Multi-laboratory Validation of a New Marine Biodegradation Screening Test for Chemical Persistence Assessment.

Current biodegradation screening tests are not specifically designed for persistence assessment of chemicals, often show high inter- and intra-test variability, and often give false negative biodegradation results. Based on previous studies and recommendations, an international ring test involving 13 laboratories validated a new test method for marine biodegradation with a focus on improving the reliability of screening to determine the environmental degradation potential of chemicals. The new method incorporated increased bacterial cell concentrations to better represent the microbial diversity; a chemical is likely to be exposed in the sampled environments and ran beyond 60 days, which is the half-life threshold for chemical persistence in the marine environment.

Proteomic sample preparation by microdialysis: easy, speedy, and nonselective.

Microdialysis tools have been developed for parallelized medium exchange designated for sample volumes from 10 to 100 μl, compatible with the microplate format, and guaranteeing maximum recoveries without selectivity. These tools are applicable to both protein and peptide analysis. Moreover, they may be used for binding studies as well as for reconcentration and as unique sample containers for complex operating sequences allowing contemporaneous processing and high throughput.

Functional characterization of a class III acid endochitinase from the traps of the carnivorous pitcher plant genus, Nepenthes.

Carnivory in plants is an adaptation strategy to nutrient-poor environments and soils. Carnivorous plants obtain some additional mineral nutrients by trapping and digesting prey; the genus Nepenthes is helped by its specialized pitcher traps. To make the nutrients available, the caught prey needs to be digested, a process that requires the concerted activity of several hydrolytic enzymes.

Alamethicin-induced electrical long distance signaling in plants.

Systemic signals induced by wounding and/or pathogen or herbivore attack may be realized by either chemical or mechanical signals. In plants a variety of electrical phenomena have been described and may be considered as signal-transducing events; such as variation potentials (VPs) and action potentials (APs) which propagate over long distances and hence are able to carry information from organ to organ. In addition, we recently described a new type of electrical long-distance signal that propagates systemically, i.

System potentials, a novel electrical long-distance apoplastic signal in plants, induced by wounding.

Systemic signaling was investigated in both a dicot (Vicia faba) and a monocot (Hordeum vulgare) plant. Stimuli were applied to one leaf (S-leaf), and apoplastic responses were monitored on a distant leaf (target; T-leaf) with microelectrodes positioned in substomatal cavities of open stomata. Leaves that had been injured by cutting and to which a variety of cations were subsequently added caused voltage transients at the T-leaf, which are neither action potentials nor variation potentials: with respect to the cell interior, the initial polarity of these voltage transients is hyperpolarizing; they do not obey the all-or-none rule but depend on both the concentration and the type of substance added and propagate at 5 to 10 cm min(-1).

The coupling ion in the methanoarchaeal ATP synthases: H(+) vs. Na(+) in the A(1)A(o) ATP synthase from the archaeon Methanosarcina mazei Gö1.

To establish a system to analyze ATP synthesis by the archaeal A(1)A(o) ATP synthase and to address the nature of the coupling ion, the operon encoding the A(1)A(o) ATP synthase from the mesophile Methanosarcina mazei Gö1 was cloned in an expression vector and it was expressed in the F(1)F(o) ATP synthase-negative mutant Escherichia coli DK8. Western blot analyses revealed that each of the subunits was produced, and the subunits assembled to a functional, membrane-embedded ATP synthase/ATPase. ATP hydrolysis was inhibited by dicyclohexylcarbodiimide but also by tributyltin, which turned out to be the most efficient inhibitor of the A(o) domain of A(1)A(o) ATP synthase known to date.

Oral secretions from herbivorous lepidopteran larvae exhibit ion channel-forming activities.

Feeding insects introduce oral secretions (OS) into the wounded tissue of the attacked plant. Various OS-derived molecules must be involved in subsequent processes including the induction of plant defence reactions. Using the planar lipid bilayer membrane technique, isolated OS were analyzed with respect to their membrane activities.