Archive for June 1st, 2012

Genome and proteome analysis of 7-7-1, a flagellotropic phage infecting Agrobacterium sp H13-3

1 June, 2012

See on Scoop.itVirology and Bioinformatics from Virology.ca

“The flagellotropic phage 7-7-1 infects motile cells of Agrobacterium sp H13-3 by attaching to and traveling along the rotating flagellar filament to the secondary receptor at the base, where it injects its DNA into the host cell.”

 

This is an interesting paper, because it describes a phage infecting Agrobacterium – and touches on a subject that has intrigued me for years, which is: How does a phage which attaches to a flagellum, get its genome inside the cell?  This throws some mud onto a previous model, which suggested a passive mode of transport like a well-oiled nut moving towards the head of a bolt, as in this case that would result in transport the other way.  Expectr more on this topic!

 

Image sourced from the paper

See on www.virologyj.com

What Do Human Parasites Do with a Chloroplast Anyway?

1 June, 2012

See on Scoop.itVirology News

“Apicomplexans are an important group of pathogens that include the causative agents of malaria, toxoplasmosis, and cryptosporidiosis. These single-celled eukaryotic parasites evolved from photosynthetic algae. A remnant chloroplast, called the apicoplast, is a telltale hold-over from this more benign past in the ocean. 1The apicoplast is essential for parasite growth and development and therefore a potential target for drug therapy. The fact that humans and animals lack chloroplasts suggests that using approaches to target the apicoplast may provide parasite specificity. What are the critical functions of the apicoplast that should be targeted? In addition to the obvious medical relevance this question has broader biological implications. Why do organisms maintain an ancient symbiotic relationship when the initial rationale for this relationship has fallen by the evolutionary wayside? A new study by Yeh and DeRisi provides important clues. Their work demonstrates that antibiotic-induced loss of the apicoplast in cultured malaria parasites can be chemically rescued by providing isopentenyl-pyrophosphate (IPP) in the medium. IPP is generated by the apicoplast resident isoprenoid biosynthesis pathway and is apparently the one apicoplast metabolite that the parasite cannot live without in the red blood cell. This finding could be of great importance for the development of drugs and vaccines. The ability to produce and maintain parasite lines that lack the apicoplast also offers exciting experimental possibilities for the future.”

 

Great review – and malaria is important enough to be considered an honorary virus (B-), so it is appropriate to cover it here.  The review also illustrates yet another aspect of the fascinating evolutionary propensity for eukaryotic algae, themsleves the result of endosymbiosis between a photosynthetic prokaryote and a eukaryote, for themselves becoming endosymbionts.

See on www.plosbiology.org