In this study the technique of energy-filtering transmission electron microscopy was applied to localize cyanophycin (CGP) in recombinant strains of Ralstonia eutropha. Since CGP is a polymer consisting of the amino acids aspartate and arginine, which functions as a temporary nitrogen reserve that is deposited as insoluble inclusions in the cytoplasm of the cell, its nitrogen content is significantly higher than that of the other cell matter. In this study, we recorded nitrogen distribution maps, which represent the location of CGP in ultrathin sections of resin-embedded cells of recombinant strains of R. eutropha expressing the cyanophycin synthetase of Anabaena sp. strain PCC 7120. Furthermore, the existence of nitrogen in CGP granules was additionally proven by recording electron energy-loss spectra. The samples of R. eutropha H16 (pBBR1MCS-2::cphA17120) revealed a second type of granule, which does not show nitrogen in the corresponding maps and which can be identified as an inclusion containing poly(3-hydroxybutyric acid). The methods applied in this study are suitable to identify storage compounds with elevated nitrogen contents and to reveal their location in the bacterial cell. The methods are also very helpful to distinguish between inclusions of different chemical compositions that occur both at the same time in the cells but cannot or only hardly be distinguished by other methods.

The H2-oxidizing lithoautotrophic bacterium Ralstonia eutropha H16 is a metabolically versatile organism capable of subsisting, in the absence of organic growth substrates, on H2 and CO2 as its sole sources of energy and carbon. R. eutropha H16 first attracted biotechnological interest nearly 50 years ago with the realization that the organism's ability to produce and store large amounts of poly[R-(–)-3-hydroxybutyrate] and other polyesters could be harnessed to make biodegradable plastics. Here we report the complete genome sequence of the two chromosomes of R. eutropha H16. Together, chromosome 1 (4,052,032 base pairs (bp)) and chromosome 2 (2,912,490 bp) encode 6,116 putative genes. Analysis of the genome sequence offers the genetic basis for exploiting the biotechnological potential of this organism and provides insights into its remarkable metabolic versatility.

The H 2 -oxidizing lithoautotrophic bacterium Ralstonia eutropha H16 is a metabolically versatile organism capable of subsisting, in the absence of organic growth substrates, on H 2 and CO 2 as its sole sources of energy and carbon. R. eutropha H16 first attracted biotechnological interest nearly 50 years ago with the realization that the organism's ability to produce and store large amounts of poly[ R -(–)-3-hydroxybutyrate] and other polyesters could be harnessed to make biodegradable plastics. Here we report the complete genome sequence of the two chromosomes of R. eutropha H16. Together, chromosome 1 (4,052,032 base pairs (bp)) and chromosome 2 (2,912,490 bp) encode 6,116 putative genes. Analysis of the genome sequence offers the genetic basis for exploiting the biotechnological potential of this organism and provides insights into its remarkable metabolic versatility.