The impact of fluazaindolizine on free-living nematodes and the nematode community structure in a root-knot nematode infested vegetable production system.

Background: Fluazaindolizine is a novel sulfonamide nematicide that is currently under commercialization in various countries. Four trials (two in tomato, two in zucchini) were carried out over two growing seasons in a root-knot nematode (RKN; Meloidogyne incognita)-infested plastic house to test the effects of a single application of fluazaindolizine at 1000 and 2000 g ha , on RKN, the resident nematode community and to estimate any side effects on the soil food web and soil ecological functions. The composition of the nematode community was evaluated at three sampling times, pre-treatment (before soil preparation), at planting (after nematicide application) and at harvest.

Suitability of Zucchini and Cucumber Genotypes to Populations of Meloidogyne arenaria, M. incognita, and M. javanica.

The host suitability of five zucchini and three cucumber genotypes to Meloidogyne incognita (MiPM26) and M. javanica (Mj05) was determined in pot experiments in a greenhouse. The number of egg masses (EM) did not differ among the genotypes of zucchini or cucumber, but the eggs/plant and reproduction factor (Rf) did slightly.

Experimental validation of Haldane's hypothesis on the role of infection as an evolutionary force for Metazoans.

A common drawback in evolutionary science is the fact that the evolution of organisms occurs in geological timing, completely out of the time scale of laboratory experimental work. For this reason, some relevant hypotheses on evolution of Metazoans are based on correlations more than on experimental data obtained for testing the robustness of those hypotheses. In the current work, we implement an experimental methodology to analyze the role of infections as a driving force in the evolution of Metazoans (Haldane's hypothesis).

Hydrodynamic characterization of the DEAD-box RNA helicase DbpA.

The Escherichia coli DEAD-box protein A (DbpA) belongs to the highly conserved superfamily-II of nucleic acid helicases that play key roles in RNA metabolism. A central question regarding helicase activity is whether the process of coupling ATP hydrolysis to nucleic acid unwinding requires an oligomeric form of the enzyme. We have investigated the structural and functional properties of DbpA by multi-angle laser light-scattering, size-exclusion chromatography, analytical ultracentrifugation, chemical cross-linking and hydrodynamic modeling.

Effects of DL-methionine on hatching and activity of Meloidogyne incognita eggs and juveniles.

Several concentrations of DL-methionine were tested in the laboratory for their effects on Meloidogyne incognita (Kofoid & White) Chitwood egg hatching and juvenile activity in aqueous suspensions and infested soil. After 7 days in methionine solutions, the proportions of hatched eggs were reduced by 23.3% at 0.

Equilibrium and kinetic analysis of nucleotide binding to the DEAD-box RNA helicase DbpA.

The Escherichia coli DEAD-box protein A (DbpA) is an RNA helicase that utilizes the energy from ATP binding and hydrolysis to facilitate structural rearrangements of rRNA. We have used the fluorescent nucleotide analogues, mantADP and mantATP, to measure the equilibrium binding affinity and kinetic mechanism of nucleotide binding to DbpA in the absence of RNA. Binding generates an enhancement in mant-nucleotide fluorescence and a corresponding reduction in intrinsic DbpA fluorescence, consistent with fluorescence resonance energy transfer (FRET) from DbpA tryptophan(s) to bound nucleotides.