Babesiosis as a cause of fever in patients undergoing a splenectomy.

Babesiosis is an emerging infection most commonly acquired from a tick bite. We describe three hospitalized patients with fever attributable to babesiosis after a splenectomy. Splenectomy was done because of splenic enlargement due to unsuspected babesia infection in one patient and because of splenic perforation due to babesiosis in a second patient. The third patient underwent splenectomy for trauma and acquired babesiosis postoperatively from a blood transfusion. Our cases demonstrate the need to be vigilant for babesiosis in patients undergoing splenectomy.

Function of the SmpB tail in transfer-messenger RNA translation revealed by a nucleus-encoded form.

Stalled bacterial ribosomes are freed when they switch to the translation of transfer-messenger RNA (tmRNA). This process requires the tmRNA-binding and ribosome-binding cofactor SmpB, a beta-barrel protein with a protruding C-terminal tail of unresolved structure. Some plastid genomes encode tmRNA, but smpB genes have only been reported from bacteria. Here we identify smpB in the nuclear genomes of both a diatom and a red alga encoding a signal for import into the plastid, where mature SmpB could activate tmRNA. Diatom SmpB was active for tmRNA translation with bacterial components in vivo and in vitro, although less so than Escherichia coli SmpB. The tail-truncated diatom SmpB, the hypothetical product of a misspliced mRNA, was inactive in vivo. Tail-truncated E. coli SmpB was likewise inactive for tmRNA translation but was still able to bind ribosomes, and its affinity for tmRNA was only slightly diminished. This work suggests that SmpB is a universal cofactor of tmRNA. It also reveals a tail-dependent role for SmpB in tmRNA translation that supersedes a simple role of linking tmRNA to the ribosome, which the SmpB body alone could provide.