更缺乏相关的深入调查;对生物入侵所造成的生态和经济影响还没有引起足够的重视,同时也忽视了盲目引种可能带来的各种危害。本文在文献调研的基础上,从外来植物的入侵历史和文化、中国外来入侵植物的调查现状、外来植物入侵对生态安全及经济的影响等方面进行了全面系统的总结,并提出了中国外来入侵植物研究领域存在的问题及应对措施。     

Effects of invasive seaweeds on feeding preference and performance of a keystone Mediterranean herbivore

The consequences of invasive species on ecosystem processes and ecological interactions remain poorly understood. Predator–prey interactions are fundamental in shaping species evolution and community structure and can be strongly modified by species introductions. To fully understand the ecological effects of invasive species on trophic linkages it is important to characterize novel interactions between native predators and exotic prey and to identify the impacts of invasive species on the performance of native predators. Although seaweed invasions are a growing global concern, our understanding of invasive algae—herbivore interactions is still very limited. We used a series of feeding experiments between a native herbivore and four invasive algae in the Mediterranean Sea to examine the potential of native sea urchins to consume invasive seaweeds and the impacts of invasive seaweed on herbivore performance. We found that three of the four invasive species examined are avoided by native herbivores, and that feeding behaviour in sea urchins is not driven by plant nutritional quality. On the other hand, Caulerpa racemosa is readily consumed by sea urchins, but may escape enemy control by reducing their performance. Recognizing the negative impacts of C. racemosa on herbivore performance has highlighted an enemy escape mechanism that contributes to explaining how this widespread invasive alga, which is preferred and consumed by herbivores, is not eradicated by grazing in the field. Furthermore, given the ecological and economic importance of sea urchins, negative impacts of invasive seaweeds on their performance could have dramatic effects on ecosystem function and services, and should be accounted for in sea urchin population management strategies.     

Non-lethal effects of an invasive species in the marine environment: the importance of early life-history stages

Studies examining the effects of invasive species have focussed traditionally on the direct/lethal effects of the invasive on the native community but there is a growing recognition that invasive species may also have non-lethal effects. In terrestrial systems, non-lethal effects of invasive species can disrupt early life-history phases (such as fertilisation, dispersal and subsequent establishment) of native species, but in the marine environment most studies focus on adult rather than early life-history stages. Here, we examine the potential for an introduced sessile marine invertebrate (Styela plicata) to exert both lethal and non-lethal effects on a native species (Microcosmus squamiger) across multiple early life-history stages. We determined whether sperm from the invasive species interfered with the fertilisation of eggs from the native species and found no effect. However, we did find strong effects of the invasive species on the post-fertilisation performance of the native species. The invasive species inhibited the settlement of native larvae and, in the field, the presence of the invasive species was associated with a ten-fold increase in the post-settlement mortality of the native species, as well as an initial reduction of growth in the native. Our results suggest that larvae of the native species avoid settling near the invasive species due to reduced post-settlement survival in its presence. Overall, we found that invasive species can have complex and pervasive effects (both lethal and non-lethal) across the early life-history stages of the native species, which are likely to result in its displacement and to facilitate further invasion.     

Commonly invasive serotypes of Streptococcus pneumoniae trigger a reduced innate immune response compared with serotypes rarely responsible for invasive infection

Although there are more than 90 serotypes of Streptococcus pneumoniae (or pneumococcus), it is not understood why a small number of serotypes account for most invasive infections. To investigate the human innate immune response triggered by different pneumococcal serotypes, monocyte-derived macrophages were exposed to a group of commonly and rarely invasive pneumococcal clinical isolates and tumor necrosis factor (TNF)-alpha production was measured. Commonly invasive pneumococcal serotypes triggered significantly less TNF-alpha production than serotypes rarely responsible for invasive infection (P<0.004). These data indicate that one factor influencing the invasive potential of a pneumococcal serotype is the magnitude of innate immune-mediated TNF-alpha production triggered by exposure to the organism and suggest that the integrated host response generated against commonly invasive pneumococcal serotypes may be less effective than the response directed against rarely invasive serotypes.     

外来植物成功入侵的生物学特征

外来植物的入侵能力与其性状之间的关系是入侵生态学中的基本问题之一.成功的入侵种常常能占据多样化的生境,具有较强的适应性、繁殖力和散布力.表型可塑性和遗传分化是外来入侵植物对生境异质性的两种适应策略;散布体多态型和散布途径多种化,使外来入侵植物迅速占领入侵生境,并进行远距离扩散;无性生殖和有性生殖并存,并根据生境和入侵阶段权衡的繁育对策不仅使入侵种群大面积暴发成为可能,而且直接影响散布机制并对种群遗传结构具有调节作用.高效的资源利用性竞争,加之以化感作用为基础的干扰性竞争使植物更具入侵性.