Babesia Bovis Ligand-Receptor Interaction: AMA-1 Contains Small Regions Governing Bovine Erythrocyte Binding

Apical membrane antigen 1 is a microneme protein which plays an indispensable role during Apicomplexa parasite invasion. The detailed mechanism of AMA-1 molecular interaction with its receptor on bovine erythrocytes has not been completely defined in Babesia bovis. This study was focused on identifying the minimum B. bovis AMA-1-derived regions governing specific and high-affinity binding to its target cells. Different approaches were used for detecting ama-1 locus genetic variability and natural selection signatures. The binding properties of twelve highly conserved 20-residue-long peptides were evaluated using a sensitive and specific binding assay based on radio-iodination. B. bovis AMA-1 ectodomain structure was modelled and refined using molecular modelling software. NetMHCIIpan software was used for calculating B- and T-cell epitopes. The B. bovis ama-1 gene had regions under functional constraint, having the highest negative selective pressure intensity in the Domain I encoding region. Interestingly, B. bovis AMA-1-DI (¹⁰⁰YMQKFDIPRNHGSGIYVDLG¹¹⁹ and ¹²⁰GYESVGSKSYRMPVGKCPVV¹³⁹) and DII (³⁰²CPMHPVRDAIFGKWSGGSCV³²¹)-derived peptides had high specificity interaction with erythrocytes and bound to a chymotrypsin and neuraminidase-treatment sensitive receptor. DI-derived peptides appear to be exposed on the protein’s surface and contain predicted B- and T-cell epitopes. These findings provide data (for the first-time) concerning B. bovis AMA-1 functional subunits which are important for establishing receptor-ligand interactions which could be used in synthetic vaccine development.     

Surface and Groundwater Quality Evolution in the Agrio and Guadiamar Rivers After the Aznalcóllar Mine Spill (SW Spain): Lessons Learned

Mine Water and the Environment - The failure of the tailing dam at the Aznalcóllar mine (SW Spain) in 1998 released ≈ 6 million m3 of pyrite sludge and acidic...     

Neuro-semantic prediction of user decisions to contribute content to online social networks

Neural Computing and Applications - Understanding at microscopic level the generation of contents in an online social network (OSN) is highly desirable for an improved management of the OSN and the...     

Guest editorial to the theme section on multi-level modeling

Software and Systems Modeling -     

Removal of natural organic matter and THM formation potential by ultra- and nanofiltration of surface water

Natural organic matter (NOM) and trihalomethane formation potential (THMFP) removal were evaluated by ultrafiltration (UF) and nanofiltration (NF). Ten different raw water sources in Alicante province (SE Spain) were analysed. Five types of membranes of different materials were tested with a dead-end-type stirred UF cell. Additional measurements, such as dissolved organic carbon, ultraviolet absorbance (254nm), THMFP, ion concentration, pH, conductivity, etc. were made on raw water, permeates and concentrates. The SUVA value was used to determine the hydrophobicity of the water analysed. The elimination of NOM and THMFP is correlated with the molecular weight (MW) of NOM determined by size exclusion chromatography (SEC). The flux decline trends were correlated with cation concentration. NOM removal by UF is low, which correlates with the average MW determined by SEC with an average value of 922g/mol (between 833 and 1031g/mol). However, the NOM removal obtained with the NF90 and NF270 NF membranes for all water sources is almost complete (90%). THMFP removal is related to hydrophobicity and permeability of membrane. The NFT50 membrane removes almost 100% of the THMFP of more hydrophobic waters.     

发达资本主义的集体消费与城市矛盾

不同社会群体在生产体系中所处的地位决定了产品在他们之间的分配．这就使得社会不平等成为所有阶级社会最显著的特征；一旦我们否认了社会层级体系（the system of socialstratification．涉及生产的经济和象征性的分配）与社会阶级体系（the system of socialclasses，基于生产体系以及各阶级之间的权力关系）之间的固有联系．并且认为前者依赖于后者，那么就有必要从生产方式的阶段和社会体系的历史形成过程出发，阐明这种社会不平等的具体形态。因而，以主流阶级总是有好结局的宿命论为基础的“富人”与”穷人”永不平等的历史．便让位于消费层面上关于社会生产分化的精确分析和对于一定类型的社会关系基本逻辑的研究．而这种社会关系的体验形式则是沉重的日常生活。     

都市理论和中国的城市化

这期《国外城市规划》的文集中收录的文章．展现了我对于都市理论探索的一个总体面貌，时间跨越了30年．从1972年首次发表的法语版《城市问题》到1996至2004年间关于流动空间和地方空间的理论著作。很显然．它们并不是一成不变的．理论在数十年间发生了变化。实际上．在早期理论中的一些基本要素与后期概念的发展是相互抵触的。或许这正是它应该呈现的样子．因为从根本上来说我是一名研究者，而不是哲学家，对我来说，理论的建构是用来理解、修正社会和空间过程的工具。在研究实践中．我对这些概念去伪存精．并发展了一些新的概念和新的理论解释来说明我所观察到的现象。     

Cryptosporidium spp. and Giardia duodenalis in two areas of Galicia (NW Spain)

The aim of the present study was to investigate the environmental dispersal of Cryptosporidium spp. and Giardia duodenalis in two distinct areas (coastal and inland) in Galicia (NW Spain). Faecal samples were collected from healthy asymptomatic domestic (cows and sheep) and wild animals (deer and wild boars) in the selected areas. In each of the selected areas, samples of untreated water (influent) and of treated water (final effluent) were collected from each of the 12 drinking water treatments plants (DWTPs) and 12 wastewater treatment plants (WTPs) under study. Analysis of a single sample from each of the 635 (coastal) and 851 (inland) domestic and wild animals selected at random revealed that the prevalences of cryptosporidiosis and giardiosis in coastal area were 9.2% and 15.9% respectively, and in inland area, 13.7% and 26.7% respectively. In the coastal area, Cryptosporidium spp. oocysts were detected in influent and effluent samples from 2/12 (16.6%) DWTPs and 8/12 (66.6%) WTPs, while G. duodenalis cysts were detected in influent and effluent samples from 3/12 (25.0%) DWTPs and 12/12 (100%) WTPs. The concentrations were notably higher in WTPs; the mean parasite concentrations in the final treated effluent were 10 oocysts per litre and 137.8 cysts per litre for Cryptosporidium and Giardia, respectively. The mean concentration of G. duodenalis cysts per litre was significantly higher (P < 0.05) than the mean concentration of Cryptosporidium spp. oocysts per litre in both the influent and the effluent samples from all the treatment plants. In the coastal area, C. parvum, C. hominis and G. duodenalis assemblages A (I and II) and E were most repeatedly detected. In the inland area, C. parvum, C. andersoni and G. duodenalis assemblages A (I and II), B and E were most frequently identified.     

Effects of indoor drinking water handling on trihalomethanes and haloacetic acids

In this study, different tap water handling strategies were investigated to evaluate the effects on two principal chlorinated DBPs, trihalomethanes (THMs) and haloacetic acids (HAAs). Tap water samples collected in the Quebec City (Canada) distribution system on a spatio-temporal basis were subjected to diverse indoor handling scenarios: storing water in the refrigerator, boiling water followed by storage and, finally, filtering water with a point-of-use commercial pitcher also followed by storage. In the first two cases, the use of covered and uncovered pitchers was investigated separately, while in the last case, both the use of new and used filters was compared. In all cases, maximum storage time was 48h. Results demonstrated that in some cases, water handling scenarios have considerable effect, and in other cases, little or no effect. Removal of THM concentrations by simple storage was high (on average 30%) and very high by boiling and filtering with subsequent storage in the refrigerator (on average, 87% and 92%, respectively). In scenarios where water was stored in uncovered pitchers (with or without previous boiling and filtering), the THM decrease was higher for increased storage times. However, storage did not have any effect on HAAs, whereas boiling decreased levels of trichloroacetic acid (TCAA) (on average 42%) and increased levels of dichloroacetic acid (DCAA) (on average 35%), resulting in unchanged average levels of total HAAs. The use of the filtration pitcher decreased HAA levels dramatically (on average 66%). Percentages of change in chlorinated DBPs in the different scenarios varied according to initial concentrations in tap water (baseline water), that is, according to the spatio-temporal variations of these substances in the distribution system. On the basis of these results, the paper discusses implications regarding public health protection and exposure assessment for epidemiological studies.