A transcriptomic analysis of Echinococcus granulosus larval stages:implications for parasite biology and host adaptation

The cestode Echinococcus granulosus--the agent of cystic echinococcosis, a zoonosis affecting humans and domestic animals worldwide--is an excellent model for the study of host-parasite cross-talk that interfaces with two mammalian hosts. To develop the molecular analysis of these interactions, we carried out an EST survey of E. granulosus larval stages. We report the salient features of this study with a focus on genes reflecting physiological adaptations of different parasite stages.We generated ~10,000 ESTs from two sets of full-length enriched libraries (derived from oligo-capped and trans-spliced cDNAs) prepared with three parasite materials: hydatid cyst wall, larval worms (protoscoleces), and pepsin/H(+)-activated protoscoleces. The ESTs were clustered into 2700 distinct gene products. In the context of the biology of E. granulosus, our analyses reveal: (i) a diverse group of abundant long non-protein coding transcripts showing homology to a middle repetitive element (EgBRep) that could either be active molecular species or represent precursors of small RNAs (like piRNAs); (ii) an up-regulation of fermentative pathways in the tissue of the cyst wall; (iii) highly expressed thiol- and selenol-dependent antioxidant enzyme targets of thioredoxin glutathione reductase, the functional hub of redox metabolism in parasitic flatworms; (iv) candidate apomucins for the external layer of the tissue-dwelling hydatid cyst, a mucin-rich structure that is critical for survival in the intermediate host; (v) a set of tetraspanins, a protein family that appears to have expanded in the cestode lineage; and (vi) a set of platyhelminth-specific gene products that may offer targets for novel pan-platyhelminth drug development.This survey has greatly increased the quality and the quantity of the molecular information on E. granulosus and constitutes a valuable resource for gene prediction on the parasite genome and for further genomic and proteomic analyses focused on cestodes and platyhelminths

Institutional Labor Economics, the New Personnel Economics, and Internal Labor Markets: A Reconsideration

The author illustrates the utility of institutional labor economics and makes a case for a reconsideration of it. Two recent developments motivate this effort: the rise of New Personnel Economics (NPE) as a significant subfield of labor economics and the substantial shifts in work organization that have taken place since the 1990s. Understanding how and why firms have reorganized work opens the door for a renewed interest in institutional approaches. The author explains that the rules of institutional labor markets (ILMs) emerge from the competition between organizational interest groups—unions, personnel professionals, and the government—and competing views of firms’ objectives—resulting in the rise of ILMs, the slow diffusion of High Performance Work Systems, strategies used to obtain a high level of commitment from workers, the use of contingent employees, and the spread of new promotion rules in response to equal employment opportunity pressures. As such, the role of power and influence in establishing work rules is of central concern, though more conventional NPE considerations also remain important