Collapse and hybridization of RNA: view from replica technique approach.

The replica technique method is applied to investigate the kinetic behavior of the coarse-grained model for the RNA molecule. A non-equilibrium phase transition of second order between the glassy phase and the ensemble of freely fluctuating structures has been observed. The non-equilibrium steady state is investigated as well and the thermodynamic characteristics of the system have been evaluated. The non-equilibrium behavior of the specific heat is discussed. Based on our analysis, we point out the state in the kinetic pathway in which the RNA molecule is most prone to hybridization.

Microbiome changes associated with sustained eradication of Clostridium difficile after single faecal microbiota transplantation in children with and without inflammatory bowel disease.

BACKGROUND: Little data are available regarding the effectiveness and associated microbiome changes of faecal microbiota transplantation (FMT) for Clostridium difficile infection (CDI) in children, especially in those with inflammatory bowel disease (IBD) with presumed underlying dysbiosis. AIM: To investigate C. difficile eradication and microbiome changes with FMT in children with and without IBD. METHODS: Children with a history of recurrent CDI (≥3 recurrences) underwent FMT via colonoscopy. Stool samples were collected pre-FMT and post-FMT at 2-10 weeks, 10-20 weeks and 6 months. The v4 hypervariable region of the 16S rRNA gene was sequenced. C. difficile toxin B gene polymerase chain reaction was performed. RESULTS: Eight children underwent FMT for CDI; five had IBD. All had resolution of CDI symptoms. All tested had eradication of C. difficile at 10-20 weeks and 6 months post-FMT. Pre-FMT patient samples had significantly decreased bacterial richness compared with donors (P = 0.01), in those with IBD (P = 0.02) and without IBD (P = 0.01). Post-FMT, bacterial diversity in patients increased. Six months post-FMT, there was no significant difference between bacterial diversity of donors and patients without IBD; however, bacterial diversity in those with IBD returned to pre-FMT baseline. Microbiome composition at 6 months in IBD-negative patients more closely approximated donor composition compared to IBD-positive patients. CONCLUSIONS: FMT gives sustained C. difficile eradication in children with and without IBD. FMT-restored diversity is sustained in children without IBD. In those with IBD, bacterial diversity returns to pre-FMT baseline by 6 months, suggesting IBD host-related mechanisms modify faecal microbiome diversity.