Algal viruses

Although most are beneficial to human health, some of these microbes can cause problems. Research in both humans and animal models has shown that microbial communities can affect many biological functions, including cognitive performance. Most studies of microbial communities and their genes, collectively known as the microbiome, have focused on bacterial and fungal communities.

DNA is extracted from samples, and then specific regions that are universal to bacteria or fungi are analyzed to distinguish the microbes. The viral components of the microbiome the virome have received less attention, largely because viruses are so diverse that there are no universal viral target regions. Recent advances, however, have made whole-genome sequencing faster and less expensive.

Thus scientists can now sequence entire viral genomes. A group led by Dr. Robert Yolken at Johns Hopkins University has been studying the links between viral infections and brain development. They were analyzing viruses taken from the throats of 33 healthy adults who were participating in a study that involved the assessment of cognitive functioning. Unexpectedly, the researchers discovered genetic sequences from Acanthocystis turfacea chlorella virus 1 ATCV ATCV-1 is a type of Chlorovirus, which infects green algae.

To further investigate, the group teamed with Dr. The team next examined the link between ATCV-1 and performance on a battery of cognitive tests. ATCV-1 was associated with decreases on tests of visual processing.

There was no difference on tests of general knowledge. Studies in people can involve many complex factors, so the scientists infected a group of mice with ATCV The HaV intein is closely related to the mimivirus intein, and both are apparently monophyletic to the archaeal inteins.

These observations suggest the occurrence of horizontal transfers of inteins between viruses of different families and between archaea and viruses and reveal that viruses might be reservoirs and intermediates in horizontal transmissions of inteins. The homing endonuclease domain of the HaV intein alleles is mostly deleted.

The mechanism keeping their sequences basically identical in HaV strains specific for different hosts is yet unknown. One possibility is that rapid and local changes in the HaV genome change its host specificity. This is the first report of inteins found in viruses infecting eukaryotic algae.