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Pseudomonas aeruginosa is an ubiquitous and opportunistic bacteria found in water, soil, plants, and immunocompromised humans. Cystic fibrosis (CF) patients are the most vulnerable population to lung colonization by these bacteria. Upon infection, choline and succinate are released from the CF lungs and are catabolized by P. aeruginosa . The bacteria accumulate inorganic polyphosphates, rather than succinate, when choline is catabolized, producing physiological and morphological changes leading to ineradicable infection. Thus, we sought to quantify the enzymes responsible for polyphosphate accumulation and to determine how choline catabolism affects energy flow and storage. Subcellular fractions showed that exo-polyphosphate phosphatase (PPX) activity resides mainly in the periplasm, and three isoenzymes of 24, 70, and 200 KD were found. The PPX activity in the periplasm of bacteria grown with choline was inhibited in an anti-competitive manner from Km 0.5 to 1 μM, and their Vmax increased from 50 to 100 nmol PO 4 ≡ /min/g of protein in succinate medium. Since PPX inhibition by choline did not explain the 3.8-fold increase in polyphosphates, we quantified the polyphosphate kinase activity, and its significant 2.4-fold increase was consistent with the accumulation. Furthermore, intracellular ATP concentration directly correlated with the energetic yield of the carbon source and was significantly higher for succinate, suggesting that the restriction of energy caused by choline catabolism may induce morphological and physiological changes to the swarm form thus facilitating their migration and tissue colonization., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

Quality evaluation of commercial inoculants is essential to warrant an adequate crop response to inoculation within a biosecurity framework. In this sense, this work is aimed at standardizing and validating the drop plate method for the enumeration of Azospirillum viable cells as an alternative to the spread plate technique, which is currently proposed in the consensus protocol of the REDCAI network. Between 14 and 25 private and public laboratories participated in three independent trials. We obtained consistent and robust results that allowed to confirm that both techniques are equivalent, concluding that the drop plate method is an alternative enumeration technique that is adequate to be included in the abovementioned consensus protocol., (Copyright © 2021 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Fibrodysplasia ossificans progressiva is a rare genetic disorder characterized by fibrotic tissue proliferation and calcification that affect body soft tissues, especially after minor traumas. Joint ankylosis and restrictive respiratory failure can be observed in the most extreme cases of the disease. Because of its rarity, diagnosis is often late and many medical actions, such as biopsy, can result iatrogenic and worsen the prognosis. Diagnosis in the neonatal period may be difficult. There is a little number of cases diagnosed at early ages. The following case concerns a child born from a mother with fibrodysplasia ossificans progressiva who had signs of the disease at birth. The presence of bilateral deformed and unusually large hallux, generally accompanied by a short and stiff neck, may help in the diagnostic process.