tamyl hydrolase and folylpolyglutamate synthetase activities predict polyglutamylation of methotrexate in acute leukemias. Oncol. Res.

Defining the boundaries of substrate recognition within PKS domains is crucial to the rationally engineered biosynthesis of novel polyketide products, many of which could be prepared only with great difficulty, if at all, by direct chemical synthesis or semi-synthesis. Our results suggest that the KS2 domain of DEBS1 has a relatively relaxed specificity that can be exploited for the design and synthesis of medicinally important polyketide products.

A fourth fatty acid condensing enzyme was isolated from Eschenchia coli by its ability to restore elongating activity to a protein extract which had been treated with cerulenin, a condensing enzyme-specific inhibitor. The purified 3-ketoacyl-[acyl carrier protein] (ACP) synthase IV [3-oxoacyl-ACP synthase; acyl-ACP:malonyl-ACP C-acyltransferase (decarboxylating), EC 2.3

We have used 6-deoxyerythronolide B synthase (DEBS) as a model system to investigate molecular recognition by a modular polyketide synthase (PKS). DEBS consists of three proteins (DEBS1, -2, and -3) that biosynthesize the polyketide skeleton of the antibiotic erythromycin from propionyl-CoA and methylmalonyl-CoA. Active sites within these multifunctional proteins are organized into biosynthetic "modules", each of which catalyzes a discrete round of polyketide chain elongation and adjusts the appropriate level of beta-ketoacylthioester reduction. Using DEBS1, we demonstrate that there is a substantial degree of molecular recognition in the processing of the natural diketide chain elongation intermediate. Exogenously added (2S,3R)-2-methyl-3-hydroxypentanoic acid N-acetylcysteamine thioester is exclusively recognized by its cognate beta-ketoacyl-acyl carrier protein synthase domain in module 2 (KS2). Labeled diketide specifically acylated DEBS1 in crude protein extracts and limited proteolysis localized the binding to module 2. The precise site of acylation in DEBS1 was established by the finding that a Cys2200 Ala mutant of DEBS1, lacking the KS2 active-site cysteine, did not undergo acylation by the diketide. Pretreatment of the wild-type protein with the beta-ketoacyl-ACP synthase inhibitor cerulenin also blocked acylation. These results indicate that in addition to the purely organizational consequences resulting from the order of active-site domains, the programming of polyketide biosynthesis by modular PKSs involves a substantial level of molecular recognition. This conclusion has important implications for the use of PKSs to rationally design novel polyketides.

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The encapsulation of micro-organisms such as bacteria and fungi in biopolymers is currently being evaluated as delivery systems in many fields. Information about the viability and morphology of the organisms in the microparticle is often required to ascertain the longevity of the systems. A rapid method using fluorescent stains for microbial viability has been validated for organisms within alginate microparticles. Usually viability is assessed by dissolving the microparticles and cell culturing. This new method is advantageous for slow growing or filamentous organisms because these are not quickly or accurately enumerated by plate counts. In addition, the technique also allows the morphology of the organism to be monitored over time.

Graduate attributes, other than professional knowledge and skills, are now important outcomes for tertiary education. In science, anecdotal observations indicated minimal focus on: innovation; independent learning; communication; and societal involvement. Therefore, how graduate attributes were introduced, developed, taught and assessed into first and second year science units were investigated. Which graduate attributes were contextualized into learning objectives and activities together with how outcomes were measured and assessed were investigated. Results showed ~70% of teaching, development and assessment centred on disciplinary knowledge and most of the rest on professional skills. Oral presentations, portfolios, extended writing, and field trips comprised ~15% of assessment. Hence, a structured overview is needed to address the full scope of graduate attributes at the course level. There is an urgent need for the modern needs of tertiary education to be embraced by staff to ensure graduate attributes are attained commensurate with the expectations of the wider community.