Prokaryotic Argonaute nuclease cooperates with co-encoded RNase to acquire guide RNAs and target invader DNA.

Argonautes are an evolutionary conserved family of programmable nucleases that identify target nucleic acids using small guide oligonucleotides. In contrast to eukaryotic Argonautes (eAgos) that act on RNA, most studied prokaryotic Argonautes (pAgos) recognize DNA targets. Similarly to eAgos, pAgos can protect prokaryotic cells from invaders, but the biogenesis of guide oligonucleotides that confer them specificity to their targets remains poorly understood.

DNA-targeting short Argonautes complex with effector proteins for collateral nuclease activity and bacterial population immunity.

Two prokaryotic defence systems, prokaryotic Argonautes (pAgos) and CRISPR-Cas, detect and cleave invader nucleic acids using complementary guides and the nuclease activities of pAgo or Cas proteins. However, not all pAgos are active nucleases. A large clade of short pAgos bind nucleic acid guides but lack nuclease activity, suggesting a different mechanism of action.

[Small pelvis lipoma spreading to the gluteal region].

We present a 36-year-old woman with small pelvis lipoma spreading to the gluteal region through the greater sciatic foramen. Resection of lipoma was performed via two accesses (lower median laparotomy and semilunar incision in the gluteal region). The tumor was the content of sciatic hernia that is extremely rare.

[Pancreatic mucinous cystadenoma with atypical clinical presentation].

We present a 33-year-old patient with atypical clinical course of pancreatic mucinous cystadenoma. The tumor had connection with pancreatic ductal system and led to bleeding into cystic cavity. This contributed to incorrect preoperative diagnosis of post-necrotic cyst.