The Van Etten laboratory investigates a wide range of topics associated with the molecular biology, biochemistry, genetics, bioinformatics, and ecology of large viruses that infect certain unicellular, eukaryotic chlorella-like green algae. Chloroviruses, which were discovered by our laboratory, are found in freshwater from all over the world and they have many interesting and unexpected properties. One interesting property of the chloroviruses is that they are among the largest viruses known and their genomes contain as many as 16 tRNA genes and 450 protein-encoding genes, including many not previously found in viruses, e.g., genes encoding DNA restriction and modification enzymes, hyaluronan and chitin biosynthetic enzymes, five polyamine biosynthetic enzymes, and potassium ion and aquaglyceroporin channels, and potassium ion and calcium ion transporters. The proteins encoded by many of these viruses are either the smallest or among the smallest proteins of their class. Consequently, some of the viral proteins are the subject of intensive biochemical and structural investigation. The chloroviruses differ from all other known viruses in the way that they synthesize the glycans attached to their major capsid proteins. Unlike other viruses, the chloroviruses encode most, if not all, of the machinery involved in the synthesis of the glycans and the process occurs in the cytoplasm rather than in the endoplasmic reticulum and Golgi apparatus.  Together with two glycobiology groups in Italy, some of the glycan structures have been solved and they differ from anything present in the databases. In addition, we are starting to identify the virus-encoded enzymes involved in the glycosylation process. In a separate project we have recently discovered that some protists can grow and multiply using chloroviruses as their only food source. Thus, viruses need to be considered as part of the food chain. Finally, in a completely unexpected finding, we have discovered that the chloroviruses may be associated with amyotrophic lateral sclerosis diseases like Lou Gehrig’s disease. The viruses can replicate slightly in mice macrophage cells and exposure to one of the chloroviruses produced cognitive behavior changes in mice that are statistically significantly.