During the past four years Alan Amory, a lecturer in Biology, has investigated the use of multimedia as a teaching resource and converted his courses from old-style lectures and practicals to constructivist-like classrooms. He also enjoys the thrill of creating software. Kevin Naicker, an Honours student at the time of this research, is interested in the use of computer technologies, especially the World Wide Web, in education. Jacky Vincent, our graphic artist, with her abounding enthusiasm and experience, enjoys designing unique virtual worlds and developing game scenarios. Claudia Adams, a zoologist and librarian, helped in the finding and organisation of the content and enjoys the creative side of plot development. AbstractPlaying games is an important part of our social and mental development. This research was initiated to identify the game type most suitable to our teaching environment and to identify game elements that students found interesting or useful within the different game types. A group of twenty students played four commercial games (SimIsle, Red Alert, Zork Nemesis and Duke Nukem 3D). Results suggest that students prefer 3D-adventure (Zork Nemesis) and strategy (Red Alert) games to the other types ("shoot-em-up", simulation) with Zork Nemesis ranked as the best. Students rated game elements such as logic, memory, visualisation and problem solving as the most important game elements. Such elements are integral to adventure games and are also required during the learning process. We present a model that links pedagogical issues with game elements. The game space contains a number of components, each encapsulates specific abstract or concrete interfaces. Understanding the relationship between educational needs and game elements will allow us to develop educational games that include visualisation and problem solving skills. Such tools could provide sufficient stimulation to engage learners in knowledge discovery, while at the same time developing new skills.

Complex computer and video games may provide a vehicle, based on appropriate theoretical concepts, to transform the educational landscape. Building on the original game object model (GOM) a new more detailed model is developed to support concepts that educational computer games should: be relevant, explorative, emotive, engaging, and include complex challenges; support authentic learning activities that are designed as narrative social spaces where learners are transformed through exploration of multiple representation, and reflection; be gender-inclusive, include non-confrontational outcomes, and provide appropriate role models; develop democracy, and social capital through dialogue that is supported by means of computer mediated-communication tools; and include challenges, puzzles or quests, which form the core of the learning process, where access to explicit knowledge, conversations, and reflection results in the construction of tacit knowledge. It is argued that the GOM version II can be used not only to support the development of educational computer games but to provide a mechanism to evaluate the use of computer games in the classroom.

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The sacQ gene from Bacillus An interesting property of Bacillus subtilis is its ability to secrete a great number of enzymes (21), including some industrially useful ones like ax-amylase, proteases, or glticanases. However, the amount of proteins secreted by B. subtilis has been found to be a serious limitation compared to Bacillus strains used in industry, like B. licheniformis, B. amyloliquefaciens, or B. stearothermophilus, which are capable of producing much larger amounts of secreted enzymes.A number of mutations of B. subtilis 168 have been isolated that increase the production of secreted enzymes. sdcU-hyperproducing [sacU(Hy)] mutants (12), which are identical to pap (3, 37) and amyB (25) mutants, were characterized by a pleiotropic phenotype including hyperproduction of levansucrase, protease, and ax-amylase, absence of flagella, and low transformation levels. A similar phenotype was given by the sacQ(Hy) mutation, which was mapped at a different locus (13,14).In this report, we describe the identification of a plasmid containing a DNA fragment from B. licheniformis that confers to the recipient B. subtilis strain a hypersecretion phenotype similar to the one given by the sacQ(Hy) or sacU(Hy) mutation. From subcloning experiments, we obtained evidence that a 46-residue polypeptide is involved in the expression of the phenotype. A series of deletions was camed out in the cloned fragment, and the phenotype was lost when the deletions affected the polypeptide coding sequence. Moreover, hypersecretion was given by a 228-base-pair (bp) Moreover, we clearly show in this report that the sacQ gene isolated from a B. licheniformis high protease producer appears to encode a sacQ protein which is more efficient than the B. subtilis sacQ polypeptide in conferring the hypersecretion phenotype. The natural promoter of the sacQ gene was indeed replaced by an inducible promoter (spac), and the hypersecretion of protease and levansucrase was specifically obtained under conditions of full induction of the promoter. This is strong evidence that the increased expression of both enzymes is due to an increase of sacQ protein synthesis.Nothing, however, is known about the mechanism by which the increased expression of the target genes is produced by sacQ. The six different target genes identified in this study seem to be submitted to different growth phase regulation. For example, levansucrase is only synthesized during exponential growth, whereas alkaline protease is produced during the stationary phase.An attractive hypothesis is to suggest that sacQ regulates the synthesis of an essential component of the secretion machinery, since all of the target genes identified in this report encode a secreted enzyme. However, our results suggest that this hypothesis is unlikely. This is shown from a detailed study of one target of sacQ regulation, the levansucrase gene. We show that the target site is included in a 440-bp fragment located upstream from the coding sequence and ribosome-binding site of levansucrase, which sugges...

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