L-Glutamine formation by Flavobacterium rigense.

A penicillin-resistant mutant of Flavobacterium rigense designated as strain 703, FERM-P no. 3628, was obtained after ultraviolet treatment of F. rigense FERM-P no. 3556. The parent strain produces 0-2-hydroxypropylhomoserine from 1,2-propanediol. The mutant was found to be a good producer of L-glutamine. The physiological characteristics of strain 703 were different from the general group of L-glutamic acid-producing bacteria. Strain 703 required L-tryptophan and thiamine but not biotin for its growth. L-Glutamine formation on a specific basis, however, was independent of L-tryptophan and thiamine. Biotin and penicillin were also not effective. Only ammonium fumarate acted as an effective factor on L-glutamine formation. Accumulation of L-glutamine by strain 703 was 10 mg/ml at 30 degrees C for 48 h in a chemically defined medium containing 3% diammonium fumarate.     

Light-Regulated Translocation of Cytoplasm in Green Alga Dichotomosiphon

Chloroplasts and other cytoplasmic granules in the freshwatercoenocytic green alga Dichotomosiphon tuberosus streamed bidirectionallyalong the longitudinal axis of its tubular body. In responseto light stimuli, the organelles migrated toward the apicalregions and accumulated there. In the dark, they migrated towardthe basal regions and stayed there. The cytoplasmic streamingand the light-regulated movement were inhibited by the presenceof 5 x 10^–4 M colchicine, but not by 100µg/ml cytochalasinB. Local illumination with blue light caused reversible accumulationof the organelles in the illuminated zone. Single arrays ofmicrotubules were found in the ectoplasmic layer of the alga,and both single and bundle arrays in the endoplasm. The endoplasmicmicrotubules disintegrated when the alga was treated for 24h with colchicine. The involvement of the microtubules in themotive force generation for the bidirectional streaming andtranslocational movement of the organelles is discussed. (Received December 27, 1985; Accepted April 16, 1986)