A glycosyl hydrolase family 16 gene is responsible for the endogenous production of β-1,3-glucanases within decapod crustaceans

To identify the gene responsible for the production of a β-1,3-glucanase (laminarinase) within crustacea, a glycosyl hydrolase family 16 (GHF16) gene was sequenced from the midgut glands of the gecarcinid land crab, Gecarcoidea natalis and the freshwater crayfish, Cherax destructor. An open reading frame of 1098bp for G. natalis and 1095bp for C. destructor was sequenced from cDNA. For G. natalis and C. destructor respectively, this encoded putative proteins of 365 and 364 amino acids with molecular masses of 41.4 and 41.5kDa. mRNA for an identical GHF16 protein was also expressed in the haemolymph of C. destructor. These putative proteins contained binding and catalytic domains that are characteristic of a β-1,3-glucanase from glycosyl hydrolase family 16. The amino acid sequences of two short 8-9 amino acid residue peptides from a previously purified β-1,3-glucanase from G. natalis matched exactly that of the putative protein sequence. This plus the molecular masses of the putative proteins matching that of the purified proteins strongly suggests that the sequences obtained encode for a catalytically active β-1,3-glucanase. A glycosyl hydrolase family 16 cDNA was also partially sequenced from the midgut glands of other amphibious (Mictyrisplatycheles and Paragrapsus laevis) and terrestrial decapod species (Coenobita rugosus, Coenobita perlatus, Coenobita brevimanus and Birgus latro) to confirm that the gene is widely expressed within this group. There are three possible hypothesised functions and thus evolutionary routes for the β-1,3-glucanase: 1) a digestive enzyme which hydrolyses β-1,3-glucans, 2) an enzyme which cleaves β-1,3-glycosidic bonds within cell walls to release cell contents or 3) an immune protein which can hydrolyse the cell walls of potentially pathogenic micro-organisms.

Drivers of teaching effectiveness: Views from accounting educator exemplars in Australia

This paper summarizes the views, obtained via a survey instrument created by the authors and reported in studies by Stout and Wygal, of 22 accounting educator teaching exemplars from Australia. Each of these individuals has been cited for teaching excellence through receipt of one or more formal teaching awards. The paper responds to calls in Australia for increased attention to the dimensions of teaching effectiveness and to initiatives in the United States calling for a broader sharing of information among members of the academy regarding the characteristics of teaching effectiveness. Little direct evidence from the field of accounting education is available to date regarding such characteristics or antecedents of teaching effectiveness in the student learning environment. Our research therefore extends in a fundamental way the work of Stice and Stocks and Stout and Wygal. Specifically, perceptions from a sample of award-winning non-US faculties regarding the 'drivers of teaching effectiveness' in accounting education are recorded and analyzed. In decreasing order of perceived importance, drivers of teaching effectiveness are: having a student focus; commitment to teaching (as a profession); high levels of preparation/organization; the ability to link subject matter to the practice environment; and, instructor skills and attributes. This paper adds to our understanding of the drivers of teaching effectiveness and begins the process of creating a worldwide knowledge base in accounting education. The paper should be of interest to accounting faculty members interested in improving their teaching effectiveness and/or mentoring junior faculty members. © 2014 © 2014 Taylor & Francis.