We successfully recovered PHB from transconjugants prepared from nitrogen-depleted medium without sugar supplementation in which PHB reached approximately 7% (w/w) of the dry cell weight, showing a value of 12-fold higher productivity in the transconjugant than that in the control strain.
Cells were precultured in minimal medium without sugar.
YNB medium without sugar was used as negative control, and with glucose as positive control.
Recently it has been shown that the selection of transgenic plant lines containing a kanamycin marker gene can be done by culturing the seedlings on rockwool saturated with MS medium without sugar but containing the selective agent [ 11].
Seven mutant strains were selected (based on ammonia assay) and further evaluated for growth rate, ammonia and oil production, soluble protein content, and morphology when grown on liver infusion medium (without sugars), and for growth on various substrates.
Seven mutant strains, designated A, B, B2, C, D, E, and F, were selected (ammonia assay) and further evaluated for growth rate, ammonia and oil production, and soluble protein content on liver infusion medium (without sugars) and for growth on various substrates.
In control experiments, no difference in the cell division rate of any of the GAS strains was observed during planktonic growth in medium without added sugar or medium supplemented with 30 mM glucose (data not shown).
The increased biofilm forming capacity in the presence of 30 mM glucose was found to be a consequence of the environmental acidification resulting from sugar consumption during bacterial growth, as a similar FCT-dependent biofilm phenotype could be achieved by lowering the starting pH of the medium without any sugar supplementation, but not in buffered medium containing 30 mM glucose.
The grain were then incubated in vitro on Heller medium without added sugar or hormone (Agar 7 g/l), at room temperature (25°C).
Subsequently, _seedlings were transferred to liquid MS/2 growth medium without any sugar and further grown for 24 h under weak agitation (60 rpm) and constant light before being treated with 3% sucrose or 3% glucose or 3% mannitol (stock solution of 30% in water) or just with water as control for 4 h.
Then, Treg were transferred into a co-culture with Teff at a cell ratio of 1 5 (15 000 Treg:75 000 Teff in 100 μl volume per well), and 30 m m-lactose (Fluka® Analytical), 30 m m-sucrose (Fisher Scientific) or culture medium without added sugars was added to the cultures.
