Effect of infection with iridovirus type 6 on invertebrate cell phospholipids

Invertebrate Iridoviruses: A Glance over the Last Decade

Members of the family Iridoviridae (iridovirids) are large dsDNA viruses that infect both invertebrate and vertebrate ectotherms and whose symptoms range in severity from minor reductions in host fitness to systemic disease and large-scale mortality. Several characteristics have been useful for classifying iridoviruses; however, novel strains are continuously being discovered and, in many cases, reliable classification has been challenging. Further impeding classification, invertebrate iridoviruses (IIVs) can occasionally infect vertebrates; thus, host range is often not a useful criterion for classification. In this review, we discuss the current classification of iridovirids, focusing on genomic and structural features that distinguish vertebrate and invertebrate iridovirids and viral factors linked to host interactions in IIV6 (Invertebrate iridescent virus 6). In addition, we show for the first time how complete genome sequences of viral isolates can be leveraged to improve classification of new iridovirid isolates and resolve ambiguous relations. Improved classification of the iridoviruses may facilitate the identification of genus-specific virulence factors linked with diverse host phenotypes and host interactions.

Lipid composition of Spodoptera frugiperda (Sf9) and Trichoplusia ni (Tn) insect cells used for baculovirus infection

The lipid composition of two different insect cell lines from Spodoptera frugiperda (Sf9) and Trichoplusia ni (Tn) which are established cell lines for infection with recombinant baculovirus was analyzed by high-performance liquid chromatography and gas-liquid chromatography. The major phospholipids found were phosphatidylcholine and phosphatidylethanolamine, the major mono-unsaturated fatty acids were oleic acid and palmitoleic acid, the major saturated fatty acid was stearic acid. The cholesterol to phospholipid ratio was demonstrated to be lower than in mammalian cell lines. Infection with a recombinant baculovirus Autographa californica resulted in increased levels of phosphatidylcholine in the insect cells. The baculovirus/insect cell system has become a popular system for heterologous protein production. Functional changes of membrane proteins produced in these two cell lines might be correlated to a different lipid profile of their cellular membranes.

Outer-membrane permeability of bacteria

Gram-negative bacteria evolved to survive under the conditions in which a number of hazardous compounds are abundant. The outer membrane which protects the cell interior acts as a barrier against such hazardous agents, yet the cells must incorporate the chemicals that are essential for the cellular activity. The devices that Gram-negative bacteria developed to incorporate such essence are the transmembrane pores. These pores could be subdivided into three categories: (1) pore made of porins has a weak solute selectivity; (2) pore made of lamB protein and tsx proteins hold intermediate solute specificity. and (3) pores for the diffusion of vitamin B12 and ferric ion-chelator complexes have a tight solute specificity. Porins are identified from a number of Gram-negatives and from the outer membrane of mitochondria of various sources. Studies on the diffusion properties of these outer-membrane proteins provided essential information to understand membrane transports.