A Novel Metagenomic Short-Chain Dehydrogenase/Reductase Attenuates Pseudomonas aeruginosa Biofilm Formation and Virulence on Caenorhabditis elegans

In Pseudomonas aeruginosa, the expression of a number of virulence factors, as well as biofilm formation, are controlled by quorum sensing (QS). N-Acylhomoserine lactones (AHLs) are an important class of signaling molecules involved in bacterial QS and in many pathogenic bacteria infection and host colonization are AHL-dependent. The AHL signaling molecules are subject to inactivation mainly by hydrolases (Enzyme Commission class number EC 3) (i.e. N-acyl-homoserine lactonases and N-acyl-homoserine-lactone acylases). Only little is known on quorum quenching mechanisms of oxidoreductases (EC 1). Here we report on the identification and structural characterization of the first NADP-dependent short-chain dehydrogenase/reductase (SDR) involved in inactivation of N-(3-oxo-dodecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) and derived from a metagenome library. The corresponding gene was isolated from a soil metagenome and designated bpiB09. Heterologous expression and crystallographic studies established BpiB09 as an NADP-dependent reductase. Although AHLs are probably not the native substrate of this metagenome-derived enzyme, its expression in P. aeruginosa PAO1 resulted in significantly reduced pyocyanin production, decreased motility, poor biofilm formation and absent paralysis of Caenorhabditis elegans. Furthermore, a genome-wide transcriptome study suggested that the level of lasI and rhlI transcription together with 36 well known QS regulated genes was significantly (≥10-fold) affected in P. aeruginosa strains expressing the bpiB09 gene in pBBR1MCS-5. Thus AHL oxidoreductases could be considered as potent tools for the development of quorum quenching strategies

Psychosocial Risks in the Workplace: An Increasing Challenge for German and International Health Protection

Occupational health in a changing world has to face up to psychosocial risks to protect the health of employees now and in the future. Faster production, service and communication processes, a service- and knowledge-based society, an increasing proportion of intellectual work, growing complexity of work-related demands, new technologies and constant availability, mobility demands, and job insecurity contribute to the problem of psychosocial risks in the workplace. Psychosocial risks affect both physical and psychosocial health. There is scientifi c evidence of the link between psychosocial work-related stress and cardiovascular diseases, affective disorders or musculoskeletal disorders, especially chronic back pain. The Framework Directive on Safety and Health makes it very clear that employers are obliged “to ensure the safety and health of workers in every aspect relating to work”. In spite of these far reaching obligations, a kind of taboo sometimes makes it hard to focus on topics that have psychosocial implications. A large number of models, instruments and methods are now available to gauge psychosocial risks in the workplace. Given the clear contrast between knowledge and application, there is not a lack of knowledge in this regard, but rather a lack of application. In Germany, statutory accident insurance institutions are guided by two key principles: putting prevention before rehabilitation and rehabilitation before compensation. To prevent work-related health risks the BG RCI has developed several prevention tools to help employers and employees deal with psychosocial risks in the workplace.Moderna medicina rada mora se suočiti s psihosocijalnim rizicima kako bi se sada i ubuduće zaštitilo zdravlje radnika. Brža proizvodnja, uslužni i komunikacijski procesi, društvo koje se temelji na uslugama i znanju, veći intelektualni napor, rastuća složenost zahtjeva povezanih s radom, novi tehnološki postupci, stalna raspoloživost, zahtjevi mobilnosti i nesigurnost posla doprinose psihosocijalnim opasnostima na radnom mjestu. Postoje znanstveni dokazi koji idu u prilog povezanosti radnoga psihosocijalnog stresa i afektivnih ili mišićno-koštanih poremećaja, a naročito kroničnih bolova u leđima. U okvirnoj Direktivi o sigurnosti i zdravlju izrijekom se navodi da poslodavci imaju obvezu “zajamčiti sigurnost i zdravlje radnika u svim radnim aspektima”. Unatoč takvim dalekosežnim obvezama postoje određeni tabui zbog kojih se ponekad teško usredotočiti na teme koje imaju psihosocijalne implikacije. Postoji veliki broj modela, instrumenata i metoda kojima se u današnje vrijeme mogu mjeriti radni psihosocijalni rizici. S obzirom na to da postoji jasna razlika između samog znanja i njegove primjene, možemo reći da u ovom smislu ne nedostaje znanje, već primjena postojećega znanja. Njemačke državne osiguravajuće kuće slijede dva ključna načela: stavljaju sprječavanje ispred rehabilitacije, a rehabilitaciju ispred kompenzacije. Kako bi se spriječili radni zdravstveni rizici, njemačka državna osiguravajuća ustanova za sirovine i kemijsku industriju (BG RCI) osmislila je nekoliko preventivnih mjera kojima nastoji pomoći poslodavcima i zaposlenicima u suočavanju s psihosocijalnim rizicima na radnom mjestu