REXIB: Remote Experiments Interface Builder

Remote Experimentation is an educational resource that allows teachers to strengthen the practical contents of science & engineering courses. However, building up the interfaces to remote experiments is not a trivial task. Although teachers normally master the practical contents addressed by a particular remote experiment they usually lack the programming skills required to quickly build up the corresponding web interface. This paper describes the automatic generation of experiment interfaces through a web-accessible Java application. The application displays a list of existent modules and once the requested modules have been selected, it generates the code that enables the browser to display the experiment interface. The tools main advantage is enabling non-tech teachers to create their own remote experiments

Lipid-free Antigen B subunits from echinococcus granulosus: oligomerization, ligand binding, and membrane interaction properties

Background: The hydatid disease parasite Echinococcus granulosus has a restricted lipid metabolism, and needs to harvest essential lipids from the host. Antigen B (EgAgB), an abundant lipoprotein of the larval stage (hydatid cyst), is thought to be important in lipid storage and transport. It contains a wide variety of lipid classes, from highly hydrophobic compounds to phospholipids. Its protein component belongs to the cestode-specific Hydrophobic Ligand Binding Protein family, which includes five 8-kDa isoforms encoded by a multigene family (EgAgB1-EgAgB5). How lipid and protein components are assembled into EgAgB particles remains unknown. EgAgB apolipoproteins self-associate into large oligomers, but the functional contribution of lipids to oligomerization is uncertain. Furthermore, binding of fatty acids to some EgAgB subunits has been reported, but their ability to bind other lipids and transfer them to acceptor membranes has not been studied.<p></p> Methodology/Principal Findings: Lipid-free EgAgB subunits obtained by reverse-phase HPLC were used to analyse their oligomerization, ligand binding and membrane interaction properties. Size exclusion chromatography and cross-linking experiments showed that EgAgB8/2 and EgAgB8/3 can self-associate, suggesting that lipids are not required for oligomerization. Furthermore, using fluorescent probes, both subunits were found to bind fatty acids, but not cholesterol analogues. Analysis of fatty acid transfer to phospholipid vesicles demonstrated that EgAgB8/2 and EgAgB8/3 are potentially capable of transferring fatty acids to membranes, and that the efficiency of transfer is dependent on the surface charge of the vesicles.<p></p> Conclusions/Significance: We show that EgAgB apolipoproteins can oligomerize in the absence of lipids, and can bind and transfer fatty acids to phospholipid membranes. Since imported fatty acids are essential for Echinococcus granulosus, these findings provide a mechanism whereby EgAgB could engage in lipid acquisition and/or transport between parasite tissues. These results may therefore indicate vulnerabilities open to targeting by new types of drugs for hydatidosis therapy.<p></p&gt

Isolation and properties of a pure bacterial strain capable of fluorobenzene degradation as sole carbon and energy source

A pure bacterial strain capable of aerobic biodegradation of fluorobenzene (FB) as the sole carbon and energy source was isolated by selective enrichment from sediments collected from a polluted site. 16S rRNA and fatty acid analyses support that strain F11 belongs to a novel genus within the a-2 subgroup of the Proteobacteria, possibly within a new clade related to the order Rhizobiales. In batch cultures, growth of strain F11 on FB led to stoichiometric release of fluoride ion. Maximum experimental growth rate of 0.04 h-1 was obtained at FB concentration of 0.4 mM. Growth kinetics were described by the Luong model. An inhibitory effect with increasing FB concentrations was observed, with no growth occurring at concentrations higher than 3.9 mM. Strain F11 was shown to be able to use a range of other organic compounds, including other fluorinated compounds such as 2-fluorobenzoate, 4-fluorobenzoate and 4-fluorophenol. To our knowledge, this is the first time biodegradation of FB, as the sole carbon and energy source, by a pure bacterium has been reported

Isolation and identification of microbial populations from an odour treating biofilter

Complex odour emissions are normally associated to the operation of wastewater treatment plants, composting facilities and agro-industry activities. The most common contaminants are hydrogen sulfide (H2S), organic reduced sulfur compounds (e.g.,CH3SH), and volatile organic compounds (VOCs). These compounds can be treated using biological air treatment systems, such as biofilters. Five different types of material, including pieces of wood and polymeric material, were collected from different locations of a biofilter treating odours at an organic waste treatment plant and subjected to microbiological characterization. Colony forming units (CFU/g) ranged from 107 to 108 CFU/g from each different material analyzed. The different materials showed high heterogeneity of microbial colonization, being the diversity higher in a heather based material. After random amplification of polymorphic DNA (RAPD) analysis, a total of 22 different isolates were identified by 16S rRNA sequencing analysis. Ten isolates demonstrated capacity to grow on solid sulphur oxidizing medium. Their capacity to oxidize sulphur compounds in liquid medium is being further studied

Biological treatment of a contaminated gaseous emission containing monochlorobenzene

This study presents the operation of a biotrickling filter when treating a monochlorobenzene (MCB) contaminated gaseous emission. Treatment dynamics were characterised by exposing the reactor to various MCB Organic Loads (OL). The use of different growth support materials, namely limestone, sand, ceramic and PVC pall-rings, was investigated. Limestone led to clogging of the reactor due to the accumulation of surface precipitates, but PVC pall-rings allowed for a uniform biofilm growth. The biotrickling filter presented maximum removal efficiency (RE, 95%) under OL regimes of 10 g m-3-reactor h-1. Treatment inhibition was observed when the reactor was exposed to OL of 45 g m-3-reactor h-1 with RE reaching a minimum value (8%) and elimination capacity of 8 g m3-reactor h-1 The first half of the reactor height was the predominant section for MCB biodegradation and increasing the mineral medium redrculation rate was beneficial for the overall treatment