Biological reduction of nitric oxide in aqueous Fe(II)EDTA solutions

The reduction of nitric oxide (NO) in aqueous solutions of Fe(II)EDTA is one of the core processes in BioDeNOx, an integrated physicochemical and biological technique for NO(x)() removal from industrial flue gases. NO reduction in aqueous solutions of Fe(II)EDTA (20-25 mM, pH 7.2 +/- 0.2) was investigated in batch experiments at 55 degrees C. Reduction of NO to N(2) was found to be biologically catalyzed with nitrous oxide (N(2)O) as an intermediate. Various sludges from full-scale denitrifying and anaerobic reactors were capable to catalyze NO reduction under thermophilic conditions. The NO reduction rate was not affected by the presence of ethanol or acetate. EDTA-chelated Fe(II) was found to be a suitable electron donor for the biological reduction of nitric oxide to N(2), with the concomitant formation of Fe(III)EDTA. In the presence of ethanol, EDTA-chelated Fe(III) was reduced to Fe(II)EDTA. This study strongly indicates that redox cycling of FeEDTA plays an important role in the biological denitrification process within the BioDeNOx concept.     

Mesophilic and thermophilic activated sludge post treatment of anaerobic effluent. Sludge and wastewater characterisation using batch experiments

Anaerobic pretreated paper process water was characterized interms of readily biodegradable, slowly biodegradable, very slowly biodegradable and inert wastewaterfractions under mesophilic and thermophilic conditions. The anaerobic pretreated paper process water containeda relatively high amount of slowly biodegradable components and few easily biodegradable componentsas indicated by the ratio of short term BOD over the BOD5. Wastewater readily biodegradable COD, determinedas short term BOD, was almost similar when measured under both temperature conditions. Fractions ofslowly biodegradable COD and inert COD of the same wastewater were found to depend on the type of biomassinvolved in the test. Thermophilic aerobic biomass was not able to degrade the wastewater to the sameextent as the mesophilic biomass resulting in higher apparent inert COD levels. Furthermore, wastewater colloidalCOD did not flocculate under thermophilic conditions and was thus not removed from the liquid phase.     

FERONIA receptor kinase interacts with S‐adenosylmethionine synthetase and suppresses S‐adenosylmethionine production and ethylene biosynthesis in Arabidopsis

Environmental inputs such as stress can modulate plant cell metabolism, but the detailed mechanism remains unclear. We report here that FERONIA (FER), a plasma membrane receptor‐like kinase, may negatively regulate the S‐adenosylmethionine (SAM) synthesis by interacting with two S‐adenosylmethionine synthases (SAM1 and SAM2). SAM participates in ethylene, nicotianamine and polyamine biosynthetic pathways and provides the methyl group for protein and DNA methylation reactions. The Arabidopsis fer mutants contained a higher level of SAM and ethylene in plant tissues and displayed a dwarf phenotype. Such phenotype in the fer mutants was mimicked by over‐expressing the S‐adenosylmethionine synthetase in transgenic plants, whereas sam1/2 double mutant showed an opposite phenotype. We propose that FER receptor kinase, in response to environmental stress and plant hormones such as auxin and BR, interacts with SAM synthases and down‐regulates ethylene biosynthesis.     

Tetranychus evansi spider mite populations suppress tomato defenses to varying degrees

Plant defense suppression is an offensive strategy of herbivores, in which they manipulate plant physiological processes to increase their performance. Paradoxically, defense suppression does not always benefit the defense‐suppressing herbivores, because lowered plant defenses can also enhance the performance of competing herbivores and can expose herbivores to increased predation. Suppression of plant defense may therefore entail considerable ecological costs depending on the presence of competitors and natural enemies in a community. Hence, we hypothesize that the optimal magnitude of suppression differs among locations. To investigate this, we studied defense suppression across populations of Tetranychus evansi spider mites, a herbivore from South America that is an invasive pest of solanaceous plants including cultivated tomato, Solanum lycopersicum, in other parts of the world. We measured the level of expression of defense marker genes in tomato plants after infestation with mites from eleven different T. evansi populations. These populations were chosen across a range of native (South American) and non‐native (other continents) environments and from different host plant species. We found significant variation at three out of four defense marker genes, demonstrating that T. evansi populations suppress jasmonic acid‐ and salicylic acid‐dependent plant signaling pathways to varying degrees. While we found no indication that this variation in defense suppression was explained by differences in host plant species, invasive populations tended to suppress plant defense to a smaller extent than native populations. This may reflect either the genetic lineage of T. evansi—as all invasive populations we studied belong to one linage and both native populations to another—or the absence of specialized natural enemies in invasive T. evansi populations.     

Global crop improvement networks to bridge technology gaps

To ensure future food security, there is an urgent need for improved co-ordination of agricultural research. While advances in biotechnology hold considerable promise, significant technology gaps exist that may reduce their impact. Examples include an incomplete knowledge of target breeding environments, a limited understanding and/or application of optimal crop management practices, and underfunded extension services. A better co-ordinated and more globalized approach to agricultural research through the implementation of Global Crop Improvement Networks (GCIN) is proposed. Such networks could underpin agricultural research and development by providing the following types of services: (i) increased resolution and precision of environmental information, including meteorological data, soil characteristics, hydrological data, and the identification of environmental 'hotspots' for a range of biotic, abiotic, and socio-economic constraints; (ii) augmented research capacity, including network-based variety and crop management trials, faster and more comprehensive diagnosis of emerging constraints, timely sharing of new technologies, opportunities to focus research efforts better by linking groups with similar productivity constraints and complementary skills, and greater control of experimental variables in field-based phenotyping; and (iii) increased communication and impacts via more effective dissemination of new ideas and products, the integration of information globally to elicit well-timed local responses to productivity threats, an increased profile, and the publicity of threats to food security. Such outputs would help target the translation of research from the laboratory into the field while bringing the constraints of rural communities closer to the scientific community. The GCIN could provide a lens which academia, science councils, and development agencies could use to focus in on themes of common interest, and working platforms to integrate novel research approaches on crop adaptation and rural development.     

Safeguarding bacterial resources promotes biotechnological innovation

Environmental research delivers valuable bacterial resources for biotechnology. We believe that systematic long-term preservation of bacteria will promote future biotechnological innovations, by safeguarding the accessibility of bacteria already recognized to have interesting features and providing a “pool” of bacterial resources for novel applied research. To this end, we want to advocate the incorporation of preservation tests in environmental or applied microbiological research. This paper introduces non-specialists to different preservation methods for bacteria. Several parameters that influence long-term storage of bacterial resources are explained and practical tips and guidelines are formulated. Also, the vital role of public culture collections is highlighted and the state-of-the-art of preservation of non-pure cultures is described.     

Toward a global phylogeny of the "living fossil" crustacean order of the Notostraca

Tadpole shrimp (Crustacea, Notostraca) are iconic inhabitants of temporary aquatic habitats worldwide. Often cited as prime examples of evolutionary stasis, surviving representatives closely resemble fossils older than 200 mya, suggestive of an ancient origin. Despite significant interest in the group as 'living fossils' the taxonomy of surviving taxa is still under debate and both the phylogenetic relationships among different lineages and the timing of diversification remain unclear. We constructed a molecular phylogeny of the Notostraca using model based phylogenetic methods. Our analyses supported the monophyly of the two genera Triops and Lepidurus, although for Triops support was weak. Results also revealed high levels of cryptic diversity as well as a peculiar biogeographic link between Australia and North America presumably mediated by historic long distance dispersal. We concluded that, although some present day tadpole shrimp species closely resemble fossil specimens as old as 250 mya, no molecular support was found for an ancient (pre) Mesozoic radiation. Instead, living tadpole shrimp are most likely the result of a relatively recent radiation in the Cenozoic era and close resemblances between recent and fossil taxa are probably the result of the highly conserved general morphology in this group and of homoplasy.     

Structural and thermodynamic characterization of the Escherichia coli RelBE toxin-antitoxin system: indication for a functional role of differential stability

The RelE and RelB proteins constitute the RNA interferase (toxin) and its cognate inhibitor (antitoxin) components of the Escherichia coli relBE toxin-antitoxin system. Despite the well-described functionality and physiological activity of this system in E. coli, no structural study was performed on the folding and stability of the protein pair in solution. Here we structurally and thermodynamically characterize the RelBE system components from E. coli in solution, both separately and in their complexed state. The RelB antitoxin, an alpha-helical protein according to circular dichroism and infrared spectroscopy, forms oligomers in solution, exhibits high thermostability with a TM of 58.5 degrees C, has a considerable heat resistance, and has high unfolding reversibility. In contrast, the RelE toxin includes a large portion of antiparallel beta-sheets, displays lower thermostability with a TM of 52.5 degrees C, and exhibits exceptional sensitivity to heat. Complex formation, accompanied by a structural transition, leads to a 12 degrees C increase in the TM and substantial heat resistance. Moreover, in vivo interaction and protein footprint experiments indicate that the C-terminal part of RelB is responsible for RelB-RelE interaction, being protease sensitive in its free state, while it becomes protected from proteolysis when complexed with RelE. Overall, our findings support the notion that RelB lacks a well-organized hydrophobic core in solution whereas RelE is a well-folded protein. Furthermore, our results support that RelB protein from E. coli is similar to ParD and CcdA antitoxins in both fold and thermodynamic properties. The differential folding state of the proteins is discussed in the context of their physiological activities.