Structure and replication cycle of a virus infecting climate-modulating algaEmiliania huxleyi

The globally distributed marine alga Emiliania huxleyi produces reflective calcite disks (coccoliths) that increase the albedo of ocean water and thus reduce the heat absorption in the ocean, which cools the Earth’s climate. The population density of E. huxleyi is restricted by nucleocytoplasmic large DNA viruses, including E. huxleyi virus 201 (EhV-201). Despite the impact of E. huxleyi viruses on the climate, there is limited information about their structure and replication. Here we show that the dsDNA genome inside the EhV-201 virion is protected by an inner membrane, capsid, and outer membrane decorated with numerous transmembrane proteins. The virions are prone to deformation, and parts of their capsids deviate from the icosahedral arrangement. EhV-201 virions infect E. huxleyi by using their fivefold vertex to bind to a host cell and fuse the virus’s inner membrane with the plasma membrane. Whereas the replication of EhV-201 probably occurs in the nucleus, virions assemble in the cytoplasm at the surface of endoplasmic reticulum-derived membrane segments. Genome packaging initiates synchronously with the capsid assembly and completes through an aperture in the forming capsid. Upon the completion of genome packaging, the capsids change conformation, which enables them to acquire an outer membrane by budding into intracellular vesicles. EhV-201 infection induces a loss of surface protective layers from E. huxleyi cells, which allows the continuous release of virions by exocytosis. Our results provide insight into how EhVs bypass the surface protective layers of E. huxleyi and exploit the organelles of an infected cell for progeny assembly

Biosenzory s povrchovými plazmony: Dnes a zítra

This paper reviews the present state of the art and recent advances in the development of SPR sensors and presents selected results of SPR sensor research at the Institute of Photonics and Electronics, Prague

Surface plasmon resonance biosensors: present and future

Optical biosensors based on the surface plasmon resonance (SPR) have become important tool for real-time study of biomolecular interactions and for detection of various analytes in fields such as food safety, medical diagnostics, or environmental monitoring. This paper reviews the present state of the art in the development of SPR sensor technology, discusses emerging trends, and presents selected results of research into SPR sensors at the Institute of Photonics and Electronics, Prague

Novel surface plasmon resonance sensor based on single-mode optical fiber

Surface plasmon resonance sensor based on resonant interaction between a guided mode of a single-mode optical fiber and a surface plasmon wave supported by a thin metal overlayer is presented. Two modes of operation of the sensor based on the measurement of changes in the fiber mode attenuation and on the measurement of changes in the wavelength at which the resonance occurs are described. Theoretical analysis of the proposed sensing structure based on the equivalent planar waveguide approach and the mode expansion and propagation method is carried out. It is shown that the operation range of the sensor may be tuned by a thin dielectric overlayer. Experimental results have shown that in both the modes of operation the sensor is capable of detecting changes in the refractive index of the sensed medium below 2×10-5.</p