Viruses Structural organization

The satellite ssRNA viruses are a group of ssRNA icosahedral viruses, which are the satellites to certain plant viruses (Pritsch and Mayo, 1989). Satellite tobacco necrosis virus (STNV), a satellite virus to tobacco necrosis virus, was in fact one of the first icosahedral virus structures to be determined by X-ray crystallography (Liljas et al, 1982). In more recent years, two other satellite plant viruses, satellite tobacco mosaic virus (STMV) (Larson et al, 1993, 1998) and satellite panicum mosaic virus (SPMV) (Ban and McPherson, 1995), have been determined. These are perhaps the simplest and smallest icosahedral viruses whose structures have been determined by X-ray crystallography. Of relevance to our discussion is the structure of STMV determined to 1.8-A resolution, which shows extraordinary details about genome organization (Larson et al, 1998 Larson and McPherson, 2001). 

Fig. 5. Structural organization of the genome in dsDNA viruses revealed by cryo-EM techniques. Cross-sectional views from the cryo-EM reconstructions of (a) P22 (Zhang etai.,2000) and (b) PRDl (Martin eiai., 2001). Concentric rings of DNA, with aspacing of 25 A, are seen inside the capsid layers (indicated by white arrows in each). PRDl virus has a lipid bilayer (black arrow) between the genome and the capsid layer. Scale bars 100 A.

Genome replication/packaging, in double-stranded RNA viruses, 234 Genome size, 379-380 Genome structural organization... 

A., and Rosenthal, P.B. (2010) Structural organization of a filamentous influenza A virus. Proceedings of the National Academy of Sciences of the United States of America, 107, 10685-10690. 

Choi, H.-K., et al. Structure of Sindbis virus core protein reveals a chymotrypsin-like serine proteinase and the organization of the virion. Nature 354 37-43, 1991. 

Moulds and yeasts show varying responses to biocides. These organisms are often important in the pharmaceutical context because they may cause spoilage of formulated products. Various types of protozoa are potentially pathogenic and inactivation by biocides may be problematic. Viral response to biocides depends upon the type and structure of the virus particle and on the nature of the biocide. 

Domino reactions are also used in the development of new and potent pharmaceuticals, which is an important target in organic synthesis. The following example by Katoh and coworkers presents an impressive approach to the tetracyclic core structure of the novel anti-influenza A virus agent, stachyflin (1-152), using as key feature a new Lewis acid-induced domino epoxide-opening/rearrangement/cy-... 

Eukaryote Cell or organism with membrane-bound, structurally discrete nucleus and other well-developed subcellular compartments. Eukaryotes include all organisms except viruses, bacteria, and blue-green algae (see also prokaryote). 

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