caa a22 4500 475746996 CHVBK 20180406123516.0 cr unu---uuuuu 170329e20001101xx s 000 0 eng 10.1007/s002840010149 doi (NATIONALLICENCE)springer-10.1007/s002840010149 Schmitz Ruth A. Institut für Mikrobiologie und Genetik, Universität Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany, DE aut Internal Glutamine and Glutamate Pools in Klebsiella pneumoniae Grown Under Different Conditions of Nitrogen Availability [Elektronische Daten] [Ruth A. Schmitz] Internal pool sizes of glutamine and glutamate in Klebsiella pneumoniae grown under nitrogen limitation or nitrogen sufficiency were measured to study the signal transduction of external nitrogen limitation. K. pneumoniae cells were grown in an anaerobic, ammonium-limited chemostat culture. At a growth rate of 0.217 h−1, the steady state ammonium concentration in the culture was 55 μm, correlating with repression of the nitrogen fixation (nif) genes. At growth rates below 0.138 h−1, the ammonium concentration in the culture dropped below 0.5 μm and the nif genes became derepressed. During the transition from nitrogen sufficiency to nitrogen limitation, the internal glutamine pool in K. pneumoniae decreased by a factor of approximately 6. The glutamate pool, however, remained stable. Similarly, in anaerobic batch cultures with different limiting nitrogen sources, the glutamine pool generally decreased by a factor of 7 to 9 when nif gene derepression was achieved. All the limiting nitrogen sources used resulted in decreased growth rates compared with growth under nitrogen excess, suggesting an inverse relationship between glutamine pool size and doubling time. These studies indicate that K. pneumoniae perceives external nitrogen limitation as internal glutamine limitation. Springer-Verlag New York Inc., 2000 https://doi.org/10.1007/s002840010149 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002840010149 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Schmitz Ruth A. Institut für Mikrobiologie und Genetik, Universität Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer