Cardiovagal modulation in pediatric functional gastrointestinal disorders.

BACKGROUND AND OBJECTIVES: Though reduced cardiovagal modulation accompanies adult IBS, adolescents with functional gastrointestinal disorders (FGID) have not been studied. We aim to investigate whether adolescents with FGID have reduced cardiovagal modulation. METHODS: After 10-minute supine rest, we recorded ECG for 5-minute supine and 5-minute standing without support in healthy and FGID-affected adolescents. After analysis with Kubios 2.2 for high-frequency (hf) and low-frequency (lf) heart rate variability (HRV), Wilcoxon signed-ranks test compared individual paired supine and standing HRV data, while Kruskal-Wallis and Mann-Whitney U tests compared HRV across groups. RESULTS: A total of 50 FGID subjects (90% females; median age 17 years [range 11-21]) and 22 healthy comparison group (HC) (59% females; median age 14 years [range 10-18]) participated. Both absolute and relative supine hfHRV exceeded standing in both groups. Absolute supine lfHRV was higher than standing in FGID patients and not in HCs, while relative supine lfHRV power was actually lower in both groups. Compared to HC, FGID group showed significantly lower absolute HRV, while relative HRV did not differ between groups. CONCLUSIONS: Cardiovagal modulation is lower in adolescents with FGID. This difference impacts these subjects significantly. Whether this finding reflects a cause or a consequence of FGID is unknown.

The oil-contaminated soil diazotroph Azoarcus olearius DQS-4T is genetically and phenotypically similar to the model grass endophyte Azoarcus sp. BH72.

The genome of Azoarcus olearius DQS-4T , a N2 -fixing Betaproteobacterium isolated from oil-contaminated soil in Taiwan, was sequenced and compared with other Azoarcus strains. The genome sequence showed high synteny with Azoarcus sp. BH72, a model endophytic diazotroph, but low synteny with five non-plant-associated strains (Azoarcus CIB, Azoarcus EBN1, Azoarcus KH32C, A. toluclasticus MF63T and Azoarcus PA01). Average Nucleotide Identity (ANI) revealed that DQS-4T shares 98.98% identity with Azoarcus BH72, which should now be included in the species A. olearius. The genome of DQS-4T contained several genes related to plant colonization and plant growth promotion, such as nitrogen fixation, plant adhesion and root surface colonization. In accordance with the presence of these genes, DQS-4T colonized rice (Oryza sativa) and Setaria viridis, where it was observed within the intercellular spaces and aerenchyma mainly of the roots. Although they promote the growth of grasses, the mechanism(s) of plant growth promotion by A. olearius strains is unknown, as the genomes of DQS-4T and BH72 do not contain genes for indole acetic acid (IAA) synthesis nor phosphate solubilization. In spite of its original source, both the genome and behaviour of DQS-4T suggest that it has the capacity to be an endophytic, nitrogen-fixing plant growth-promoting bacterium.