METABOLIC ACTIVITY IN<i>COXIELLA BURNETII</i>

Ormsbee, Richard A.; Peacock, Marius G.

doi:10.1128/jb.88.5.1205-1210.1964

Cited by 23 publications

(16 citation statements)

References 19 publications

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“…Previous studies have shown that tricarboxylic acid cycle intermediates are preferentially metabolized by purified C. burnetii (13); however, these studies were carried out in a reaction buffer of approximately pH 7.25, a value much greater than the optimum pH at which this organism actively transports and metabolizes these substrates (5). In a similar study (15), glucose was reported not to be utilized by intact C. burnetii.…”

Section: Resultsmentioning

confidence: 92%

Stability of the Adenosine 5′-Triphosphate Pool in Coxiella burnetii : Influence of pH and Substrate

Hackstadt

Williams

1981

J Bacteriol

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The ability of Coxiella burnetii to couple oxidation of metabolic substrates to adenosine 5'-triphosphate (ATP) synthesis in axenic reaction buffers was examined. Pyruvate, succinate, and glutamate were catabolized and incorporated at the highest rates of 11 substrates tested. Glutamate oxidation, however, resulted in the greatest stability of the ATP pool and highest intracellular ATP levels over a 48-h period. At pH 4.5, the optimum for metabolism by C. burnetii, glutamate oxidation resulted in maintenance of the ATP pool at a concentration of approximately 0.7 nmol of ATP per mg of dry weight over a 96-h period. In the absence of substrate, ATP declined by 96 h to less than 0.01 nmol/mg of dry weight. When cells were maintained at pH 7.0 in the presence or absence of glutamate, ATP pools were considerably more stable, presumably due to the miniimal metabolic activity displayed by C. burnetii at pH 7. The stability of the ATP pool reflected viability as there was greater than an 8-log decrease in viable C. burnetii after incubation for 7 days at pH 4.5 in the absence of glutamate. Viability was retained in the presence of glutamate at pH 4.5 or 7.0 in the absence of any added substrate. The stability of the ATP pool was due to endogenous synthesis of ATP coupled to substrate oxidation as shown by depression of ATP levels in the presence of inhibitors of electron transport or oxidative phosphorylation. In addition, the adenylate energy charge increased from an initial value of 0.57 to 0.73 during glutamate oxidation with a concomitant rise in the total adenylate pool size. C. burnetii therefore appears able to regulate endogenous ATP levels in response to substrate availability and pH, thus effecting a conservation of metabolic energy in neutral or alkaline environments. Such a mechanism has been proposed to play a role in the resistance of C. burnetii to environmental conditions and subsequent activation upon entry into the phagolysosome in which this organism replicates.

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Section: Resultsmentioning

confidence: 92%

Stability of the Adenosine 5′-Triphosphate Pool in Coxiella burnetii : Influence of pH and Substrate

Hackstadt

Williams

1981

J Bacteriol

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“…Although metabolic activity of C. burneti was demonstrated only with considerable difficulty when whole cells were used (14), experiments with cell extracts have been quite productive. Of the 16 enzymatic activities investigated in this study, the following 10 were demonstrated in C. burneti: citrate synthase, MDH, and NAD-dependent GDH (17); NADP-dependent IDH and glucose-6-phosphate dehydrogenase (4); 6-phosphogluconate dehydrogenase (10); phosphoglucose isomerase, fructoaldolase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase (11).…”

Section: Discussionmentioning

confidence: 99%

“…These experiments and those we present indicate that there is a VOL. 14,1976 on July 16, 2020 by guest http://iai.asm.org/ Downloaded from profound difference between typhus and Q fever rickettsiae in their physiological properties. Although there is little doubt that both groups of organisms possess a functioning tricarboxylic acid cycle, only the latter appear to be capable of glucose catabolism.…”

Section: Discussionmentioning

confidence: 99%

Enzymatic activities of cell-free extracts of Rickettsia typhi

Coolbaugh¹,

Progar²,

Weiss³

1976

Infect Immun

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Cell-free extracts of Rickettsia typhi were tested for activities of enzymes of the tricarboxylic acid cycle, of glutamate catabolism, and of glycolysis. The organisms were grown in the yolk sacs of chicken embryos, harvested shortly before the time of embryo death, purified by Renografin density gradient centrifugation, and ruptured in a French pressure cell. The following enzymatic activities were demonstrated: high levels of malate dehydrogenase (MDH), moderate levels of glutamate-oxaloacetate transaminase, glutamate, succinate, and isocitrate dehydrogenases, and citrate synthase, and low levels of glutamatepyruvate transaminase. The specific activities of some of these enzymes were higher when the rickettsiae were harvested at a time of active proliferation, 3 to 4 days prior to embryo death. Rickettsial MDH was differentiated from host MDH by its migration pattern on polyacrylamide gel electrophoresis. The activities of MDH and two other dehydrogenases, demonstrable after the cells had been disrupted, were absent from purified, intact rickettsial preparations. No activity was detected for glucose-6-phosphate, 6-phosphogluconate, glyceraldehyde-3-phosphate, lactate dehydrogenases, phosphoglucose isomerase, fructoaldolase, or pyruvate kinase. Our results suggest that extracts of R. typhi that contain demonstrable enzymes involved in the catabolism of glutamate and tricarboxylic acid cycle intermediates, unlike Coxiella burneti, lack detectable glycolytic activity.The extracts of uninfected yolk sac membrane were prepared as follows. The yolk sacs of 14to 15day-old embryos were harvested and suspended in an equal volume/weight of brain heart infusion 298 on July 16, 2020 by guest http://iai.asm.org/ Downloaded from

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“…The study of bacteria with an obligate intracellular lifestyle presents a particular challenge and it can be difficult to determine and reproduce the environmental conditions required for metabolic activity. For example, initial work investigating the metabolism of Coxiella burnetii used neutral pH buffers and concluded that there was negligible activity (Ormsbee & Peacock, 1964). When acidic buffers were used, metabolism was markedly enhanced (Hackstadt & Williams, 1981).…”

Section: Reasons For 'Unculturability'mentioning

confidence: 99%

Strategies for culture of ‘unculturable’ bacteria

Vartoukian

Palmer

Wade

2010

FEMS Microbiology Letters

448

412

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Molecular ecology methods are now well established for the culture-independent characterization of complex bacterial communities associated with various environmental and animal habitats and are revealing the extent of their diversity. By comparison, it has become clear that only a small minority of microorganisms are readily cultivated in vitro, with the majority of all bacteria remaining 'unculturable' using standard methods. Yet, it is only through the isolation of bacterial species in pure culture that they may be fully characterized, both for their physiological and pathological properties. Hence, the endeavour to devise novel cultivation methods for microorganisms that appear to be inherently resistant to artificial culture is a most important one. This minireview discusses the possible reasons for 'unculturability' and evaluates advances in the cultivation of previously unculturable bacteria from complex bacterial communities. Methods include the use of dilute nutrient media particularly suited for the growth of bacteria adapted to oligotrophic conditions, and the provision of simulated natural environmental conditions for bacterial culture. This has led to the recovery of 'unculturables' from soil and aquatic environments, likely to be due to the inclusion of essential nutrients and/or signalling molecules from the native environment.

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METABOLIC ACTIVITY INCOXIELLA BURNETII

Cited by 23 publications

References 19 publications

Stability of the Adenosine 5′-Triphosphate Pool in Coxiella burnetii : Influence of pH and Substrate

Stability of the Adenosine 5′-Triphosphate Pool in Coxiella burnetii : Influence of pH and Substrate

Enzymatic activities of cell-free extracts of Rickettsia typhi

Strategies for culture of ‘unculturable’ bacteria

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