One-year survey of opportunistic premise plumbing pathogens and free-living amoebae in the tap-water of one northern city of China

In this study, qPCR was used to quantify opportunistic premise plumbing pathogens(OPPPs) and free-living amoebae in 11 tap water samples collected over four seasons from a city in northern China. Results demonstrated that the average numbers of gene copies of Legionella spp. and Mycobacterium spp. were significantly higher than those of Aeromonas spp.(p < 0.05). Legionella spp. and Mycobacterium spp. were 100%(44/44) positively detected while P. aeruginosa and Aeromonas spp. were 79.54%(35/44) and 77.27%(34/44) positively detected. Legionella pneumophila was only detected in 4 samples(4/44), demonstrating its occasional occurrence. No Mycobacterium avium or Naegleria fowleri was detected in any of the samples. The average gene copy numbers of target OPPPs were the highest in summer,suggesting seasonal prevalence of OPPPs. Average gene copy numbers of OPPPs in the taps of low-use-frequency were higher than in taps of high-use-frequency, but the difference was not significant for some OPPPs(p > 0.05). Moderate negative correlations between the chlorine concentration and the gene copy numbers of OPPPs were observed by Spearman analysis(rsranged from -0.311 to -0.710, p < 0.05). However, no significant correlations existed between OPPPs and AOC, BDOC, or turbidity. Moderate positive correlations were observed between the target microorganisms, especially for Acanthamoeba spp., through Spearman analysis(p < 0.05). Based on our studies, it is proposed that disinfectant concentration, season, taps with different-use frequency, OPPP species, and potential microbial correlations should be considered for control of OPPPs in tap water.

Ecology of testate amoebae in Dajiuhu peatland of Shennongjia Mountains, China, in relation to hydrology

This study investigates the testate amoeba communities of a large peatland in Central China. The ecology and seasonal variability of testate amoeba communities were studied during 2009-2010. Investiga- tion of environmental controls using ordination showed that the relationship between testate amoeba communities and depth to water table （DWT） and pH are extremely weak. The small proportion of variance explained by water table depth here （only 1.9% in the full data） shows that the hydrological control is weaker than we expected in this peatland, and weaker than any study we are aware of using a similar methodology. Attempts to develop species- environment （transfer function） models or identify indi- cator species for future palaeoecological studies were unsuccessful. Previous large-scale studies of peatland testate amoeba ecology have been largely restricted to Europe and North America and results have been relatively consistent among studies. Our results contrast with this consensus and suggest that at least in minerotrophic peatlands in China testate amoeba communities may be primarily controlled by different environmental variables. In China, testate amoebae have been relatively little studied but may prove to be valuable for a variety of applications in palaeoecology and biomonitoring and much further work is required.

Testate amoebae communities from some freshwater and soil habitats in China （Hubei and Shandong Provinces）

Seventy-eight species and forms of testate amoebae were identified from 29 freshwater and soil habitats in three territories of China （Shandong and Hubei Provinces）. Most abundant species from the genera Plagiopyxis, Centropyxis and Trinema represent the globally-distributed and eurybiont group of testate amoe- bae. The species richness was observed to be the lowest （7-12 species per biotope） in sandy sediments of the Yangtze River, but considerably higher （20-30 taxa） in soil environment. In the range of terrestrial habitats, the most remote communities from Laoshan Mountain in Shandong Province, China manifested the highest difference from others. On the other hand, communities originated in the most distant from industrial center places （Guifeng Mountain in Hubei Province, China） possess the most peculiar species composition including specific Gondwa- nian taxa （e.g. Nebela bigibbosa）. In sum, the results obtained provide the evidence that the community complexity and specificity reduce in the places located within areas that are highly populated and intensively visited by humans.

Various brain-eating amoebae: the protozoa, the pathogenesis, and the disease

Among various genera of free-living amoebae prevalent in nature,some members are identified as causative agents of human encephalitis,in which Naegleria fowleri followed by Acanthamoeba spp.and Balamuthia mandrillaris have been successively discovered.As the three dominant genera responsible for infections,Acanthamoeba and Balamuthia work as opportunistic pathogens of granulomatous amoebic encephalitis in immunocompetent and immunocompromised individuals,whereas Naegleria induces primary amoebic meningoencephalitis mostly in healthy children and young adults as a more violent and deadly disease.Due to the lack of typical symptoms and laboratory findings,all these amoebic encephalitic diseases are difficult to diagnose.Considering that subsequent therapies are also affected,all these brain infections cause significant mortality worldwide,with more than 90%of the cases being fatal.Along with global warming and population explosion,expanding areas of human and amoebae activity in some regions lead to increased contact,resulting in more serious infections and drawing increased public attention.In this review,we summarize the present information of these pathogenic free-living amoebae,including their phylogeny,classification,biology,and ecology.The mechanisms of pathogenesis,immunology,pathophysiology,clinical manifestations,epidemiology,diagnosis,and therapies are also discussed.

Investigating the bacterial community and amoebae population in rural domestic wastewater reclamation for irrigation

Reclamation of domestic wastewater for agricultural irrigation is viewed as a sustainable option to create an alternative water source and address water scarcity. Free-living amoebae（FLA）, which are amphizoic protozoa, are widely distributed in various environmental sources. The FLA could cause considerable environmental and health risks. However, little information is available on the risk of these protozoa. In this study, we evaluated the feasibility using rural domestic wastewater for agricultural irrigation, and analyzed dynamic changes of the microbial community structure and FLA populations in raw and treated wastewater, as well as the phyllosphere and rhizosphere of lettuce production sites that were irrigated with different water sources. The bacterial community dynamics were analyzed by terminal restriction fragment length polymorphism（T-RFLP）. The bacterial community structures in the influent were similar to that in the effluent, while in some cases relative abundances varied significantly. The populations of Acanthamoeba spp. and Hartmannella vermiformis in the anaerobically treated wastewater were significantly higher than in the raw wastewater. The vegetables could harbor diverse amoebae, and the abundances of Acanthamoeba spp. and H. vermiformis in the rhizosphere were significantly higher than in the phyllosphere. Accordingly, our studies show insight into the distribution and dissemination of amoebae in wastewater treatment and irrigation practices.

Ecology of testate amoebae and their potential use as palaeohydrologic indicators from peatland in Sanjiang Plain, Northeast China

Testate amoebae are sensitive indicators of substrate moisture in peaflands. Over the last decades, they have been studied to reconstruct hydrological changes since the Holocene. However, these studies have been geographically restricted to North America and Europe. We conducted the first investigation of testate amoebae on the largest continental fresh water wetland in the Sanjiang Plain, China. The objectives of this study were to provide baseline data on the ecology of testate amoebae in the peatlands of Northeast China and to assess the potential of using them as environmental indicators in this ecosystem. We examined modem testate amoeba assemblages and species-environmental relationships at 46 microsites within 5 waterlogged depressions. The environmental parameters measured included： depth to water table, pH, and loss on ignition. The results showed that the dominant species were Trinema complanatum type, Euglypha rotunda type, Euglypha strigosa type, and Centropyxis cassis type. Redundancy analysis demonstrates that water table depth has the most important effect on testate amoeba assemblages, explaining 16.7% （p=0.002） of the total variance, pH was not a statistically significant factor for testate amoeba assemblages. Weighted averaging and weighted averaging partial least squares models were used to build transfer functions for depth to water table. The best performing transfer function was generated by the weighted averaging partial least squares model with an r^2LOSO of 0.62 and RMSEPLoso of 6.96 era. Results indicate that testate amoebae in waterlogged depression peatland have the potential to be used as indicators for hydrological changes and for palaeohydrologic reconstructions in the Sanjiang Plain.

应用rioja软件包建立有壳变形虫-环境因子转换函数

应用R语言rioja软件包的加权平均(Weighted Averaging,WA)和加权平均偏最小二乘(Weighted AveragingPartial Least Squares,WA-PLS)模型建立了长白山区泥炭藓泥炭地有壳变形虫与水位埋深(depth to water table,DWT)、pH和泥炭湿度的转换函数,为古环境定量重建奠定了基础,也提供了rioja软件包应用的实例和参考。结果表明水位埋深以WA-PLS模型最佳(预测均方根误差RMSEP为7.39 cm,R2=0.74);对于pH和泥炭湿度,WA-PLS第一分量和WA.inv都产生了最小的RMSEP和较高的R2值。pH的RMSEP为0.18,R2为0.72。泥炭湿度的RMSEP为1.95%,R2为0.62。如果泥炭剖面的有壳变形虫种类组成与本研究的训练样本集相同,水位埋深、pH和泥炭湿度可以分别以±7.39 cm、±0.18和±1.95%的平均误差进行重建。

Tissue cell differentiation and multicellular evolution via cytoskeletal stiffening in mechanically stressed microenvironments

Evolution of eukaryotes from simple cells to complex multicellular organisms remains a mystery. Our postulate is that cytoskeletal stiffening is a necessary condition for evolution of complex multicellular organisms from early simple eukaryotes. Recent findings show that embryonic stem cells are as soft as primitive eukaryotes-amoebae and that differentiated tissue cells can be two orders of magnitude stiffer than embryonic stem cells. Soft embryonic stem cells become stiff as they differentiate into tissue cells of the complex multicellular organisms to match their microenvironment stiffness. We perhaps see in differentiation of embryonic stem cells (derived from inner cell mass cells) the echo of those early evolutionary events. Early soft unicellular organisms might have evolved to stiffen their cytoskeleton to protect their structural integrity from external mechanical stresses while being able to maintain form, to change shape, and to move.

网络教学平台下分布式数据库技术的研究

在对当前分布式数据库技术,特别是分布式数据库管理系统进行分析的基础上,运用开源Amoeba for A ladd in项目对如何搭建分布式的网络教学资源平台进行全面阐述,探讨网络教学资源平台的整体和局部设计,进而提出一种在网络教学资源平台中实现分布式数据库的方法.最终设计并实现一套通用的分布式网络教学资源平台.结合分布式数据库技术来设计网络教学系统可实现教学资源更大范围的共享与整合.

基于Amoeba中间件的分布式数据库管理系统

在数据库运用普遍建立于计算机网络之上的环境下,通过Amoeba中间件,实现对服务器集群的统一管理。该系统利用Amoeba中间件,通过对服务器信息的收集和修改,实现Amoeba服务器参数、MySQL数据库服务器参数、负载均衡、读写分离规则以及数据切分功能的配置。该系统避免了繁琐而杂乱的各个服务器独立配置,让管理人员从整体上掌控整个服务器系统运行状态。最后,实验验证,该套系统能够有效管理和配置服务器运行参数。

Towards Physarum Robots: Computing and Manipulating on Water Surface

Plasmodium of Physarum polycephalum is an ideal biological substrate for implementing concurrent anu parauel computation, including combinatorial geometry and optimization on graphs. The scoping experiments on Physarum computing in conditions of minimal friction, on the water surface were performed. The laboratory and computer experimental results show that plasmodium of Physarum is capable of computing a basic spanning tree and manipulating of light-weight objects. We speculate that our results pave the pathways towards the design and implementation of amorphous biological robots.

Specific Lethal Effects of Trace Neutral Red on Amoeba discoides and Trichodina

[ Objective] The aim of this study was to provide the reference for the artificial breeding of aquatic animals. [ Method] Amoeba discoides and Trichodina were treated by neutral red solution with different concentrations to observe the physiological activities of organelles in their death processes. Effects of neutral red solution on the growth of common aquatic animals such as Paramecium caudatum, Euglena viridis and Brachionus plicatilis were analyzed, and the specific lethal mechanism of trace neutral red to A. discoides and Trichodina was also preliminarily studied. [ Re- suit] The neutral red solution at a concentration of 0.5 mg/L damaged the physiological function of contractile vacuole in Trichodina and also had the specific lethal effect on Tdchodina, but it had no effect on the growth and reproduction of non-parasitic protozoa and B. p/icatilis. Neutral red so- lution with certain concentration led to disorder of the physiological functions of A. discoides, such as assimilation and rejection, which was a main factor that caused the death of A. discoides. [ Conclusion] With the advantages such as targeting, safety and easiness to be oxidized and decom- posed, neutral red is an ideal drug for treating the diseases caused by A. discoides and Trichodina, and its suitable concentration is 0. 5 mg/L.

THE SCANNING NUCLEAR MICROPROBE AT SINR

This paper describes the scanning nuclear microprobe facilities established at the Shanghai Institute of Nuclear Research. The Russion quadruplet constructed with four magnetic quadrupolets is used for microbeam formation. The long focus of the lens makes the working distance long enough to accommodate the scanning coils and the detectors for PIXE, RBS, RFS, NRA and SE experiments. A 5 μm focussed beam is scanned continously by a pair of coils. A multiparameter multidetector data system for the nuclear microprobe is based on the idea of Total quantitative scanning analysis (TQSA) suggested by Melbourne University. A digital graphic displayer is a good substitute for an ordinary storage oscilloscope for on- line scanned area monitoring. The new microprobe meets high demands of biologists and geologists on applications.

微内核操作系统设计方法及其实例的比较

微内核操作系统提供了并行计算机所需的功能和性能，是并行操作系统的发展方向讨论微内核操作系统的基本设计方法，并介绍几个典型实例：Ａｍｏｅｂａ，Ｍａｃｈ，Ｃｈｏｒｕｓ．

大变形虫（Amoeba proteus）室内培养方法的比较

大变形虫（Amoeba proteus）是原生动物门肉足亚门（Sarcodina）、根足总纲（Rhizopoda）、叶足纲（Lobosea）、变形目（Amoebida）、变形虫科（Amoebidae）、变形虫属（Amoeba）的代表动物，最主要的特征是虫体的细胞质可以延伸形成伪足，做变形动物（amoeboid movement）．一般生活在池塘、水坑中，通常附着在浸没的植物上或粘性沉渣中，密度小，野外采集困难，镜检难度大．为满足高校无脊椎动物学实验教学的需要，本文比较了室内培养大变形虫的几种方法，以获得充足的实验材料．

Effect of Protein Dimerization on Ion Conductivity of Gramicidin A Channel Studied Using Polarizable Force Field

In studies of ion channel systems,due to the huge computational cost of polarizable force elds,classical force elds remain the most widely used for a long time.In this work,we used the AMOEBA polarizable atomic multipole force eld in enhanced sampling simula-tions of single-channel gramicidin A(gA)and double-channel gA systems and investigated its reliability in characterizing ion-transport properties of the gA ion channel under dimer-ization.The inuence of gA dimerization on the permeation of potassium and sodium ions through the channel was described in terms of conductance,di usion coeffcient,and free energy pro le.Results from the polarizable force eld simulations show that the conductance of potassium and sodium ions passing through the single-and double-channel agrees well with experimental values.Further data analysis reveals that the molecular mechanism of protein dimerization a ects the ion-transport properties of gA channels,i.e.,protein dimer-ization accelerates the permeation of potassium and sodium ions passing through the double-channel by adjusting the environment around gA protein(the distribution of phospholipid head groups,ions outside the channel,and bulk water),rather than directly adjusting the conformation of gA protein.

Audio Hijack Pro万能录音机

Audio Hijack Pro是由Rogue amoeba开发的音频软件，它的功能非常强大只要是你的Mac能放的声音。这个程序都可以录下来．从流媒体广播到DVD音频．还可以为任何程序作数字声效处理，可以使iTunes和Quicktime电台效果明显改善。

Relationships between testate amoeba communities and water quality in Lake Donghu, a large alkaline lake in Wuhan, China

The middle Yangtze Reach is one of the most developed regions of China. As a result, most lakes in this area have suffered from eutrophication and serious environmental pollution during recent decades. The aquatic biodiversity in the lakes of the area is thus currently under significant threat from continuous human activities. Testate amoebae （TA） are benthic （rarely planktonic） microorganisms characterized by an agglutinated or autogenous shell. Owing to their high abundance, preservation potential in lacustrine sediments, and distinct response to environmental stress, they are increasingly used as indicators for monitoring water quality and reconstructing palaeoenvironmental changes. However this approach has not yet been developed in China. This study presents an initial assessment of benthic TA assemblages in eight lakes of Lake Donghu in the region of Wuhan, China. Testate amoeba community structure was most strongly correlated to water pH. In more alkaline conditions, communities were dominated by Centropyxis aculeata, Difflugia oblonga, Pontigulasia compressa, Pon. elisa and Lesquereusia modesta. These results are consistent with previous studies and show that TA could be useful for reconstructing past water pH fluctuations in China. To achieve this, the next step will be to expand the database and build transfer function models.