Energy limitation of cyanophage development : implications for marine carbon cycling

RJP was in receipt of a Natural Environment Research Council (NERC) PhD studentship and a Warwick University IAS Fellowship. This work was also supported in part by NERC grant NE/N003241/1 and Leverhulme Trust grant RPG-2014-354 to A.D.M., D.J.E., and D.J.S.Marine cyanobacteria are responsible for ~25% of the fixed carbon that enters the ocean biosphere. It is thought that abundant co-occurring viruses play an important role in regulating population dynamics of cyanobacteria and thus the cycling of carbon in the oceans. Despite this, little is known about how viral infections ‘play-out’ in the environment, particularly whether infections are resource or energy limited. Photoautotrophic organisms represent an ideal model to test this since available energy is modulated by the incoming light intensity through photophosphorylation. Therefore, we exploited phototrophy of the environmentally relevant marine cyanobacterium Synechococcus and monitored growth of a cyanobacterial virus (cyanophage). We found that light intensity has a marked effect on cyanophage infection dynamics, but that this is not manifest by a change in DNA synthesis. Instead, cyanophage development appears energy limited for the synthesis of proteins required during late infection. We posit that acquisition of auxiliary metabolic genes (AMGs) involved in light-dependent photosynthetic reactions acts to overcome this limitation. We show that cyanophages actively modulate expression of these AMGs in response to light intensity and provide evidence that such regulation may be facilitated by a novel mechanism involving light-dependent splicing of a group I intron in a photosynthetic AMG. Altogether, our data offers a mechanistic link between diurnal changes in irradiance and observed community level responses in metabolism, i.e., through an irradiance-dependent, viral-induced release of dissolved organic matter (DOM).Publisher PDFPeer reviewe

Smart Fabrication QM - Neue Produktionskonzepte fuer die Halbleiterfertigung. Qualitaetsmanagement fuer neue Produktionskonzepte Abschlussbericht

The partners within the research cooperation with the IC manufactures BOSCH, SIEMENS, TEMIC, THESYS (X-Fab) and ZMD as well as the FhG. The objective of the cooperation was to find new and advanced methods for quality and reliability purposes for semiconductor fabs. Within the dynamic and fast changing market of ASICs, quick and flexible development and production times combined with quality ensuring actions are the keys of economy. The cooperation aimed to work out methods for a flexible, fast, and favourable quality assurance especially for ASICs in a 3 years industrial research and development project useful for all project partners. Detailed investigations in the areas of wafer level monitoring, reliability tests on typical circuit elements, development of optimised qualification procedures, and the work for / analyses of defect management strategies bred great experiences for all partners and gave the start for different new approaches for further optimisation actions. (orig.)SIGLEAvailable from TIB Hannover: F00B452 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung (BMBF), Bonn (Germany)DEGerman