Construction of cDNA libraries from trifluoroacetic acid-solvated amphibian skin secretions: molecular cloning of multiple bombinin-like peptide precursor transcripts from a library of yellow-bellied toad (Bombina variegata) secretion

Amphibian skin secretions are renowned as complex mixtures of bioactive peptides many of which are analogues of endogenous regulatory peptides. While skin secretions can be obtained non-invasively for peptidome analysis, parallel studies on the granular gland transcriptome required specimen sacrifice. The aim of the present study was to analyse archived skin secretions to determine the robustness of bioactive peptide precursor-encoding polyadenylated mRNAs in an attempt to extract maximum molecular information from rare samples. A range of solvated skin secretion samples were examined after lyophilisation for their potential to generate viable and comprehensive cDNA libraries based upon polyadenylated mRNA capture and amplification/cloning using appropriate commercial kits. Here we present unequivocal data that the granular gland transcriptome persists in a PCR amenable format even after storage for as long as 12 years in 0.1%(v/v) aqueous trifluoroacetic acid (TFA). We used a pooled skin secretion sample (2 ml) from the yellow-bellied toad, Bombina variegata (n = 14), containing the equivalent of 5 mg/ml of lyophilised skin secretion, that had been used in part for peptide isolation purposes in 1998 and had been stored at - 20 °C since that time. In the first cloning experiment, 12 different bombinin-like peptide precursor cDNAs were cloned encoding 17 different bombinins, the majority of which were novel. Subsequently, bombesin and bradykinin-related peptide precursor transcripts have been cloned successfully. These data illustrate the unexpected stability/longevity of the transcriptome in these secretions — a finding with implications for both this field of research and for the wider field of molecular biology.

Antecedents and Consequences of Social Identity Complexity: Intergroup Contact, Distinctiveness Threat, and Outgroup Attitudes

Social identity complexity defines people's more or less complex cognitive representations of the interrelationships among their multiple ingroup identities. Being high in complexity is contingent on situational, cognitive, or motivational factors, and has positive consequences for intergroup relations. Two survey studies conducted in Northern Ireland examined the extent to which intergroup contact and distinctiveness threat act as antecedents, and outgroup attitudes as consequences, of social identity complexity. In both studies, contact was positively, and distinctiveness threat negatively, associated with complex multiple ingroup perceptions, whereas respondents with more complex identity structures also reported more favorable outgroup attitudes. Social identity complexity also mediated the effects of contact and distinctiveness threat on attitudes. This research highlights that the extent to which individuals perceive their multiple ingroups in more or less complex and differentiated ways is of central importance to understanding intergroup phenomena.

Conceptions of Teacher Identity: Creating Self-Boxes as Arts-Based Self-Study

This paper presents a palimpsest of ways in which self-study draws upon arts-based methods not just as processes towards teacher development, but also as means to problematize and inquire into conceptualizations of the self. It focuses on the creation of individual self-boxes that mediate teachers’ dynamic narratives of identity. Concepts of the unitary self, the decentred self and the relationship between inner and outer experience are challenged and illustrated through two interlapping stories made manifest through the creation of self-boxes. From time immemorial man has known that he is the subject most deserving of his own study, but he has also fought shy of treating this subject as a whole, that is, in accordance with its total character. (Buber, 1947, p. 140)

Influence of the Time Scale on the Construction of Financial Networks

Background: In this paper we investigate the definition and formation of financial networks. Specifically, we study the influence of the time scale on their construction.

Rapid construction of arch bridges using the innovative FlexiArch

Masonry arches are strong, durable, aesthetically pleasing and largely maintenance free, yet since 1900 there has been a dramatic decline in their use. However, designers, contractors and clients now have access to a new method of constructing arches incorporating precast concrete voussoirs interconnected via polymeric reinforcement and a concrete screed. No centring is necessary, as the FlexiArch, when it is lifted, transforms under the forces of gravity into the desired arch shape. After discussing general aspects of innovation, the basic concept of the arch bridge system is presented along with technological advances since it was patented. Experiences gained from building over 40 FlexiArch bridges in the UK and Ireland and from model and full-scale tests carried out to validate the system during installation and in service are described. Thus under load the system behaves like a traditional masonry arch and existing analysis methods can be used for design and assessment.