Energy Metabolism of Rickettsia typhi : Pools of Adenine Nucleotides and Energy Charge in the Presence and Absence of Glutamate
- 1 June 1978
- journal article
- research article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 134 (3) , 884-892
- https://doi.org/10.1128/jb.134.3.884-892.1978
Abstract
The obligate intracellular bacterium Rickettsia typhi was examined for its ability to generate and maintain an adenylate energy charge in an extracellular environment. Freshly purified organisms were incubated, at 34°C and pH 7.4, with or without glutamate and various other metabolites, and the levels of ATP, ADP, and AMP were determined. Of the metabolites tested, glutamate and glutamine were the most effective for the generation of ATP. In the presence of glutamate, there was a rapid increase in the level of ATP, followed by a moderate decrease during 150 min of incubation. The energy charge increased from a level of 0.2 to 0.5 to about 0.7 to 0.75, and then slowly declined to about 0.45 to 0.6. In the absence of glutamate, after an occasional initial surge in ATP level as the temperature was changed from 4 to 34°C, there was a sharp decline in both ATP and energy charge (to 0.1 and sometimes to 0.01). The rickettsiae maintained their ability to regenerate their energy charge upon the addition of glutamate for about 30 min, but this ability declined with further incubation. In contrast to Escherichia coli , the decline in ATP in R. typhi was accompanied by a sharp increase in the level of AMP and the total adenylate pool. No adenine or adenosine was recovered from rickettsiae incubated with labeled AMP, ADP, or ATP. From these experiments and the demonstration reported elsewhere that rickettsiae transport the adenine nucleotides, it can be concluded that the adenylate energy charge in R. typhi is governed by the salvage of the adenine nucleotides rather than their unphosphorylated precursors. Thus, R. typhi undergoes greater shifts in energy charge than other bacteria, a phenomenon which may account for their instability in an extracellular environment. Under optimal conditions the adenylate energy charge of R. typhi approaches levels that border on those generally regarded as adequate for growth.This publication has 33 references indexed in Scilit:
- Purine and pyrimidine ribonucleotide contents of rat liver and hepatoma 3924A and the effect of ischemiaLife Sciences, 1976
- Physiological characteristics of chemostatically grownCitrobacter freundii as a function of the specific growth rate and type of nutrient limitationFolia Microbiologica, 1976
- Assay of picomole amounts of ATP, ADP, and AMP using the luciferase enzyme systemAnalytical Biochemistry, 1975
- Biochemical Function and Homeostasis: The Payoff of the Genetic ProgramPublished by Springer Nature ,1975
- REGULATION OF ENZYME FUNCTIONAnnual Review of Microbiology, 1969
- Inhibition of Haemaggregation by Lepromin and Other Mycobacterial SubstancesNature, 1967
- Metabolic Activity of Purified Suspensions of Rickettsia rickettsiNature, 1967
- [40] Thin-layer separation methods for nucleic acid derivativesPublished by Elsevier ,1967
- PROTEIN MEASUREMENT WITH THE FOLIN PHENOL REAGENTJournal of Biological Chemistry, 1951
- RESPIRATION OF TYPHUS RICKETTSIAEThe Journal of Experimental Medicine, 1949