ISSN:
1432-072X
Keywords:
ppGpp
;
Nitrogen starvation
;
Anacystis nidulans
;
Cyanobacterium
;
Guanosine tetraphosphate
;
GTP
;
ATP
;
Nitrate starvation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The effect of nitrate deprivation on cell growth and nucleotide level was studied in Anacystis nidulans. A 10-fold reduction in nitrate level resulted in a drastic slowdown of growth. Upon addition of nitrate to the starving cultures, after a lag period, the cells resumed growth. Nutritional shift-down induced a transitory expansion of the guanosine tetraphosphate (ppGpp) pool, preceeded by a transitory increase in GTP and ATP concentrations. After having reached peak values, the concentration of ppGpp, GTP and ATP dropped to the respective base levels. The expansion of the ppGpp pool was found to be due to an increase in ppGpp synthesis, rather than to a decrease in ppGpp breakdown. After nutritional shift-up, no decrease in the ppGpp level was found. In starving cells, a decrease in free amino acids was observed to occur concomitantly with the expansion of the ppGpp pool. The level of free amino acids started to increase simultaneously with the contraction of the ppGpp pool.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00406458
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