Work-related stress is an important issue in any industry, particularly for construction workers where stressful environments are frequently encountered. Critical questions are therefore: what are the primary stressors in the construction workplace ; and what are the relationships between the strain effect of psychological distress and the countermeasures and coping mechanisms used by construction workers? The first question was addressed using Qmethodology survey with 18 participants. The results show that time and personal finance, and the task nature of the work, are important stressors. For the second question, a questionnaire survey administered to 91 participants on two construction sites of a single contractor was used to collect data about the stressors, psychological strain effects and coping strategies they used. Mediated regression analysis of the data showed that lack of personal and family time, increases in the cost of living, and fears about job security all act as powerful stressors. Coping strategies including acceptance, self-blame, and disengagement are associated with higher levels of psychological distress. Increased substance use, while associated with lower levels of anxiety, may only be a short term coping mechanism. An anomaly was found with humour as a coping strategy, where the relationship was found to be counter-intuitive and contrary to the findings of previous research. Future research should examine this more closely. Employers should better inform workers about the negative effects of maladaptive coping strategies, and offer opportunities for adopting more positive alternatives.

The first bacterial N-linked glycosylation system was discovered in Campylobacter jejuni, and the key enzyme involved in the coupling of glycan to asparagine residues within the acceptor sequon of the glycoprotein is the oligosaccharyltransferase PglB. Emerging genome sequence data have revealed that pglB orthologues are present in a subset of species from the Deltaproteobacteria and Epsilonproteobacteria, including three Helicobacter species: H. pullorum, H. canadensis, and H. winghamensis. In contrast to C. jejuni, in which a single pglB gene is located within a larger gene cluster encoding the enzymes required for the biosynthesis of the N-linked glycan, these Helicobacter species contain two unrelated pglB genes (pglB1 and pglB2), neither of which is located within a larger locus involved in protein glycosylation. In complementation experiments, the H. pullorum PglB1 protein, but not PglB2, was able to transfer C. jejuni N-linked glycan onto an acceptor protein in Escherichia coli. Analysis of the characterized C. jejuni N-glycosylation system with an in vitro oligosaccharyltransferase assay followed by matrix-assisted laser desorption ionization (MALDI) mass spectrometry demonstrated the utility of this approach, and when applied to H. pullorum, PglB1-dependent N glycosylation with a linear pentasaccharide was observed. This reaction required an acidic residue at the ؊2 position of the N-glycosylation sequon, as for C. jejuni. Attempted insertional knockout mutagenesis of the H. pullorum pglB2 gene was unsuccessful, suggesting that it is essential. These first data on N-linked glycosylation in a second bacterial species demonstrate the similarities to, and fundamental differences from, the well-studied C. jejuni system.

cThe Gram-negative bacterium Campylobacter jejuni encodes an extensively characterized N-linked protein glycosylation system that modifies many surface proteins with a heptasaccharide glycan. In C. jejuni, the genes that encode the enzymes required for glycan biosynthesis and transfer to protein are located at a single pgl gene locus. Similar loci are also present in the genome sequences of all other Campylobacter species, although variations in gene content and organization are evident. In this study, we have demonstrated that only Campylobacter species closely related to C. jejuni produce glycoproteins that interact with both a C. jejuni N-linked-glycan-specific antiserum and a lectin known to bind to the C. jejuni N-linked glycan. In order to further investigate the structure of Campylobacter N-linked glycans, we employed an in vitro peptide glycosylation assay combined with mass spectrometry to demonstrate that Campylobacter species produce a range of structurally distinct N-linked glycans with variations in the number of sugar residues (penta-, hexa-, and heptasaccharides), the presence of branching sugars, and monosaccharide content. These data considerably expand our knowledge of bacterial N-linked glycan structure and provide a framework for investigating the role of glycosyltransferases and sugar biosynthesis enzymes in glycoprotein biosynthesis with practical implications for synthetic biology and glycoengineering.