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The electrophilic allergen screening assay (EASA) uses small-molecule probes as surrogates for skin proteins to measure hapten protein carrier complex formation, Key Event (KE) 1 in the adverse outcome pathway for skin sensitization. Although multiple assays are accepted for this purpose, the EASA has higher throughput and needs less specialized equipment than other commonly used KE1 assays. This validation study assessed transferability of the EASA to naïve laboratories and within- and between-laboratory reproducibility. The predictive capacity of the assay in relation to reference data both from the murine local lymph node assay (LLNA) and, where available, human predictive patch tests, was estimated. The validation study was conducted using performance standards developed for methods that are under evaluation for inclusion in relevant test guidelines. The within- and between-laboratory reproducibility were cumulatively 96% and 85%, respectively. These scores exceeded the performance standard thresholds of 80%. Compared to reference LLNA data, the cumulative EASA results from the four laboratories had an overall sensitivity of 87%, specificity of 76%, and accuracy of 83%. The consensus results among the four laboratories had an overall sensitivity of 85%, specificity of 80%, and accuracy of 83%. For human reference data, the cumulative EASA results had an overall sensitivity of 81%, specificity of 76%, and accuracy of 70%. The EASA predicted sensitizers very well, although it had a slightly higher rate of misclassifying some negative test chemicals as positive with a specificity below the performance standards criterion of 80%. Our findings support further exploring use of the EASA in defined approaches to identify potential skin sensitizers.

Petroleum hydrocarbons are potential sources of soil and water contamination. There are various clean-up technologies for removal of these crude spilled oil pollutants, such as microorganisms of different ecosystems. In the present study the capability of an autochthonous Rhodococcus ruber KE1, which was previously isolated from Persian Gulf water and sediment (Khark Island, south part of Iran), was evaluated for biodegradation of the contaminated seawater by Iranian exported heavy crude oil. In the crude oil biodegradation, both biotic and abiotic factors should be considered. So biotic factors such as growth curve of the Rhodococcus ruber KE1 have been studied. Results demonstrated that the maximum colony count was achieved to 9.50 × 109 cfu mL−1 after 26 h then reached to the death phase. The specific growth rate constant (μ) of the bacteria in logarithmic phase and mean generation times are calculated 0.10 h−1 and 3.02 h, respectively. Also different physical parameters such as pH, temperature, crude oil concentration, and agitation speed were optimized to achieve the maximum degradation efficiency. The best results were obtained at pH 8.5, temperature 40 °C, agitation speed of 250 rpm, and crude oil concentration 1% (v/v). The related data showed that Rhodococcus ruber KE1 in favourable conditions was able to degrade about 90% of total hydrocarbons after a week. The residual was analyzed for nitrogen- and sulfur-containing compounds using CHNS technique. Total nitrogen and sulfur were decreased 48 and 44%, respectively. The ability of this specific strain, as a surfactant producer was investigated under optimal conditions. A reduction in surface tension from 60 (control) to 26 mN/m was achieved. To the best of our knowledge, this is the first report of isolated Rhodococcus ruber KE1 from Persian Gulf, which has the ability to degrade crude oil and at the same time produce biosurfactant in a week’s time. The results indicated that autochthonous Rhodococcus ruber KE1 may be a good option to be utilized as a crude oil degrader.