ω-Transaminases for the amination of functionalised cyclic ketones.

The potential of a number of enantiocomplementary ω-transaminases (ω-TAms) in the amination of cyclic ketones has been investigated. After a preliminary screening of several compounds with increasing complexity, different approaches to shift the equilibrium of the reaction to the amine products were studied, and reaction conditions (temperature and pH) optimised. Interestingly, 2-propylamine as an amine donor was tolerated by all five selected ω-TAms, and therefore used in further experiments. Due to the higher conversions observed and interest in chiral amines studies then focused on the amination of α-tetralone and 2-methylcyclohexanone. Both ketones were aminated to give the corresponding amine with at least one of the employed enzymes. Moreover, the amination of 2-methylcyclohexanone was investigated in more detail due to the different stereoselectivities observed with TAms used. The highest yields and stereoselectivities were obtained using the ω-TAm from Chromobacterium violaceum (CV-TAm), producing 2-methylcyclohexylamine with complete stereoselectivity at the (1S)-amine position and up to 24 : 1 selectivity for the cis : trans [(1S,2R) : (1S,2S)] isomer.

Genetic variation of resistance to mercury poisoning in steelhead (Oncorhynchus mykiss) alevins.

Newly hatched steelhead alevins were obtained from the factorial breeding of 24 male and 10 female steelhead trout, Oncorhynchus mykiss. Each set of offspring were in a separate cell. They were tested for resistance to intoxication by methylmercuric chloride (CH3HgCl) in water at a nearly constant mercury concentration of 8 microg l(-1). High mortality (81% of the tested alevins) occurred within 2 weeks. Resistance to intoxication, as measured by the time to death, as well as by the survival rate, shared high paternal and maternal variation with negligible interaction. Heritability of time to death was 0.59 +/- 0.17; heritability of survival (all-or-none trait) was lower (0.26 +/- 0.09). Mercury in dead alevins increased with time to death, exhibiting a large environmental variation and (comparatively) negligible genetic influence. At the end of the bioassay, the mercury content in survivors varied widely (3-21 microg g(-1) wet weight). The content was greater than, but correlated with that of dead alevins from the same cells, and it showed little relation with survival rate. Thus, it seems that resistance to poisoning implies a tolerance to high levels of mercury rather than a limitation of its accumulation.

Physicians in training as quality managers: survival strategy for academic health centers.

Being responsible for medical education places academic health centers at a disadvantage in competing for managed care contracts. Although many suggestions have been made for changing medical education to produce physicians who are better prepared for the managed care environment, few studies have shown how physicians in training can actually contribute to the competitiveness of an academic health center. We present three examples of engaging trainees in projects with a population-based perspective that demonstrate how quality improvement for the academic health center can be operationalized and even led by physicians in training. In addition to gaining experience in a managed care skill that is increasingly important for future employment, physicians in training can simultaneously improve the quality of care delivered through the academic health center.

Fish biologics: vaccine standards for sport fisheries and commercial aquaculture.

Biologics for serodiagnostic identification of fish diesease agents and for determination of efficacy and potency of fish bacterins are now being offered on a limited basis to governmental hatchery biologists and commercial aquaculture farms by the National Fish Health Research Laboratory - Leetown. Difficulties arise when biologics are used for determining standard parameters for fish bacterins because there may be variations in the fishes' immune response due to population differences or effects of temperature and pollutants in the aquatic environment. The passive hemolytic plaque assay and passive hemagglutination tests are used to determine efficacy and potency of bacterins delivered by different routes and among batches of bacterins against fish disease agents of Aeromonas salmonicida (furunculosis) and Yersinia ruckeri (redmouth). The kinetics of the immune response with a defined population held in a standardized environment is established. We are presently recommending the development of a rainbow trout strain registry so consistency can be maintained for the standardization of biologics for fishes.