Flowers of the hop plant provide both bitterness and “hoppy” flavor to beer. Hops are, however, both a water and energy intensive crop and vary considerably in essential oil content, making it challenging to achieve a consistent hoppy taste in beer. Here, we report that brewer’s yeast can be engineered to biosynthesize aromatic monoterpene molecules that impart hoppy flavor to beer by incorporating recombinant DNA derived from yeast, mint, and basil. Whereas metabolic engineering of biosynthetic pathways is commonly enlisted to maximize product titers, tuning expression of pathway enzymes to affect target production levels of multiple commercially important metabolites without major collateral metabolic changes represents a unique challenge. By applying state-of-the-art engineering techniques and a framework to guide iterative improvement, strains are generated with target performance characteristics. Beers produced using these strains are perceived as hoppier than traditionally hopped beers by a sensory panel in a double-blind tasting.
A quantitative assay for urinary propranolol and six of its unconjugated metabolites by a gas chromatography mass spectrometry computer system has been developed. Conjugated metabolites are also determined following enzyme hydrolysis. These compounds are separated from murine by Amberlite XAD-2 resin column chromatography and are converted to methyl esters and trifluoroacetyl derivatives. Each substance is quantitated from reconstructed ion chromatograms using a specific mass or sum of masses for each compound by comparing its area with that of an appropriate internal standard. The minimum detectable concentrations are in the range of 50--100 ng ml-1. The calibrations are linear from 0.10--15.0 microgram ml-1 with recoveries ranging from 62--91%. This procedure yields a high degree of specificity, selectivity and reproducibility, as demonstrated by the analyses of urine from dogs receiving single 40 mg doses of propranolol orally.
Introduction: Acne is a chronic inflammatory disorder of the pilosebaceous unit with differential pathogenesis. To elucidate the roles of hormones in acne pathogenesis, we conducted a study to evaluate the serum testosterone, estradiol, progesterone levels in women with acne vulgaris. Methods: We conducted a cross-sectional descriptive study, and 175 women with acne vulgaris were examined; their serum estradiol, progesterone, testosterone were analyzed by chemiluminescence technique and compared with the healthy control group. Results: Increased serum hormone levels in women with acne vulgaris were accounted for 29.7%, and hyperandrogenism was accounted for 16.0% of cases. We found significant differences in testosterone levels (mean value, 55.67±25.56 versus 38.37±10.16 ng/dL, p<0.05) respectively in the acne group and the control group. However, the estradiol level of the acne group (323.15±93.31 pmol/L) was lower than the control group (370.94±58.88 pmol/L) with p<0.05). No statistically significant differences were found for progesterone (0.60±0.38 versus 0.50±0.15 ng/mL, p>0.05) levels. Moreover, we did not find the relationship between serum hormone levels and the severity of acne vulgaris. Conclusion: This study showed that the female acne vulgaris patients may have high serum testosterone levels and low serum estradiol levels compared with those of female controls. However, hormone alterations had no correlation with the acne grades.
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