Influence of water management on the active root-associated microbiota involved in arsenic, iron and sulfur cycles in rice paddies

In recent years, the role of microorganisms inhabiting rice rhizosphere in promoting arsenic contamination has emerged. However, little is known concerning the species and metabolic properties involved in this phenomenon. In this study, the influence of water management on the rhizosphere microbiota in relation to arsenic dissolution in soil solution was tested. Rice plants were cultivated in macrocosms under different water regimes: continuous flooding, continuous flooding with a 2 weeks-period drainage before flowering and dry soil watered every 10 days. The active bacterial communities in rhizosphere soil and in rhizoplane were characterized by 16S rRNA pyrosequencing. An in-depth analysis of microbial taxa with direct or indirect effects on arsenic speciation was performed and related contribution was evaluated. Continuous flooding promoted high diversity in the rhizosphere, with the plant strongly determining species richness and evenness. On the contrary, under watering the communities were uniform, with little differences between rhizosphere soil and rhizoplane. Arsenic-releasing and arsenite-methylating bacteria were selected by continuous flooding, where they represented 8 % of the total. On the contrary, bacteria decreasing arsenic solubility were more abundant under watering, with relative abundance of 10 %. These values reflected arsenic concentrations in soil solution, respectively 135 \ub5g L-1 and negligible in continuous flooding and under watering. When short-term drainage was applied before flowering, intermediate conditions were achieved. This evidence strongly indicates an active role of the rhizosphere microbiota in driving arsenic biogeochemistry in rice paddies, influenced by water management, explaining amounts and speciation of arsenic often found in rice grains

A study of microbial communities on terracotta separator and on biocathode of air breathing microbial fuel cells

Recently, terracotta has attracted interest as low-cost and biocompatible material to build separators in microbial fuel cells (MFCs). However, the influence of a non-conductive material like terracotta on electroactive microbiological communities remains substantially unexplored. This study aims at describing the microbial pools developed from two different seed inocula (bovine and swine sewage) in terracotta-based air-breathing MFC. A statistical approach on microbiological data confirmed different community enrichment in the MFCs, depending mainly on the inoculum. Terracotta separators impeded the growth of electroactive communities in contact with cathodes (biocathodes), while a thick biofilm was observed on the surface (anolyte-side) of the terracotta separator. Terracotta-free MFCs, set as control experiments, showed a well-developed biocathode, Biocathode-MFCs resulted in 4 to 6-fold higher power densities. All biofilms were analyzed by high-throughput Illumina sequencing applied to 16S rRNA gene. The results showed more abundant (3- to 5-fold) electroactive genera (mainly Geobacter, Pseudomonas, Desulfuromonas and Clostridia MBA03) in terracotta-free biocathodes. Nevertheless, terracotta separators induced only slight changes in anodic microbial communities

Bioelectrochemical Nitrogen fixation (e-BNF): Electro-stimulation of enriched biofilm communities drives autotrophic nitrogen and carbon fixation

A new approach to microbial electrosynthesis is proposed, aimed at producing whole biomass from N2 and inorganic carbon, by electrostimulation of complex microbial communities. On a carbon-based conductor under constant polarization ( 120.7\u202fV vs SHE), an electroactive biofilm was enriched with autotrophic nitrogen fixing microorganims and led to biomass synthesis at higher amounts (up to 18 fold), as compared to controls kept at open circuit (OC). After 110\u202fdays, the electron transfer had increased by 30-fold, as compared to abiotic conditions. Metagenomics evidenced Nif genes associated with autotrophs (both Archaea and Bacteria) only in polarized biofilms, but not in OC. With this first proof of concept experiment, we propose to call this promising field \u2018bioelectrochemical nitrogen fixation\u2019 (e-BNF): a possible way to \u2018power\u2019 biological nitrogen fixation, organic carbon storage and soil fertility against desertification, and possibly a new tool to study the development of early prokaryotic life in extreme environments

Characterization of As(III) oxidizing Achromobacter sp. strain N2 : effects on arsenic toxicity and translocation in rice

Achromobacter sp. strain N2 was isolated from a pyrite-cinder-contaminated soil and presented plant growth promoting traits (ACC deaminase activity, production of indole-3-acetic and jasmonic acids, siderophores secretion, and phosphate solubilization) and arsenic transformation abilities. Achromobacter sp. strain N2 was resistant to different metals and metalloids, including arsenate (100 mM) and arsenite (5 mM). The strain was resistant to ionic stressors (i.e., arsenate and NaCl), whereas bacterial growth was impaired by osmotic stress. Strain N2 was able to oxidize 1.0 mmol L-1 of arsenite to arsenate in 72 h. This evidence was supported by the retrieval of an arsenite oxidase AioA gene highly homologous to arsenite oxidases of Achromobacter and Alcaligenes species. Rice seeds of Oryza sativa (var. Loto) were bio-primed with ACCD-induced and non-induced cells in order to evaluate the effect of inoculation on rice seedlings growth and arsenic uptake. The bacterization with ACCD-induced cells significantly improved seed germination and seedling heights if compared with the seeds inoculated with non-induced cells and non-primed seeds. Enhanced arsenic uptake was evidenced in the presence of ACCD-induced cells, suggesting a role of ACCD activity on the mitigation of the toxicity of arsenic accumulated by the plant. This kind of responses should be taken into account when proposing PGP strains for improving plant growth in arsenic-rich soils

Parameter identification in pipeline networks: transient-based expectation-maximization approach for systems containing unknown boundary conditions

The simulation of hydraulic transients within fluid line networks is important for many applications (for example, water hammer analysis within distribution networks). However, in many instances, modeling efforts are impeded by the fact that the pipeline parameters are either unknown or can vary significantly from their assumed design values. Consequently, research efforts have focused on the development of parameter identification techniques, mapping from measured transient data to pipeline parameter estimates. A limitation of previous works has been the need for systems to have all boundary conditions either measured or known (e.g., transient pressure measurements or reservoir boundary conditions). This paper aims to relax this requirement and presents a parameter identification method for fluid line networks based on transient-state measurements of the hydraulic state variables of pressure and flow, in the presence of unmeasured and unknown boundary conditions. Utilizing a Laplace-domain admittance matrix representation of the system, the contribution to the hydraulic system dynamics from the measured and unmeasured state variables (i.e., boundary conditions) is made explicit. This model is then used as the basis for the development of a parameter estimation methodology based on the expectation-maximization (EM) algorithm. The importance of the EM approach is that it provides a framework for parameter estimation in the presence of unmeasured state variables by effectively integrating out the influence of the unmeasured variables. Numerical examples demonstrate the utility of this method for a network with a range of pipeline models

Bioprospecção de bactérias isoladas de milho para promoção de crescimento de plantas.

Isolados bacterianos associados a raízes de milho identificados por sequenciamento parcial do gene 16S RNAr foram avaliados em testes de promoção de crescimento vegetal. Também foram conduzidos testes in vitro para a capacidade de produção de sideróforos, solubilização de fosfato, produção de AIA, FBN e produção de enzimas líticas. Cinco isolados apresentaram resultados promissores na caracterização enzimática e nos testes de atividade promotora de crescimento e, portanto, poderão ser avaliados in vivo quanto a parâmetros de crescimento vegetal em ensaios em casa de vegetação

An integrated and coordinated approach to preventing recurrent coronary heart disease events in Australia: Policy statement from the Australian Cardiovascular Health and Rehabilitation Association

• Implementing existing knowledge about cardiac rehabilitation (CR) and heart failure management could markedly reduce mortality after acute coronary syndromes and revascularisation therapy. • Contemporary CR and secondary prevention programs are cost-effective, safe and beneficial for patients of all ages, leading to improved survival, fewer revascularisation procedures and reduced rehospitalisation. • Despite the proven benefits attributed to these secondary prevention interventions, they are not well attended by patients. • Modern programs must be flexible, culturally safe, multifaceted and integrated with the patient's primary health care provider to achieve optimal and sustainable benefits for most patients

Transient Modeling of Arbitrary Pipe Networks by a Laplace-Domain Admittance Matrix

©2009 ASCEAn alternative to the modeling of the transient behavior of pipeline systems in the time-domain is to model these systems in the frequency-domain using Laplace transform techniques. Despite the ability of current methods to deal with many different hydraulic element types, a limitation with almost all frequency-domain methods for pipeline networks is that they are only able to deal with systems of a certain class of configuration, namely, networks not containing second-order loops. This paper addresses this limitation by utilizing graph theoretic concepts to derive a Laplace-domain network admittance matrix relating the nodal variables of pressure and demand for a network comprised of pipes, junctions, and reservoirs. The adopted framework allows complete flexibility with regard to the topological structure of a network and, as such, it provides an extremely useful general basis for modeling the frequency-domain behavior of pipe networks. Numerical examples are given for a 7- and 51-pipe network, demonstrating the utility of the method. © 2009 ASCE.Aaron C. Zecchin, Angus R. Simpson, Martin F. Lambert, Langford B. White and John P. Vítkovsk

The central role of Italy in the spatial spread of USUTU virus in Europe

USUTU virus (USUV) is an arbovirus maintained in the environment through a bird-mosquito enzootic cycle. Previous surveillance plans highlighted the endemicity of USUV in North-eastern Italy. In this work, we sequenced 138 new USUV full genomes from mosquito pools (Culex pipiens) and wild birds collected in North-eastern Italy and we investigated the evolutionary processes (phylogenetic analysis, selection pressure and evolutionary time-scale analysis) and spatial spread of USUV strains circulating in the European context and in Italy, with a particular focus on North-eastern Italy. Our results confirmed the circulation of viruses belonging to four different lineages in Italy (EU1, EU2, EU3 and EU4), with the newly sequenced viruses from the North-eastern regions, Veneto and Friuli Venezia Giulia, belonging to the EU2 lineage and clustering into two different sub-lineages, EU2-A and EU2-B. Specific mutations characterize each European lineage and geographic location seem to have shaped their phylogenetic structure. By investigating the spatial spread in Europe, we were able to show that Italy acted mainly as donor of USUV to neighbouring countries. At a national level, we identified two geographical clusters mainly circulating in Northern and North-western Italy, spreading both northward and southward. Our analyses provide important information on the spatial and evolutionary dynamics of USUTU virus that can help to improve surveillance plans and control strategies for this virus of increasing concern for human health

Orthogonal methods based ant colony search for solving continuous optimization problems

Research into ant colony algorithms for solving continuous optimization problems forms one of the most significant and promising areas in swarm computation. Although traditional ant algorithms are designed for combinatorial optimization, they have shown great potential in solving a wide range of optimization problems, including continuous optimization. Aimed at solving continuous problems effectively, this paper develops a novel ant algorithm termed "continuous orthogonal ant colony" (COAC), whose pheromone deposit mechanisms would enable ants to search for solutions collaboratively and effectively. By using the orthogonal design method, ants in the feasible domain can explore their chosen regions rapidly and e±ciently. By implementing an "adaptive regional radius" method, the proposed algorithm can reduce the probability of being trapped in local optima and therefore enhance the global search capability and accuracy. An elitist strategy is also employed to reserve the most valuable points. The performance of the COAC is compared with two other ant algorithms for continuous optimization of API and CACO by testing seventeen functions in the continuous domain. The results demonstrate that the proposed COAC algorithm outperforms the others