First comprehensive multi-tissue transcriptome of Cherax quadricarinatus (Decapoda: Parastacidae) reveals unexpected diversity of endogenous cellulase

The Australian freshwater crayfish species, Cherax quadricarinatus Von Martens, 1868, is an important commercial and invasive species that is also being increasingly used as a model organism to address important and interesting questions in crustacean biology. Through deep sequencing of the transcriptome of C. quadricarinatus from the hepatopancreas and four other tissues, we examine the evolution of endogenously transcribed cellulase genes and provide new insights into controversial issues regarding the nutritional biology of crayfishes. A cluster assembly approach yielded one of the highest quality transcriptome assemblies for a decapod crustacean to date. A total of 206,341,872 reads with an average read length of 80 bp were generated from sequencing the transcriptomes from the heart, kidney, hepatopancreas, nerve, and testis tissues. The assembled transcriptome contains a total of 44,525 transcripts. A total of 65 transcripts coding for carbohydrate-active enzymes (CAZy) were identified based on hidden Markov model (HMM), and a majority of them display high relative transcript abundance in the hepatopancreas tissue, supporting their role in nutrient digestion. Comprehensive phylogenetic analyses of proteins belonging to two main glycosyl hydrolase families (GH9 and GH5) suggest shared ancestry of C. quadricarinatus cellulases with other characterized crustacean cellulases. Our study significantly expands the number of known crustacean-derived CAZy-coding transcripts. More importantly, the surprising level of evolutionary diversification of these proteins in C. quadricarinatus suggests that these enzymes may have been of critical importance in the adaptation of freshwater crayfishes to new plant-based food sources as part of their successful invasion of freshwater systems from marine ancestors.

Ecological niche modelling and DNA sequencing support a new, morphologically cryptic beetle species unveiled by DNA barcoding

Background: DNA sequencing techniques used to estimate biodiversity, such as DNA barcoding, may reveal cryptic species. However, disagreements between barcoding and morphological data have already led to controversy. Species delimitation should therefore not be based on mtDNA alone. Here, we explore the use of nDNA and bioclimatic modelling in a new species of aquatic beetle revealed by mtDNA sequence data.

Methodology/Principal Findings: The aquatic beetle fauna of Australia is characterised by high degrees of endemism, including local radiations such as the genus Antiporus. Antiporus femoralis was previously considered to exist in two disjunct, but morphologically indistinguishable populations in south-western and south-eastern Australia. We constructed a phylogeny of Antiporus and detected a deep split between these populations. Diagnostic characters from the highly variable nuclear protein encoding arginine kinase gene confirmed the presence of two isolated populations. We then used ecological niche modelling to examine the climatic niche characteristics of the two populations. All results support the status of the two populations as distinct species. We describe the south-western species as Antiporus occidentalis sp.n.

Conclusion/Significance: In addition to nDNA sequence data and extended use of mitochondrial sequences, ecological niche modelling has great potential for delineating morphologically cryptic species. © 2011 Hawlitschek et al.

It makes you realize, really, just how deep your subtext is : Literature, subjectivity and curriculum change

This paper draws on the notion of discourse to explore complex relationships between teachers and curriculum change. It uses poststructuralist views of discourse to explore ways in which school subjects, such as Literature, are discursively constructed across time, while teachers too are positioned within discourses that shape the ways they understand the subject and themselves as teachers of it. This paper reports on the experience of a small group of teachers of a new literature course in the Australian state of Victoria. Nine teachers were interviewed over 3 years, and the interview transcripts read for traces of discourses formative in shaping their response to the new course. I identified three discourses: Leavisite and New Critical formations of the subject Literature; charismatic pedagogy; and critical theory, which was embodied in the new subject's study design. These 3 discourses, together with the traditions and culture of the school, form the framework for analysis of the interviews. The paper explores ways in which the teachers' positioning within this mix of discourses and settings variously supported or undermined their preparedness to accept new configurations of the subject Literature as well as the implications of curriculum change not just for constructions of the subject but also for teacher subjectivity.

Genome sequencing: a grin without a cat

In some types of unicellular algae, the chloroplasts have their own nucleus — a legacy of the time when the chloroplast was a free-living cell. The sequence of the genome in one such nucleus is now revealed.

Eulerian superpath approach to correct sequencing error in shotgun assembly

This work describes an error correction method based on the Euler Superpath problem. Sequence data is mapped to an Euler Superpath dynamically by Merging Transformation. With restriction and guiding rules, data consistency is maintained and error paths are separated from correct data: Error edges are mapped to the correct ones and after substitution (of error edges with right paths), corresponding errors in the sequencing data are eliminated.

Modeling a just-in-time plant using sequencing algorithms

An Australian automotive component company plans to assemble and deliver seats to customer on just-in-time basis. The company management has decided to model operations of the seat plant to help them make decisions on capital investment and labour requirements. There are four different areas in seat assembly and delivery areas. Each area is modeled independently to optimise its operations. All four areas are then combined into one model called the plant model to model operations of seat plant from assembly to delivery. Discrete event simulation software is used to model the assembly operations of seat plant.

Fostering deep and elaborative learning and generic(soft) skill development: the strategic use of case studies in accounting education

It is vital that accounting educators take responsibility for the development of students' generic (soft) skills in conjunction with, discipline-specific skills. Research indicates that the typical learning styles of accounting students are not suited to the acquisition of generic skills. In this paper learning theory is used to provide a framework to support the use of case studies as a tool to promote appropriate learning styles and thereby enhance generic skill development. The paper details a number of strategies that may be implemented with case studies to achieve these goals. The implications for accounting educators, which are significant, are discussed.

An ecologically mixed brachiopod fauna from Changhsingian deep-water basin of South China: consequence of end-Permian global warming

The Late Permian Shaiwa Group of the Ziyun area of Guizhou, South China is a deep-water facies succession characterized by deep-water assemblages of pelagic radiolarians, foraminifers, bivalves, ammonoids and brachiopods. Here we report 20 brachiopod species in 18 genera from the uppermost Shaiwa Group. This brachiopod fauna is latest Changhsingian in age and dominated by productides. The palaeoecologic and taphonomic analysis reveals that the brachiopod fauna is preserved in situ. The attachment modes and substratum preference demonstrate that the Shaiwa brachiopod fauna comprises admixed elements of deep-water and shallow-water assemblages. The presence of the shallow-water brachiopods in the Shaiwa faunas indicates the involuntary settlement of shallow-water brachiopods. The stressed ecologic pressure, triggered by warming surface waters, restricted ecospace and short food sources, may have forced some shallow-water elements to move to hospitable deep-water settings and others to modify their habiting behaviours and exploit new ecospace in deep-water environments. We infer that the end-Permian global warming and subsequent transgression event may have accounted for the stressed environmental pressure in the shallow-water communities prior to the end-Permian mass extinction.

Fat content of chips, quality of frying fat and deep-frying practices in New Zealand fast food outlets

Objectives: To collect baseline data on the fat content of hot chips, quality (degradation) of cooking fat, deep-frying practices and related attitudes in fast food outlets in New Zealand. To identify the key determinants of the fat content of chips and quality of cooking fat. Methods: A nationally representative sample of fast food outlets (n=150, response rate 80%) was surveyed between September 1998 and March 1999. Data collected included a questionnaire, observation of cooking practices and analysis of cooked chips and frying fat. Results: Only 8% of independent operators had formal training in deep frying practices compared with 93% of chain operators. There was a wide range of fat content of chips (5%-20%, mean 11.5%). The use of thinner chips, crinkle cut chips and lower fryer fat temperature were associated with higher chip fat content. Eighty-nine per cent of chain outlets used 6–10 mm chips compared with 83% of independent outlets that used chips ≥12 mm. A wide range of frying temperatures was recorded (136–233°C) with 58% of outlets frying outside the reference range (175–190°C). As indices of fat degradation, fat acid and polar compound values above the recommended levels occurred in 54% and 5% of outlets respectively. Operators seemed willing to learn more about best practice techniques, with lack of knowledge being the main barrier to change. Conclusions and implications: Deep frying practices could be improved through operator training and certification options. Even a small decrease in the mean fat content of chips would reduce the obesogenic impact of this popular food.