Viruses infect every living organism on the planet, but not every habitat has been explored for their presence. The igneous ocean crust had not yet been examined for viruses, but seek and ye shall find: there are plenty of viruses under the seas. The oceanic basement is an enormous ecosystem that lies at the bottom of …
When giant viruses were discovered – with genomes much larger than any previously seen – some suggested that they had descended from a fourth domain of life (the current three are bacteria, archaea, and eukaryotes). Part of the reason for such a claim was the finding of homologs of bacterial and eukaryotic genes, including molecules involved …
The plaque assay – my favorite assay in the world – is a time-honored procedure to determine the number of viruses in a sample, and to establish clonal virus stocks. The linear relationship between the number of infectious particles and the plaque count (illustrated; image credit) shows that one infectious particle is sufficient to initiate infection. Despite the …
If you have ever received a blood transfusion, along with the red blood cells, leukocytes, plasma and other components, you also were infused with a collection of viruses. A recent study of the blood virome of over 8,000 healthy individuals revealed 19 different DNA viruses in 42% of the subjects. Viral DNA sequences were identified among the genome …
A key step in sexual reproduction is the fusion of haploid cells to form a diploid zygote, yet the molecular mechanism underlying this joining of cells is poorly understood. Two studies reveal amazing similarities between proteins required for fusion of sperm and egg, and virus with host cells. A screen for genes that cause male sterility in the flowering plant Arabidopsis led to …
The obligate intracellular bacteria Wolbachia (pictured), which infects 40% of arthropods, can manipulate its host to ensure its maintenance in the population. An example is cytoplasmic incompatibility, which occurs when infected males mate with uninfected females, and causes embryonic lethality (mating with an infected female produces viable offspring). Two Wolbachia genes responsible for this phenotype have been …
