OXIDATIVE ASSIMILATION BY BACILLUS MEGATERIUM

Micrococcus sodonensis is a biotin-requiring strict aerobe that cannot utilize carbohydrates as sole sources of carbon and energy. However, addition of mannose, glucose, sucrose, or maltose to a medium on which the organism can grow resulted in an increase in total growth. M. sodonensis oxidized these sugars without induction, thus indicating the presence of constitutive enzymes for their transport, activation, and metabolism. Under appropriate nonproliferating cell conditions, glucose was readily incorporated into essential constituents of the cell. When glucose-i-C'4 and glucose-6-C'4 were oxidized by nonproliferating cells, the label was found in both the protein and nucleic acid fractions of the cell. The respiratory quotients of cells oxidizing glucose in saline and in phosphate buffer indicated assimilation of sugar carbon in buffer and virtually no assimilation in saline. The ability of M. sodonensis to completely oxidize glucose and to grow on intermediates of glucose oxidation but not on glucose suggests that glucose may suppress or repress some reaction(s) necessary for growth, and that growth substrates either derepress or circumvent this block. Micrococcus sodonensis is an obligate aerobe that can grow on a biotin-containing synthetic medium with lactate, succinate, pyruvate, or acetate as the carbon and energy source. In the original description of the organism, the inability to produce acid or gas from carbohydrates was noted (1). Subsequent research (14) demonstrated that M. sodonensis does not grow when glucose or other carbohydrates are the sole source of carbon and energy. Recently, we observed, however, that the addition of glucose to a medium containing lactate as substrate increased the rate and amount of growth of M. sodonensis (Perry and Evans, Bacteriol. Proc., p. 77, 1965). This increase in rate of growth and total cell yield also occurred with other substrates. Experiments with nonproliferating cells indicated that glucose is readily oxidized by this organism without prior induction. This observation has been extended,

Section: Resultscontrasting

confidence: 56%

Oxidation and Assimilation of Carbohydrates by Micrococcus sodonensis

Perry

Evans

1966

“…In a duplicate flask in which 0.2 ml of 10% sulfuric acid was tipped in at the break point (time when marked break in 02 consumption was observed), 13.4 m,uc were present in the supernatant. This is in contrast to the marked loss in cellular C14 noted on acidification of B. megaterium suspensions (Clifton, 1963a). With glucose agar-grown cells of E. coli of the same suspension turbidity (1:10 dilution reading of 150 in Klett-Summerson colorimeter, green filter No.…”

Section: Resultsmentioning

confidence: 84%

“…In some tests, the cells were grown in nutrient broth plus 1% glucose. The methods employed were the same as reported in the accompanying paper for Bacillus megaterium (Clifton, 1963a).…”

Section: Methodsmentioning

confidence: 99%

INFLUENCE OF GROWTH MEDIUM ON ASSIMILATORY ACTIVITIES OF ESCHERICHIA COLI

Clifton

1963

Self Cite

Nutrient agargrown cells assimilate about 50% of the glucose added to washed suspensions (phosphate buffer, pH 7.2, 30 C), as indicated by 02 consumption or C"4-uptake from uniformly labeled glucose. Most of the nonassimilated glucose is oxidized, but a small portion remains in forms other than glucose in the suspension medium. Cells from glucose agar, however, assimilate only about 20 to 30% of the U-glucose and ferment a considerable portion of the remainder, the extent of each being determined in part at least by growth conditions. Evidence is presented that this behavior is the result of metabolic controls induced during growth. C14 from U-glucose appeared in all fractions of either agaror glucose agar-grown cells, the highest percentage being present in cellular matter insoluble in hot 5% trichloroacetic acid. Data on the distribution of C14 from 1-, 2-, and 6-glucose, and from acetate and pyruvate, are also presented.

“…A total of 15. 4 ,umoles of C02-C was produced; hence, 15.4 -8.5 = 6.9 ,umoles of endogenous C02-C. In the endogenous system, 9.0 ,umoles of CO2-C was produced during the 30-min test period.…”

Section: Resultsmentioning

confidence: 96%

Influence of Glutamic Acid on the Endogenous Respiration of Bacillus subtilis

Clifton

Cherry

1966

Self Cite

Influence of glutamic acid on the endogenous respiration of Bacillus subtilis. J. Bacteriol. 91:546-550. 1966.-Amino acids serve as the major initial endogenous substrate for Bacillus subtilis. The endogenous activity of freshly harvested washed cells is high and falls off rapidly with time of shaking at 30 C to lower but still significant levels. The rate of 02 consumption after the addition of glutamic acid also decreases as the cells age, but more slowly than noted for endogenous respiration. When cells were fed glutamate as soon as possible after harvesting, an apparent stimulation of endogenous respiration was noted. However, endogenous activity was inhibited if the cell suspensions were shaken for at least 1 hr before addition of the glutamate. Similar results were obtained with glycerol or glucose as exogenous substrates. Variation in rates of respiration with age of the cells, inherent instability of B. subtilis, and possible utilization of substances initially excreted by the cells appear to account for the variations noted regarding the influence of an exogenous substrate on endogenous respiration.