Peter B. Baker

Illicitly imported heroin products: some physical and chemical features indicative of their origin.

Samples taken from over 200 seizures of imported illicit heroin preparations of known geographical origin have been examined by gas liquid chromatography (GLC). The chromatographic characteristics were considered in conjunction with the physical appearance of the materials and it was found possible in many instances to discriminate between samples of different origin. Thus by carrying out GLC and HPLC and a visual inspection on a sample of unknown provenance, it may be possible to give an opinion as to its geographical origin.

The Analysis of Lysergide (LSD): The Development of Novel Enzyme Immunoassay and Immunoaffinity Extraction Procedures Together with an HPLC-MS Confirmation Procedure

A forensic procedure for the screening and confirmation of the presence of lysergide (lysergic acid diethylamide, LSD) in urine is described together with the evaluation of a novel enzyme immunoassay (EIA) and immunoaffinity extraction procedure. Following initial screening using either an established radioimmunoassay (RIA) or a novel EIA procedure, a quantitative estimate is established using a conventional high performance liquid chromatography-fluorescence (HPLC) technique following solid phase extraction. Final confirmation and quantitation, without derivatization, is established using HPLC in combination with electrospray ionization (ESI) mass spectrometry using methysergide as an internal standard. The detection limit of LSD in urine is 0.5 ng/mL. A blind trial confirmed the validity of the results. The choice of internal standard is discussed. Consideration is given to the photosensitivity of LSD solutions. A study of potential interferants in the HPLC-MS confirmation of LSD is presented and shows that for the wide range of compounds studied, there are none that would interfere with this confirmation technique. A comparison is shown between solid phase and immunoaffinity extraction/clean up procedures, and between RIA and EIA screening procedures.

Microbial oxidation of alpha-pinene by Serratia marcescens

SummaryA strain of the bacterium Serratia marcescens, isolated from sewage sludge, can oxidise the terpene hydrocarbon α-pinene to produce rans-verbenol as the major product, with verbeone and trans-sobrerol as minor products. A change in nitrogen source and inclusion of glucose as a second carbon source caused the bacterium to produce α-terpineol as the major oxidation product. Products were identified by gas liquid chromatography and mass spectrometry.

Biotransformations of fluoroaromatic compounds

Abstract Fluorochemicals are rare in Nature and fluoroaromatic compounds have not been described as natural products with respect to de novo formation of aryl-fluorine bonds. By contrast many synthetic fluoroaromatic compounds are substrates for several microbial enzymes, particularly oxygenases, and are transformed to previously undescribed fluorochemicals suitable for further modifications by other enzymes systems or by chemical means. These lead to interesting multi-functional molecules, monomers for novel chiral and achiral polymers, chiral intermediates and synthons for some heterocycles and α- amino acids. Wild-type and mutant microbial strains have been used to biotransform some fluoroaromatic compounds in near quantitative yields to novel fluorinated products, as well as other flourophenolics already known by chemical synthesis. Some of the microbial transformations of mono-, di-, tri- and tetrafluoroaromatic compounds are described, and the vast potential of further biotransformations is indicated.

The rapid determination of cocaine and other local anesthetics using field tests and chromatography.

The application of field tests and chromatography to the detection of cocaine and some other local anesthetics that have been used to adulterate cocaine is described. Initial screening of samples by field tests, followed by concurrent TLC and GC, enables rapid identification of these compounds to be achieved. In particular, the use of flow-programmed GC shortens the time for analysis compared with conventional GC and requires negligible equilibration time between consecutive runs [12]. The method gives reliable quantitative data.

Dehalogenation of haloalkanes byRhodococcus erythropolis Y2

Phodococcus erythropolis Y2 produced two types of dehalogenase: a hydrolytic enzyme, that is an halidohydrolase, which was induced by C3 to C6 1-haloalkane substrates, and at least one oxygenase-type dehalogenase induced by C7 to C16 1-haloalkanes andn-alkanes. The oxygenase-type activity dehalogenated C4 to C18 1-chloroalkanes with an optimum activity towards 1-chlorotetradecane. The halidohydrolase catalysed the dehalogenation of a wide range of 1- and α,ω-disubstituted haloalkanes and α,ω-substituted haloalcohols. In resting cell suspensions of hexadecane-grownR. erythropolis Y2 the oxygenase-type dehalogenase had a specific activity of 12.9 mU (mg protein)−1 towards 1-chlorotetradecane (3.67 mU mg−1 towards 1-chlorobutane) whereas the halidohydrolase in 1-chlorobutane-grown batch cultures had a specific activity of 44 mU (mg protein)−1 towards 1-chlorobutane.The significance of the two dehalogenase systems in a single bacterial strain is discussed in terms of their contribution to the overall catabolic potential of the organism.Rhodococcus erythropolis Y2 produced two types of dehalogenase: a hydrolytic enzyme, that is an halidohydrolase, which was induced by C3 to C6 1-haloalkane substrates, and at least one oxygenase-type dehalogenase induced by C7 to C16 1-haloalkanes and n-alkanes. The oxygenase-type activity dehalogenated C4 to C18 1-chloroalkanes with an optimum activity towards 1-chlorotetradecane. The halidohydrolase catalysed the dehalogenation of a wide range of 1- and alpha,omega-disubstituted haloalkanes and alpha,omega-substituted haloalcohols. In resting cell suspensions of hexadecane-grown R. erythropolis Y2 the oxygenase-type dehalogenase had a specific activity of 12.9 mU (mg protein)-1 towards 1-chlorotetradecane (3.67 mU mg-1 towards 1-chlorobutane) whereas the halidohydrolase in 1-chlorobutane-grown batch cultures had a specific activity of 44 mU (mg protein)-1 towards 1-chlorobutane. The significance of the two dehalogenase systems in a single bacterial strain is discussed in terms of their contribution to the overall catabolic potential of the organism.

Biotransformations Of Fluoroaromatic Compounds: Accumulation Of Hydroxylated Products From 3-Fluorophthalic Acid Using Mutant Strains Of Pseudomonas Testosteroni

Biotransformations of 3-fluorophthalic acid have been investigated using blocked mutants of Pseudomonas testosteroni that are defective in the metabolism of phthalic acid (benzene-1,2-dicar-boxyfic acid). Mutant strains were grown with L-glutamic acid in the presence of 3-fluorophthalic acid as inducer of phthalic acid catabolic enzymes. Products that accumulated in the medium were isolated, purified and identified as the fluoroanalogues of those produced from phthalic acid by the same strains. The previously undescribed fluorochemicals cis-3-fluoro-4,5-dihydro-4,5-dihydroxyphthalic acid (VI) and 3-fluoro-4,5-dihydroxyphthalic acid (VII) have been obtained by biotransformation of 3-fluorophthalic acid, and 3-fluoro-5-hydroxyphthalic acid (X) from (VI) by freeze drying. In addition, samples of 2-fluoro-3,4-dihydroxybenzoic acid (2-fluoroprotocatechuic acid, VIII) and 3-fluoro-4,Sdi-hydroxybenzoic acid (5-fluoroprotocatechuic acid, IX) were obtained with a mutant deficient in the ring-fission enzyme, showin...

Microbial transformation of squalene: Formation of a novel ketone from squalene by a Rhodococcus sp.

SummaryA Rhodococcus sp., isolated from soil, was able to use squalene as the sole carbon source. The principal metabolic product from squalene was detected by thin layer and high performance liquid chromatography, and identified as 2, 6, 10, 15, 19, 23-hexamethyltetraco-sa-2, 6, 10, 14, 18, 22-hexaen-12-one by nuclear magnetic resonance, infrared, ultra-violet, and mass spectrometry.

Methane Monooxygenase Biotransformations: Highly Stereoselective Hydroxylation of 3-Methylcyclohexene by Methane Monooxygenase: Steric and Electronic Effects on Product Distribution

Cell extracts containing soluble methane monooxygenase from Methylococcus capsulatus, Methylosinus sporium and Methylosinus trichosporium converted 3-methylcyclohexene to predominantly cis-4-methylcyclohex-2-enol, contrary to an earlier suggestion of rearrangement products. In the case of M. capsulatus extracts, this comprised 90% of the total products. The product mixture was consistent with predictions based on chemical reactivity of the substrate, steric effects in the substrate and products and enzymic constraints operating in concert.

Workshop 3 Environmental Impact

The workshop on environmental impact was well attended, with approximately 70 participants. The session opened with a presentation by Dr. Lynch, who discussed exchange processes. He stated his lack of conviction that a principal ecological issue is at stake. That introduction of genetically-modified microorganisms into the environment is damaging environmentally has not been definitively demonstrated. An impetus for new methodologies in microbial ecology is plant genetic modification. In trying to determine the impact of genetically-modified plants on microbial communities, the British Department of the Environment sought to determine critical baseline factors. However, the dominant bacterial members of a community are not clearly understood. The Oxford Experimental Virology Group has carried out releases, e.g. studies of leaf and root surfaces in soil have been done to determine the dominant microbial members. The dominant versus genetically-modified microorganisms are appropriately marked and have been studied to determine any impact. Bacteria do not dominate soil; it is mainly the fungal community. Thus, it is necessary to determine the baseline fungal community.