Relation between Indoor and Outdoor Exposure to Fine Particles Near a Busy Arterial Road

Various studies on indoor and outdoor particulate matter in the urban environment in the vicinity of busy arterial roads in the centre of the subtropical city of Brisbane have indicated that the revised United States Environmental Protection agency National Ambient air Quality Standards for Particulate matter PM2.5 could be exceeded not only outdoors but also indoors. The aim of this work was to investigate outdoor exposure to submicrometer particles and their relationship with indoor exposure in a hypothetical office building located in the vicinity of a busy arterial road. The outdoor exposure values and trends were measured in terms of particle number in the submicrometer size range and were then recalculated to represent mass concentration trends. The results of this study indicate that exposure to PM0.7 particles in ambient air close to a busy road often exceeds the levels of the annual and 24-hour US EPA NAAQS PM2.5 standards. It is likely that exposure to PM2.5 is even higher, and may significantly exceed these standards

Cathepsin C from Schistosoma japonicum cDNA encoding the preproenzyme and its phylogenetic relationships

A cDNA encoding preprocathepsin C was isolated from adults of the asian blood fluke Schistosoma japonicum. The deduced amino acid sequence of S. japonicum cathepsin C comprised 458 amino acid residues; 22 NH-terminal residues corresponding to the signal peptide, 199 residues corresponding to the propeptide and 237 COOH-terminal residues corresponding to the mature enzyme region. The amino acid sequence of this preprocathepsin showed 43 % and 50% identity to that of human and rat, respectively. The preproenzyme shared only 59% identity with the sequence for a cathepsin C reported from Schistosoma mansoni, differing from it in active-site residues and in its potential N-glycosylation sites. Northern-blot analysis showed that S. japonicum cathepsin C was expressed in greater quantities in female than in male parasites. Phylogenetic analysis utilizing the mature enzyme sequences of S. japonicum and other cathepsin Cs demonstrated that cathepsin Cs and cathepsin Bs shared a common ancestry. The unusually long prosegment observed in cathepsin C from S. japonicum and from other species was compared to that of cathepsin Bs and cathepsin Ls. The extension contained two blocks of residues which were highly conserved among cathepsin Cs. The COOH terminus of the prosegment exhibited a composite of features present in the prosegments of cathepsin Ls and cathepsin Bs. Most significantly, given the common ancestry of cathepsin B and cathepsin C, the prosegment of cathepsin C included ERFNIN-like motifs and other residues more characteristic of non-cathepsin-B-like members of the papain superfamily such as cathepsin L

Leucine aminopeptidase of the human blood flukes, Schistosoma mansoni and Schistosoma japonicum

An array of schistosome endoproteases involved in the digestion of host hemoglobin to absorbable peptides has been described, but the exoprotease responsible for catabolising these peptides to amino acids has yet to be identified. By searching the public databases we found that Schistosoma mansoni and Schistosoma japonicum express a gene encoding a member of the M17 family of leucine aminopeptidases (LAPs). A functional recombinant S. mansoni LAP produced in insect cells shared biochemical properties, including pH optimum for activity, substrate specificity and reliance on metal cations for activity, with the major aminopeptidase activity in soluble extracts of adult worms. The pH range in which the enzyme functions and the lack of a signal peptide indicate that the enzyme functions intracellularly. Immunolocalisation studies showed that the S. mansoni LAP is synthesised in the gastrodermal cells surrounding the gut lumen. Accordingly, we propose that peptides generated in the lumen of the schistosome gut are absorbed into the gastrodermal cells and are cleaved by LAP to free amino acids before being distributed to the internal tissues of the parasite. Since LAP was also localised to the surface tegument it may play an additional role in surface membrane re-modelling