Pavement ant extract is a chemotaxis repellent for C. elegans.

Ant behavior relies on a collection of natural products, from following trail pheromones during foraging to warding off potential predators. How nervous systems sense these compounds to initiate a behavioral response remains unclear. Here, we used Caenorhabditis elegans chemotaxis assays to investigate how ant compounds are detected by heterospecific nervous systems. We found that C. elegans avoid extracts of the pavement ant ( Tetramorium immigrans ) and either osm-9 or tax-4 ion channels are required for this response. These experiments were conducted in an undergraduate laboratory course, demonstrating that new insights into interspecies interactions can be generated through genuine research experiences in a classroom setting.

Targeting an inflammation-amplifying cell population can attenuate osteoarthritis-associated pain.

BACKGROUND: Understanding of pain in osteoarthritis, its genesis, and perception is still in its early stages. Identification of precise ligand-receptor pairs that transduce pain and the cells and tissues in which they reside will elucidate new therapeutic approaches for pain management. Our recent studies had identified an inflammation-amplifying (Inf-A) cell population that is expanded in human OA cartilage and is distinctive in the expression of both IL1R1 and TNF-R2 receptors and active Jnk signaling cascade. METHODS: In this study, we have tested the function of the cartilage-resident IL1R1+TNF-R2+ Inf-A cells in OA. We have identified that the IL1R1+TNF-R2+ Inf-A cells expand in aged mice as well as after anterior cruciate ligament tear upon tibia loading and OA initiation in mice. We targeted and modulated the Jnk signaling cascade in InfA through competitive inhibition of Jnk signaling in mice and human OA explants and tested the effects on joint structure and gait in mice. RESULTS: Modulation of Jnk signaling led to attenuation of inflammatory cytokines CCL2 and CCL7 without showing any structural improvements in the joint architecture. Interestingly, Jnk inhibition and lowered CCL2 and 7 are sufficient to significantly improve the gait parameters in treated PTOA mice demonstrating reduced OA-associated pain. Consistent with the mice data, treatment with JNK inhibitor did not improve human OA cartilage explants. CONCLUSION: These studies demonstrate that Inf-A, an articular-cartilage resident cell population, contributes to pain in OA via secretion of CCL2 and 7 and can be targeted via inhibition of Jnk signaling.

Attic dust assessment near a wood treatment plant: past air pollution and potential exposure.

The wood treatment process uses substances that generate hazardous compounds that may contaminate environmental compartments. In the present study, an area under influence of a deactivated wood treatment plant was investigated to evaluate past air pollution and to try to understand local air dispersion. Attic dust samples were collected from eight residences around the plant and from two residences outside this area, as reference samples. The presence of copper, chromium, arsenic, pentachlorophenol, sixteen priority polycyclic aromatic hydrocarbons and mutagenic activity using Salmonella/microsome assay was evaluated. The residences close to the entrance to the plant were the most affected, according to potentially toxic elements analysis. The PCP concentration was 0.49 mg/kg and the total PAHs content ranged from 0.40 to 13.31 µg/g with greater dispersion than potentially toxic elements. The highest mutagenesis values were 15,905 and 10,399 revertants/g of dust in the absence and presence of S9 mix (mammalian metabolic activation), respectively. Samples in which the total PAHs concentration was less than 2 µg/g no mutagenic effects were observed, including the residences in the reference area. The contribution of PAHs to mutagenesis was 10 percent, indicating that other compounds may contribute to the mutagenic effect. These results suggest that the population was or is potentially exposed to substances with strong effects on health.

Quantitative 1H NMR-analysis of technical octabrominated diphenylether DE-79 and UV spectra of its components and photolytic transformation products.

A quantitative analysis of the technical octabromo diphenylether mixture DE-79 is performed by (1)H NMR, avoiding any separation technique. The mass fractions are 36% BDE183, 19% BDE197, 13.1% BDE207, 9.1% BDE196, 7.3% BDE153, 6.2% BDE203, 2.2% BDE180, 1.6% BDE171, 1.2% BDE154 and 0.7% BDE206, considering an additional mass fraction of 1.3% BDE209 determined by HPLC analysis with a diode array detector (DAD). HPLC chromatograms of the BDEs in commercial decaBDE, octaBDE DE-79 and pentaBDE DE-71 and UV spectra of the components of DE-79 are presented. The photolysis of the octaBDE mixture DE-79, dissolved in tetrahydrofuran, by simulated sunlight is monitored by HPLC-DAD and observed to proceed mainly via debromination. Polybrominated dibenzofurans are identified from their UV spectra as significant intermediates.

Evaluation of zirconocene-based silica phases in organochloride pesticides preconcentration.

Silica was chemically modified with zirconocenes, namely Cp(2)ZrCl(2), (MeCp)(2)ZrCl(2), (iBuCp)(2)ZrCl(2) and (nBuCp)(2)ZrCl(2) by grafting. Hybrid silica bearing surface indene groups was synthesized by the sol-gel method, followed by metallation with ZrCl(4)2THF. According to RBS measurements, metal content was 0.2-0.3 wt% Zr/SiO(2) for the grafted systems and 4.5 wt% Zr/SiO(2) for the phase prepared by the sol-gel method. The solid phases were evaluated in the adsorption/preconcentration of organochloride (hexachlorobenzene, lindane, heptachlor, heptachlor epoxide, dieldrin and endrin) pesticides from aqueous solution. For comparative reasons, commercial LC-18 phase was also evaluated. Analyte concentration was monitored by GC-ECD. For the grafted phases, the coordination sphere around the metal center seems not to influence the adsorption/desorption properties of these phases vis-à-vis the studied analytes. Recoveries results for both analytes were comparable to those observed in the case of LC-18 in the case of the phases prepared by the sol-gel method. Experiments using ZrO(2) and ZrO(2)/SiO(2) phases led to lower recovery results.

Synthesis of zirconocene-based silica phases and evaluation in lindane and heptachlor epoxide adsorption/desorption.

Silica (350 m(2) g(-1)) was chemically modified with Cp2ZrCl2 and (nBuCp)2ZrCl2 by grafting. Hybrid silica bearing surface indene groups was synthesized by the sol-gel method, followed by metallation with ZrCl(4)2THF. The resulting phases were characterized by Rutherford backscattering spectrometry (RBS), 13C and 29Si magic angle spin nuclear magnetic resonance, X-ray photoelectron spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy. According to RBS measurements, metal content was 0.2- to 0.3-wt% Zr/SiO2 for the grafted systems and 4.5-wt% Zr/SiO2 for the phase prepared by the sol-gel method. The solid phases were evaluated for the adsorption/preconcentration of lindane and heptachlor epoxide from aqueous solution. For comparative reasons, the commercial LC-18 phase was also evaluated. Analyte concentration was monitored by gas chromatography electron capture detection. For the grafted phases, the coordination sphere around the metal center seems not to influence the adsorption/desorption properties of these phases vis-a-vis the studied analytes. In the case of the phases prepared by the sol-gel method, recovery results were comparable to those observed for LC-18. Experiments using ZrO2 and ZrO2/SiO2 phases led to lower recovery results.