Engineering Pseudomonas aeruginosa arylsulfatase for hydrolysis of α-configured steroid sulfates.

Steroid sulfate esters are important metabolites for anti-doping efforts in sports, pathology and research. Analysis of these metabolites is facilitated by hydrolysis using either acid or enzymatic catalysis. Although enzymatic hydrolysis is preferred for operating at neutral pH, no known enzyme is capable of hydrolyzing all steroid sulfate metabolites.

Evolving a lipase for hydrolysis of natural triglycerides along with enhanced tolerance towards a protease and surfactants.

In the accompanying paper, we described evolving a lipase to the point where variants were soluble, stable and capable of degrading C8 TAG and C8 esters. These variants were tested for their ability to survive in an environment that might be encountered in a washing machine. Unfortunately, they were inactivated both by treatment with a protease used in laundry detergents and by very low concentrations of sodium dodecyl sulfate (SDS).

Epiandrosterone sulfate prolongs the detectability of testosterone, 4-androstenedione, and dihydrotestosterone misuse by means of carbon isotope ratio mass spectrometry.

In the course of investigations into the metabolism of testosterone (T) by means of deuterated T and hydrogen isotope ratio mass spectrometry, a pronounced influence of the oral administration of T on sulfoconjugated steroid metabolites was observed. Especially in case of epiandrosterone sulfate (EPIA_S), the contribution of exogenous T to the urinary metabolite was traceable up to 8 days after a single oral dose of 40 mg of T. These findings initiated follow-up studies on the capability of EPIA_S to extend the detection of T and T analogue misuse by carbon isotope ratio (CIR) mass spectrometry in sports drug testing.

Replacing PAPS: In vitro phase II sulfation of steroids with the liver S9 fraction employing ATP and sodium sulfate.

In vitro technologies provide the capacity to study drug metabolism where in vivo studies are precluded due to ethical or financial constraints. The metabolites generated by in vitro studies can assist anti-doping laboratories to develop protocols for the detection of novel substances that would otherwise evade routine screening efforts. In addition, professional bodies such as the Association of Official Racing Chemists (AORC) currently permit the use of in-vitro-derived reference materials for confirmation purposes providing additional impetus for the development of cost effective in vitro metabolism platforms.

Pseudomonas aeruginosa arylsulfatase: a purified enzyme for the mild hydrolysis of steroid sulfates.

The hydrolysis of sulfate ester conjugates is frequently required prior to analysis for a range of analytical techniques including gas chromatography-mass spectrometry (GC-MS). Sulfate hydrolysis may be achieved with commercial crude arylsulfatase enzyme preparations such as that derived from Helix pomatia but these contain additional enzyme activities such as glucuronidase, oxidase, and reductase that make them unsuitable for many analytical applications. Strong acid can also be used to hydrolyze sulfate esters but this can lead to analyte degradation or increased matrix interference.

In vitro directed evolution of enzymes expressed by E. coli in microtiter plates.

A method is described for using 96-well plates to prepare libraries of Escherichia coli cultures for screening a library of gene variants. This approach bypasses colony-picking to allow standard molecular biology laboratories to carry out directed evolution efficiently with a 96-well plate-reader and multichannel pipettes. Initial screens are applied to cultures that are rapidly prepared by diluting transformed cells so that an average of four cells starts each culture.

Pinpointing P450s associated with pyrethroid metabolism in the dengue vector, Aedes aegypti: developing new tools to combat insecticide resistance.

Background: Pyrethroids are increasingly used to block the transmission of diseases spread by Aedes aegypti such as dengue and yellow fever. However, insecticide resistance poses a serious threat, thus there is an urgent need to identify the genes and proteins associated with pyrethroid resistance in order to produce effective counter measures. In Ae.

Identification and validation of a gene causing cross-resistance between insecticide classes in Anopheles gambiae from Ghana.

In the last decade there have been marked reductions in malaria incidence in sub-Saharan Africa. Sustaining these reductions will rely upon insecticides to control the mosquito malaria vectors. We report that in the primary African malaria vector, Anopheles gambiae sensu stricto, a single enzyme, CYP6M2, confers resistance to two classes of insecticide.

Fermentative glycolysis with purified Escherichia coli enzymes for in vitro ATP production and evaluating an engineered enzyme.

Each of the twelve enzymes for glycolytic fermentation, eleven from Escherichia coli and one from Saccharomyces cerevisiae, have been over-expressed in E. coli and purified with His-tags. Simple assays have been developed for each enzyme and they have been assembled for fermentation of glucose to ethanol.

Cytochrome P450 6M2 from the malaria vector Anopheles gambiae metabolizes pyrethroids: Sequential metabolism of deltamethrin revealed.

Resistance to pyrethroid insecticides in the malaria vector Anopheles gambiae is a major threat to malaria control programmes. Cytochome P450-mediated detoxification is an important resistance mechanism. CYP6M2 is over-expressed in wild populations of permethrin resistant A.

Structural model and functional characterization of the Bemisia tabaci CYP6CM1vQ, a cytochrome P450 associated with high levels of imidacloprid resistance.

The neonicotinoid imidacloprid is one of the most important insecticides worldwide. It is used extensively against the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae), an insect pest of eminent importance globally, which was also the first pest to develop high levels of resistance against imidacloprid and other neonicotinoids in the field. Recent reports indicated that in both the B and Q biotypes of B.

Field-caught permethrin-resistant Anopheles gambiae overexpress CYP6P3, a P450 that metabolises pyrethroids.

Insects exposed to pesticides undergo strong natural selection and have developed various adaptive mechanisms to survive. Resistance to pyrethroid insecticides in the malaria vector Anopheles gambiae is receiving increasing attention because it threatens the sustainability of malaria vector control programs in sub-Saharan Africa. An understanding of the molecular mechanisms conferring pyrethroid resistance gives insight into the processes of evolution of adaptive traits and facilitates the development of simple monitoring tools and novel strategies to restore the efficacy of insecticides.

Directed evolution of yeast pyruvate decarboxylase 1 for attenuated regulation and increased stability.

Five generations of directed evolution resulted in yeast pyruvate decarboxylase 1 (Pdc1) variants with improved activity for 1 mM pyruvate at pH 7.5 in the presence of phosphate. The best variant, named 5LS30, contained the following mutations: A143T, T156A, Q367H, N396I, and K478R.

The Aedes aegypti glutathione transferase family.

In this report, we describe the glutathione transferase (GST) gene family in the dengue vector Aedes aegypti and suggest a novel role for a new class of mosquito GSTs. Twenty-six GST genes are present in Ae. aegypti, two of which are alternatively spliced to give a total of 29 transcripts for cytosolic GSTs.