@article{mbs:/content/journal/micro/10.1099/00221287-136-1-157, author = "Fougère, F. and Le Rudulier, D.", title = "Uptake of glycine betaine and its analogues by bacteroids of Rhizobium meliloti", journal= "Microbiology", year = "1990", volume = "136", number = "1", pages = "157-163", doi = "https://doi.org/10.1099/00221287-136-1-157", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-136-1-157", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", abstract = "Bacteroids isolated from alfalfa nodules induced by Rhizobium meliloti 102F34 transported glycine betaine at a constant rate for up to 30 min. Addition of sodium salts greatly increased the uptake activity, whereas other salts or non-electrolytes had less effect. The apparent K m for glycine betaine uptake was 8·3 μm and V was about 0·84 nmol min-1 (mg protein)-1 in the presence of 200 mm-NaCl which gave maximum stimulation of the transport. Supplementing bacteroid suspensions with various energy-yielding substrates, or ATP, did not increase glycine betaine uptake rates. The uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP), and the respiratory inhibitor potassium cyanide strongly inhibited glycine betaine uptake, but arsenate was totally inactive. Glycine betaine transport showed considerable structural specificity: choline, proline betaine, γ-butyrobetaine and trigonelline did not competitively inhibit the system, although choline and proline betaine were transported by bacteroids. Both a high-affinity activity and a low-affinity activity were found for choline uptake. These osmoprotective compounds might have a significant role in the maintenance of nitrogenase activity in bacteroids subjected to salt stress.", }