Enzymes in the ergosterol-biosynthetic pathway are the targets of a number of antifungal agents including azoles, allylamines, and morpholines. In order to understand the response of Saccharomyces cerevisiae to perturbations in the ergosterol pathway, genome-wide transcript profiles following exposure to a number of antifungal agents targeting ergosterol biosynthesis (clotrimazole, fluconazole, itraconazole, ketoconazole, voriconazole, terbinafine, and amorolfine) were obtained. These profiles were compared to the transcript profiles of strains containing deletions of one of the late-stage ergosterol genes: ERG2, ERG5, or ERG6. A total of 234 genes were identified as responsive, including the majority of genes from the ergosterol pathway. Expression of several responsive genes, including ERG25, YER067W, and YNL300W, was also monitored by PCR over time following exposure to ketoconazole. The kinetics of transcriptional response support the conditions selected for the microarray experiment. In addition to ergosterol-biosynthetic genes, 36 mitochondrial genes and a number of other genes with roles related to ergosterol function were responsive, as were a number of genes responsive to oxidative stress. Transcriptional changes related to heme biosynthesis were observed in cells treated with chemical agents, suggesting an additional effect of exposure to these compounds. The expression profile in response to a novel imidazole, PNU-144248E, was also determined. The concordance of responsive genes suggests that this compound has the same mode of action as other azoles. Thus, genome-wide transcript profiles can be used to predict the mode of action of a chemical agent as well as to characterize expression changes in response to perturbation of a metabolic pathway.

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Background -Interleukin-31 (IL-31) is a member of the gp130 ⁄ interleukin-6 cytokine family that is produced by cell types such as T helper 2 lymphocytes and cutaneous lymphocyte antigen positive skin homing T cells. When overexpressed in transgenic mice, IL-31 induces severe pruritus, alopecia and skin lesions. In humans, IL-31 serum levels correlate with the severity of atopic dermatitis in adults and children.Hypothesis ⁄ Objective -To determine the role of IL-31 in canine pruritus and naturally occurring canine atopic dermatitis (AD).Animals -Purpose-bred beagle dogs were used for laboratory studies. Serum samples were obtained from laboratory animals, nondiseased client-owned dogs and client-owned dogs diagnosed with naturally occurring AD.Methods -Purpose-bred beagle dogs were administered canine interleukin-31 (cIL-31) via several routes (intravenous, subcutaneous or intradermal), and pruritic behaviour was observed ⁄ quantified via video monitoring. Quantitative immunoassay techniques were employed to measure serum levels of cIL-31 in dogs.Results -Injection of cIL-31 into laboratory beagle dogs caused transient episodes of pruritic behaviour regardless of the route of administration. When evaluated over a 2 h period, dogs receiving cIL-31 exhibited a significant increase in pruritic behaviour compared with dogs that received placebo. In addition, cIL-31 levels were detectable in 57% of dogs with naturally occurring AD ( ‡13 pg ⁄ mL) but were below limits of quantification (<13 pg ⁄ mL) in normal, nondiseased laboratory or client-owned animals.Conclusions -Canine IL-31 induced pruritic behaviours in dogs. Canine IL-31 was detected in the majority of dogs with naturally occurring AD, suggesting that this cytokine may play an important role in pruritic allergic skin conditions, such as atopic dermatitis, in this species.

QPT-1 was discovered in a compound library by high-throughput screening and triage for substances with whole-cell antibacterial activity. This totally synthetic compound is an unusual barbituric acid derivative whose activity resides in the (؊)-enantiomer. QPT-1 had activity against a broad spectrum of pathogenic, antibioticresistant bacteria, was nontoxic to eukaryotic cells, and showed oral efficacy in a murine infection model, all before any medicinal chemistry optimization. Biochemical and genetic characterization showed that the QPT-1 targets the ␤ subunit of bacterial type II topoisomerases via a mechanism of inhibition distinct from the mechanisms of fluoroquinolones and novobiocin. Given these attributes, this compound represents a promising new class of antibacterial agents. The success of this reverse genomics effort demonstrates the utility of exploring strategies that are alternatives to target-based screens in antibacterial drug discovery.

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