TABLE 3.
Intracellular levels of glycogen and trehalose in unstarved, carbon-starved, or nitrogen-starved cells,f with a statistical analysis using Student's two-sample t testg
| Growth condition (pH) | Acid present | Glycogen (%)
|
Trehalosed (%) | ||
|---|---|---|---|---|---|
| Unstarved | C starved | N starved | |||
| Carbon limited (5) | 0a | 13 ± 0.2(A)(D) | 1.3 ± 0.3(B) | 21 ± 0.3(C)(D) | 0.6 ± 0.2 |
| L90b | 13 ± 1.3(A)(D) | 1.5 ± 0.3(B) | 19 ± 1.8(C)(D) | 2.8 ± 0.5 | |
| L280b | 8.3 ± 0.2(A)(D) | 1.6 ± 0.0(B) | 16 ± 1.6(C)(D) | 3.2 ± 0.5 | |
| B5c | 1.6 ± 0.1 | 0.1 ± 0.0 | 15 ± 0.8 | 3.5 ± 0.0 | |
| Carbon limited (3.25) | 0a | 8.9 ± 0.1(A)(E) | 1.9 ± 0.0(B)(E) | 17 ± 0.8(C) | 3.2 ± 0.9 |
| L90b | 4.5 ± 0.2(A)(E) | 0.6 ± 0.0(B)(E) | 19 ± 0.1(C) | 4.6 ± 0.9 | |
| L280b | 2.9 ± 0.0(A)(E) | 0.9 ± 0.1(B)(E) | 18 ± 0.0(C) | 4.5 ± 0.9 | |
| Nitrogen limited (5) | 0a | 3.6 ± 0.2(F) | 0.9 ± 0.2(B)(F) | 10 ± 0.2 | 3.9 ± 0.6 |
| L90b | 1.3 ± 0.1(F) | NDe(B)(F) | 8.7 ± 0.0 | 2.8 ± 0.1 | |
| L280b | 1.2 ± 0.2(F) | NDe(B)(F) | 10 ± 1.2 | 6.1 ± 4.3 | |
| B5c | 1.7 ± 0.1 | 0.2 ± 0.0 | 12 ± 0.4 | 3.7 ± 0.0 | |
| Nitrogen limited (3.25) | 0a | 1.8 ± 0.1(G) | NDe(G) | 10 ± 0.6 | 3.5 ± 0.6 |
| L90b | 1.2 ± 0.0(G) | NDe(G) | 7.3 ± 1.7 | 1.7 ± 0.1 | |
| L280b | 0.5 ± 0.3(G) | NDe(G) | 9.6 ± 1.0 | 3.3 ± 0.2 | |
No weak acid present.
Lactic acid present at a concentration of 90 or 280 mM.
Benzoic acid present at a concentration of 5 mM.
The concentration of trehalose was below the estimated limit for determination for unstarved cells and for carbon-starved cells; thus, only data for N-starved cells are shown.
The concentration was below the estimated limit for determination.
Deviations are given as standard deviation calculated from two separate starvation cultures.
Student's two-sample t test (P > 0.01; df = 4) was used for a statistical analysis of the data on glycogen. Data for cells grown in presence of benzoic acid were excluded. The influence of growth conditions on glycogen content of unstarved, carbon-starved, or nitrogen-starved cells was analyzed. The respective group of values obtained from cells grown under carbon limitation at pH 5 irrespective of lactic acid concentration, i.e., unstarved (A), starved for carbon (B), or nitrogen (C), respectively, was used as reference when comparing with data groups from other growth conditions in the same column. The influence of carbon or nitrogen starvation on glycogen content of cells grown at the same growth conditions was also analyzed. The respective group of data obtained for unstarved cells under the four growth conditions—carbon limitation at pH 5 (D), at carbon limitation at pH 3.25 (E), at nitrogen limitation at pH 5 (F), or nitrogen limitation at pH 3.25 (G), irrespective of weak acid concentration—was used as the reference group. The reference group was compared with each of the two groups of data for carbon-or nitrogen-starved cells grown under the same growth conditions in the same row.