N-Acetyl-L-glutamate kinase (NAGK) catalyzes the rate-limiting step in the ornithine/arginine biosynthesis pathway in eukaryotic and bacterial oxygenic phototrophs. NAGK is the most highly conserved target of the PII signal transduction protein in Cyanobacteria and Archaeplastida (red algae and Chlorophyta). However, yet there is still much to be learnt on how NAGK is regulated in vivo. The use of unicellular green Chlamydomonas reinhardtii as a model system has already been instrumental in identifying several key regulation mechanisms that control nitrogen (N) metabolism. With a combination of molecular-genetic and biochemical approaches, we show the existence of the complex CrNAGK control at transcriptional level, which is dependent on N source and N availability. In growing cells, CrNAGK requires CrPII to properly sense the feedback inhibitor arginine. Moreover, we provided primary evidence that CrPII is only partly responsible for regulating CrNAGK activity to adapt to changing nutritional conditions. Collectively, our results suggest that in vivo CrNAGK is tuned at transcriptional and post-translational levels, and CrPII and additional as yet unknown factor(s) are integral parts of this regulation.

Increasing the effectiveness of eradication therapy is an important task of gastroenterology. The aim was to evaluate the efficacy and safety of postbiotic (metabiotic) contained inactivated Limosilactobacillus reuteri DSM 17648 (Pylopass™; Helinorm™) as adjuvant treatment for Helicobacter pylori eradication in patients with functional dyspepsia (FD). This randomized, double-blind, placebo-controlled, multicenter, parallel study included H. pylori positive patients with FD. The postbiotic group received Pylopass 200 mg bid for 14 days in combination with the eradication therapy (esomeprazole 20 mg bid + amoxicillin 1000 mg bid + clarithromycin 500 mg bid for 14 days) and another 14 days after completion of eradication therapy. The eradication efficiency was 96.7% for the postbiotic group versus 86.0% for the placebo group (P=0.039). Both groups showed significant improvements in quality of life and reduction of most gastrointestinal symptoms with no significant differences between groups. The overall number of digestive adverse effects in the postbiotic group was lower than in the placebo group. Serious adverse effects were not registered. The postbiotic (metabiotic) contained inactivated L. reuteri DSM 17648 significantly improves the effectiveness of H. pylori eradication therapy in FD and decreases overall number of digestive adverse effects of this therapy.