Phylogenetic evidence for the invasion of a commercialized European Phasmarhabditis hermaphrodita lineage into North America and New Zealand

Biological control (biocontrol) as a component of pest management strategies reduces reliance on synthetic chemicals, and seemingly offers a natural approach that minimizes environmental impact. However, introducing a new organism to new environments as a classical biocontrol agent can have broad and unanticipated biodiversity effects and conservation consequences. Nematodes are currently used in a variety of commercial biocontrol applications, including the use of Phasmarhabditis hermaphrodita as an agent targeting pest slug and snail species. This species was originally discovered in Germany, and is generally thought to have European origins. P. hermaphrodita is sold under the trade name Nemaslug®, and is available only in European markets. However, this nematode species was discovered in New Zealand and the western United States, though its specific origins remained unclear. In this study, we analyzed 45 nematode strains representing eight different Phasmarhabditis species, collected from nine countries around the world. A segment of nematode mitochondrial DNA (mtDNA) was sequenced and subjected to phylogenetic analyses. Our mtDNA phylogenies were overall consistent with previous analyses based on nuclear ribosomal RNA (rRNA) loci. The recently discovered P. hermaphrodita strains in New Zealand and the United States had mtDNA haplotypes nearly identical to that of Nemaslug®, and these were placed together in an intraspecific monophyletic clade with high support in maximum likelihood and Bayesian analyses. We also examined bacteria that co-cultured with the nematode strains isolated in Oregon, USA, by analyzing 16S rRNA sequences. Eight different bacterial genera were found to associate with these nematodes, though Moraxella osloensis, the bacteria species used in the Nemaslug® formulation, was not detected. This study provided evidence that nematodes deriving from the Nemaslug® biocontrol product have invaded countries where its use is prohibited by regulatory agencies and not commercially available

Antiseptics and Disinfectants

Antiseptics and disinfectants (see definitions) share common skin side effects, i.e., irritation, allergic contact dermatitis, and eventually immunological contact urticaria. Some antiseptics fall into disuse, due to their lack of efficacy (dyes) or their strong allergic properties (mercurials), except thiomersal, the indications of which remain important. Current antiseptics (i.e., povidone-iodine or chlorhexidine) are of great importance, due to the emergence of MRSA and CA-MRSA, leading to a decrease in the use of topical antibiotics to which Gram-positive and Gram-negative bacteria are more and more resistant. Silver-based wound and burn dressings may lead to new cases of allergic contact dermatitis, mainly related to the incorporation of new antiseptics, such as octenidine or PHMB. Disinfectants are a common source of occupational irritant and/or allergic contact dermatitis. Aldehydes are widely used as disinfectants. Formaldehyde, glutaraldehyde, and glyoxal are responsible for many cases of allergic contact dermatitis. Quaternary ammonium compounds, and particularly benzalkonium chloride, are disinfectants provoking irritant and/or allergic contact dermatitis. The interpretation of patch tests is difficult, and the use of ROATs is advised

Electron Paramagnetic Resonance Spectroscopy of Nitroxide-Labeled Calmodulin

Calmodulin (CaM) is a highly conserved calcium-binding protein consisting of two homologous domains, each of which contains two EF-hands, that is known to bind well over 300 proteins and peptides. In most cases the (Ca(2+))(4)-form of CaM leads to the activation of a key regulatory enzyme or protein in a myriad of biological processes. Using the nitroxide spin-labeling reagent, 3-(2-iodoacetamido)-2,2,5,5-tetramethyl-1-pyrrolidinyl oxyl, bovine brain CaM was modified at 2-3 methionines with retention of activity as judged by the activation of cyclic nucleotide phosphodiesterase. X-band electron paramagnetic resonance (EPR) spectroscopy was used to measure the spectral changes upon addition of Ca(2+) to the apo-form of spin-labeled protein. A significant loss of spectral intensity, arising primarily from reductions in the heights of the low, intermediate, and high field peaks, accompanied Ca(2+) binding. The midpoint of the Ca(2+-)mediated transition determined by EPR occurred at a higher Ca(2+) concentration than that measured with circular dichroic spectroscopy and enzyme activation. Recent data have indicated that the transition from the apo-state of CaM to the fully saturated form, [Ca(2+))(4)-CaM], contains a compact intermediate corresponding to [Ca(2+))(2)-CaM], and the present results suggest that the spin probes are reporting on Ca(2+) binding to the last two sites in the N-terminal domain, i.e. for the [Ca(2+))(2)-CaM] → [Ca(2+))(4)-CaM] transition in which the compact structure becomes more extended. EPR of CaM, spin-labeled at methionines, offers a different approach for studying Ca(2+)-mediated conformational changes and may emerge as a useful technique for monitoring interactions with target proteins