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 …
Transmissible spongiform encephalopathies (TSEs) are rare, but always fatal, neurodegenerative disorders of humans and other mammals. They are characterized by long incubation periods, spongiform changes in the brain associated with loss of neurons, and the absence of host responses. TSEs are caused by infectious proteins called prions. Insight into how prions cause TSEs comes from the observation that …
A study of sexual transmission of Zika virus among mice (link to paper) demonstrates beautifully that viral nucleic acid detected by polymerase chain reaction (PCR) is not the same as infectious virus. Male mice were infected with Zika virus and then mated with female mice. Efficient sexual transmission of the virus from males to females was observed. This …
Bacteriophages are the most abundant biological entities on Earth. There are 1031 of them on the planet, and they infect 1023 to 1025 bacteria every second. That’s a lot of lysis, and it leads to the release of huge quantities of DNA that can be taken up by other organisms, leading to new traits. It …
You might recall learning in high school biology that bacteriophage infection of a host can lead to either replication and cell lysis, or integration of the viral genome into the host (illustrated). The latter event, called lysogeny, spares the host from virus induced killing. For some phages, the decision between lysis and lysogeny appears to be communicated …
A unique feature of eukaryotic cells, which distinguishes them from bacteria, is the presence of a membrane-bound nucleus that contains the chromosomal DNA (illustrated; image credit). Surprisingly, a nucleus-like structure that forms during viral infection of bacteria is the site of viral DNA replication (link to paper). During infection of Pseudomonas bacteria with the phage 2O1phi2-1, a …
