Previous Article | Next Article 
Appl Environ Microbiol, January 1998, p. 273-278, Vol. 64, No. 1
Department of Microbiology and Cell Science,
University of Florida, Gainesville, Florida 32611-0700
Received 11 August 1997/Accepted 23 October 1997
Penicillium fellutanum is osmotolerant and xerotolerant
when cultured in a low-phosphate medium containing 3 M NaCl. Glycerol and erythritol accumulated in cultures with NaCl concentrations up to 2 M; glycerol was the only detectable polyol in cultures containing 3 M
NaCl. In cultures with 3 M NaCl, the intracellular levels of glycine
betaine and choline-O-sulfate were 22- and 2.6-fold greater
(70 and 46 mM), respectively, than those of cultures without added
NaCl. The levels of glycine betaine and glycerol decreased in mycelia
transferred from a medium containing 3 M NaCl into a fresh medium
without added NaCl. NaCl at 3 M inhibited mycelial mass accumulation;
this inhibition was partially corrected by supplementation of cultures
with glycine betaine (2 mM) or choline-O-sulfate (10 mM).
The presence of exogenous choline chloride (2 mM) in plate cultures
protected the cells from stress from 3 M NaCl. The data suggest that
glycine betaine and choline-O-sulfate are secondary
osmoprotectants which are effective at the point that the cell is
incapable of synthesizing more glycerol.
Cellular adaptation to extreme
environmental conditions, such as high-saline environments, is a
fundamental biological process needed for survival and growth of
organisms (14, 25, 43). Osmotic stress is caused by large
concentrations of either salts or nonionic solutes in the surrounding
medium; this results in dehydration of cells (7, 30, 46,
50). Salinity is a major limiting factor in agricultural
productivity (30) and is of concern in the food and
medicinal industries (8, 17, 24, 28, 40, 42, 43, 48).
Fungi, including yeasts, are well known for their ability to adapt to
environments of high osmolarity by intracellular accumulation of
species of neutral, low-molecular-weight compounds which maintain positive turgor pressure (7, 11, 12). Fungal cells
synthesize polyols even without osmotic stress and respond to osmotic
stress by accumulation of predominantly polyols (7, 21).
These compatible solutes can accumulate up to molar concentrations
without greatly interfering with the normal functions of intracellular
enzymes; these solutes may protect enzymes and other cellular
components from high salt concentrations (4, 41, 49, 50).
The known osmoresponsive compatible solutes used by fungi are mainly
polyhydroxy alcohols, trehalose, and K+. Glycerol is the
predominant osmoprotectant (1, 3, 5, 7, 16, 19, 26, 31).
Penicillium and Aspergillus species tested
accumulate glycerol as a major, and erythritol as a minor, osmoregulatory solute (2, 16, 22, 23).
We reported that glycine betaine (GB) and choline-O-sulfate
(COS) accumulate inside Penicillium fellutanum cultured in a
low-phosphate medium (39). Phosphocholine of extracellular
peptidophosphogalactomannan (pPxGM [where
x is the number of phosphodiester residues]) is a precursor
of these two intracellular choline derivatives. Experiments were
performed to determine if these intracellular choline derivatives are
involved in adaptation to osmotic stress in P. fellutanum.
This paper reports that intracellular GB, COS, and exogenous choline
are involved in osmoprotection of P. fellutanum under
low-phosphate and high-osmolarity conditions.
Chemicals and strain.
Sodium
(trimethylsilane)-1-propanesulfonate (TSP) was obtained from Wilmad
Glass Co., Buena, N.J.
L-[methyl-13C]methionine and
deuterium oxide (D2O) were purchased from Sigma, St. Louis,
Mo. All other chemicals were reagent grade and were obtained from
commercial sources. P. fellutanum (formerly
Penicillium charlesii G. Smith [NRRL 1887]), was a gift
from Kenneth Raper, Department of Bacteriology, University of
Wisconsin, Madison.
Medium and growth conditions.
Conidiospore suspensions were
prepared as described previously (39), stored at 4°C, and
used for routine inoculation. For 13C nuclear magnetic
resonance (NMR) analysis of intracellular solutes, cultures were grown
in 200 ml of low-phosphate standard growth (LPSG) medium containing 2 mM phosphate in 500-ml notched wide-mouth Erlenmeyer flasks at 22°C
under constant light and shaking at 40 rpm on a New Brunswick model
G-10 shaker.
L-[methyl-13C]methionine (50 mg)
was added to each culture flask 30 h after inoculation.
L-[methyl-13C]methionine was
dissolved in double-distilled water (ddH2O) and passed
through a sterile 0.22-µm-pore-size membrane filter (Millipore). The
composition of LPSG medium is described elsewhere (47).
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Choline Derivatives Involved in Osmotolerance of
Penicillium fellutanum
and
ABSTRACT
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
INTRODUCTION
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
MATERIALS AND METHODS
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
Preparation of extracts of mycelium. Mycelium was separated from the culture medium by filtration in vacuo on either a C- or M-type sintered glass filter, followed by washing with ddH2O containing the same salt concentration as that of the parent culture to avoid any possible loss of intracellular solutes during washing of harvested mycelium. Throughout this study, 80% ethanol extraction was performed as described previously (39).
13C NMR analysis of intracellular solute pools. To increase the sensitivity of the methyl amine-containing intracellular solutes to 13C NMR spectroscopy, cultures were enriched with 99 atom% L-[methyl-13C]methionine. 13C from L-[methyl-13C]methionine incorporated in vivo into methyl groups of intracellular choline derivatives was determined by proton-decoupled 13C NMR analysis with an NT-300 spectrometer with a 7-T Oxford magnet operating in the pulsed Fourier transform mode. For quantification of intracellular solutes by 13C NMR spectrometry, cultures were grown without added L-[methyl-13C]methionine. P. fellutanum was grown in 200 ml of LPSG medium that contained 20 mM NaCl. Sterile, solid NaCl (0.5, 1.0, 2.0, or 3.0 M) was added directly to each 200 ml of culture 72 h after inoculation. The mycelium was harvested on day 8. Four milliliters of each extract of mycelium was subjected to 13C NMR analysis with the addition of 0.5 ml of D2O and 0.51% of sodium TSP as an internal reference. Proton-decoupled 13C NMR spectra were recorded at 75 MHz as described previously (39). Data acquisition parameters were as follows: spectral width, 10,000 Hz; pulse width, 28 µs; acquisition time, 409.6 ms; spectrometer frequency, 75.457 MHz; number of acquisitions, 1,000; temperature, 10°C.
Osmotic downshift. To monitor the fate of intracellular solutes produced in the presence of 3 M NaCl in LPSG medium, the mycelium was initially cultured with L-[methyl-13C]methionine as described above. The mycelium was harvested on day 8 and transferred aseptically to a fresh LPSG medium without added NaCl and L-[methyl-13C]methionine. As a control, mycelium was transferred separately to a fresh medium containing 3 M NaCl. Each mycelium was harvested 3 days after transfer and extracted with 80% ethanol, and the water-soluble portions of extracts were analyzed by 13C NMR spectrometry.
Identification of COS and GB. Identification of intracellular GB and COS was performed by proton-decoupled 13C NMR spectrometry as described previously (39).
Identification of intracellular polyols. The identification of polyhydroxy alcohols in the intracellular solute pools was performed by 13C NMR analysis and confirmed by paper chromatography. Ten microliters of each cell extract obtained from the cultures treated with NaCl (final concentration, 0.5, 1.0, 2.0, or 3.0 M) was spotted onto Whatman no. 3 paper. Lanes containing 10 µl of glycerol and erythritol (100 mM each) served as references. The chromatogram was developed in a descending manner with n-butanol-pyridine-ddH2O (6:4:3, vol/vol/vol) for 11 h at room temperature. The chromatogram was then visualized after treatment with an aqueous solution of 2 ml of 40% AgNO3 in 80 ml of acetone. After air drying, the chromatogram was treated with 0.2 M Na2S2O3 and then air dried in a hood.
Salt stress and influence of exogenous GB chloride, COS, or choline chloride. P. fellutanum was cultured initially in LPSG medium (40 ml per flask). Either GB chloride (final concentration, 2 mM) or COS (final concentration, 10 mM) was added to the cultures 30 min before the addition of NaCl (3 M) at 60 h. GB chloride and COS were dissolved in ddH2O and added to the culture through a sterile 0.22-µm-pore-size membrane filter (Millipore). Growth was determined by measuring the mycelial dry weight (39). At selected intervals, the mycelium was recovered by filtration in vacuo on preweighed Whatman no. 1 paper filters supported by sintered glass and then dried at 100°C for 10 h.
The effect of exogenously added choline was examined by measuring the radial growth of the colonies on the surface of plates of C-source-limiting LPSG medium supplemented with 3 M NaCl. Choline chloride was dissolved in ddH2O and filter sterilized as described above and added (final concentration, 2 mM) to the agar medium before it became solidified. To decrease the accumulation of polyols and stimulate the accumulation of other osmoregulatory compatible solutes such as choline derivatives, only 1/10 of the C source (glucose) was used for these culture plates. The spore suspension was inoculated as a single spot with a diameter of 2.7 cm on the surface of agar plates containing 2 mM choline chloride. The diameter of the circular colonies was measured daily for 29 days.Measurement of intracellular choline derivatives. The amounts of intracellular GB and COS were determined by 13C NMR spectrometry with sodium TSP as a reference (39). For this purpose, the cultures were not enriched with L-[methyl-13C]methionine. The intensities of 13C-methyl signals of 13C NMR spectra of the mycelium extracts were integrated by using Felix for Windows 1.02 software (Molecular Simulations Inc.), and the integrated values were compared with that of sodium TSP.
| |
RESULTS |
|---|
|
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
|
|---|
Effect of osmotic upshock and downshift on intracellular choline derivatives in P. fellutanum. Cultures of P. fellutanum were enriched with L-[methyl-13C]methionine and NaCl at concentrations ranging from 0.5 to 3.0 M as described in Materials and Methods. The control contained no added NaCl. No major differences in the patterns and intensities of 13C NMR signals identified as COS1 and GB1 (39) were observed between cultures derived from mycelium intracellular pools in control medium lacking added NaCl (Fig. 1A) and those containing added 0.5 M (Fig. 1B) or 1.0 M (Fig. 1C) NaCl. [The signal at 56.76 ppm (designated COS1) represents -N+-(13CH3)3 of COS, and that at 56.23 ppm (designated GB1) represents -N+-(13CH3)3 of GB. The two signals upfield at 54.99 and 48.82 ppm were not of concern because they did not change intensity with increasing concentrations of NaCl.] The most prominent intracellular N-methyl solutes in P. fellutanum, grown for 8 days in LPSG medium with 3 M NaCl, were COS and GB (Fig. 1E). These results suggest that the level of GB is especially sensitive to high osmolarity.
|
|
|
Glycerol and erythritol as major osmoresponsive polyols in P. fellutanum. The two signals (designated G and E in Fig. 1) are those of primary (chemical shift, 65.47 ppm) and secondary (74.95 ppm) alcohol carbons of glycerol and erythritol. Glycerol and erythritol were identified by 13C NMR spectroscopy and paper chromatography; the chemical shifts of these two signals exactly matched those of C-1 and C-3 (CH2OH) and C-2 (CHOH) of commercial glycerol and C-1 and C-4 (CH2OH) and C-2 and C-3 (CHOH) of commercial erythritol.
The mycelium grown without added NaCl, the control, contained mainly erythritol and a negligible amount of glycerol as observed from the ratio of the intensity of the signal at 65.47 to that of the signal at 74.95 ppm (Fig. 1A); paper chromatography (Fig. 3, lane 3) also showed erythritol as the major polyol in the mycelium grown without added NaCl. As the concentration of NaCl was increased to 3 M (Fig. 1A to E), the ratio of signal intensities at 65.47 and 74.95 ppm significantly increased, indicating that the level of glycerol gradually increased. The paper chromatogram (Fig. 3) showed that in mycelium grown in LPSG medium without added NaCl (Fig. 3, lane 3), i.e., the control, or supplemented with 0.5, 1.0, or 2.0 M NaCl (lanes 4 to 6, respectively), the level of erythritol increased with increasing concentrations of NaCl (up to 2 M) in the culture medium. The level of glycerol also increased with increasing concentrations of NaCl (lanes 3 to 7), although the mycelium grown with 0.5, 1, or 2 M NaCl (lanes 4 to 6, respectively) contained slightly more erythritol than glycerol. In contrast, in the mycelium from cultures grown with 3 M NaCl, glycerol was the major polyol detected (Fig. 1E); there was no significant spot equivalent to erythritol on the chromatogram (Fig. 3, lane 7). Both glycerol and erythritol were major polyols in mycelium cultured with 2 M NaCl (Fig. 1D and Fig. 3, lane 6).
|
Osmoprotection of mycelium by exogenous GB, COS, or choline. To provide evidence of the ability of exogenous GB chloride or COS to protect the mycelium against osmotic stress, P. fellutanum was cultured in LPSG medium containing 3 M NaCl and with, or without, added GB chloride (2 mM) or COS (10 mM) (Table 2). Addition of 3 M NaCl to the cultures 60 h after inoculation caused a 33% decrease in mycelium dry weight within 12 h (on day 3); the dry weights of the cultures supplemented with either GB chloride (2 mM) or COS (10 mM) were unchanged or increased 25%, respectively. The dry weights of the mycelium in cultures with either GB or COS added were greater than those of control cultures at days 4, 6, and 8. After the initial stage of repressed growth, during the initial stage of salt stress, a parallel increase in dry weight occurred.
|
|
| |
DISCUSSION |
|---|
|
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
|
|---|
Osmoregulatory compatible solutes have been identified and quantified by 13C NMR spectroscopy in bacteria (10, 32, 34), marine mollusc (36, 38), and fungi, including yeasts (6, 7, 10, 37, 44, 45). Polyhydroxy alcohols, such as glycerol, arabinitol, and erythritol, are the most predominant compatible solutes in fungi (7). The presence of GB and COS as osmoprotectants has not been reported for genera of Penicillium or Aspergillus.
It has been shown that P. fellutanum mycelium cultured in a medium containing 20 mM phosphate contained no detectable GB and 1.5-fold less COS than mycelium cultured in medium containing 2 mM phosphate (39). In contrast, modification of the high-phosphate medium with 3 M NaCl resulted in a large increase in glycerol in the mycelium but no significant increase in levels of COS and GB (data not shown).
The results of the current investigation suggest that intracellular GB and COS, as well as glycerol and erythritol, are important osmoregulators in P. fellutanum grown under low-phosphate and high-osmolarity conditions. GB, COS, and erythritol were found in the mycelium grown in low-phosphate medium with no NaCl supplementation. As the concentration of NaCl in the LPSG medium was increased from 2 to 3 M, GB and COS combined concentrations increased from approximately 20 mM to greater than 100 mM, assuming that 80% of the cell mass was water (Table 1). These data suggest that GB and COS are compatible solutes in P. fellutanum.
Nonspecific phosphocholine:phosphocholine hydrolase in LPSG cultures of P. fellutanum catalyzes the release of phosphocholine from its diester attachment as a component of extracellular pPxGM (39, 47). Thus, the choline moiety from released phosphocholine is the precursor of GB and COS that accumulates inside the mycelium as GB and COS (39). Utilization of GB and COS as osmoprotectants may thus be confined to those mycelia cultured in low-phosphate and high-osmolarity media and may be dependent on the presence of significant activity of extracellular pPxGM phosphocholine:phosphocholine hydrolase, which provides excess choline for its immediate needs compared with that for phosphate. This suggests a relationship between phosphate concentration and osmotic stress regulons in P. fellutanum. In recent reports, interesting connections are beginning to be revealed between the phosphate and osmotic stress regulons in bacteria (27). Whether the extracellular phosphocholine-containing polysaccharide pPxGM is actively involved in osmoprotection of this fungus and this process is governed by both phosphate and osmotic stress regulons remain open.
Furthermore, the data also suggest that the relative abundance of the C source (glucose) in fresh medium also influences which osmoprotectants are formed. For instance, the use of fresh LPSG medium containing 3 M NaCl, which contains 277 mM glucose, provided carbon for synthesis of additional glycerol (Fig. 2C). Thus, an additional quantity of glycerol precursor eliminated the need for GB and/or COS under continuing 3 M NaCl stress, and no further accumulation of GB and COS occurred.
The increase in the level of GB was about 10-fold greater than that of COS upon addition of 3 M NaCl to the LPSG culture medium (Table 1). This suggests that P. fellutanum preferentially uses GB rather than COS for protection against high osmotic stress. COS is known as a storage form of sulfate in Penicillium and Aspergillus spp. (33); this may account for the high level (17 mM) in cultures in LPSG medium lacking added NaCl. Although the total GB concentration in mycelium grown in LPSG medium that contained 3 M NaCl was nearly twice that of COS, accumulation of COS undoubtedly depends on the presence of adequate sulfate in the culture medium (unpublished data).
It is generally observed that Penicillium species survive in environments containing high concentrations of carbohydrates, protein degradation products, and salts. The data presented here show that P. fellutanum survives and grows at a reduced rate in an environment containing 3 M NaCl. Day-8 cultures have a limiting concentration of glucose; this limits the quantity of glycerol that it can generate for its osmoprotection. Products of proteolytic digestion will provide, in P. fellutanum, carbon skeletons for biosynthesis of choline, a precursor of GB and COS, in a natural environment with a limiting concentration of carbohydrate; however, the possibility that GB and COS are derived mostly from phosphocholine diester of pPxGM synthesized by N-methyl transfer to phosphoethanolamine phosphodiester of pPGM has not been eliminated. It has been shown that methyl groups derived from L-[methyl-13C]methionine (39) or from [C2-13C]glycine become incorporated into both COS and GB. Amino acids, betaines, and choline derivatives are known major osmoprotectants in bacteria (9, 13, 15, 18, 27, 29, 35), algae (8), plants (46), and animals (51). COS is an osmoregulator in marine algae, a few bacteria, some marine fungi, and halophytic plants (8, 20, 46). In Penicillium and Aspergillus species, choline and sulfate are stored as COS (33); however, the role of COS as an osmoprotectant in these species has not been reported.
| |
ACKNOWLEDGMENTS |
|---|
This work was supported by the Florida Agricultural Experiment Station and by a Research Project Enhancement Award from the Office of the Dean for Research, Institute of Food and Agricultural Sciences, University of Florida, Gainesville.
We thank Marian L. Buszko for assistance with NMR techniques and K. T. Shanmugam and R. R. Schmidt for helpful suggestions.
| |
FOOTNOTES |
|---|
* Corresponding author. Mailing address: Department of Microbiology and Cell Science, University of Florida, Bldg. 981, Gainesville, FL 32611-0700. Phone: (352) 392-0384. Fax: (352) 392-5922. E-mail: john{at}micro.ifas.ufl.edu.
Journal Series No. RO5664 of the Florida Agricultural Experiment
Station.
Present address: Department of Biology, Johns Hopkins University,
Baltimore, MD 21218-2699.
| |
REFERENCES |
|---|
|
Top
Abstract
Introduction
Materials & Methods
Results
Discussion
References
|
|---|
| 1. | Adler, L., and L. Gustafsson. 1980. Polyhydric alcohol production and intracellular amino acid pool in relation to halotolerance of the yeast Debaryomyces hansenii. Arch. Microbiol. 124:123-130. |
| 2. | Adler, L., A. Pedersen, and I. Tunblad-Johansson. 1982. Polyol accumulation by two filamentous fungi grown at different concentrations of NaCl. Physiol. Plant 56:139-142. |
| 3. | Andre, L., A. Nilsson, and L. Adler. 1988. The role of glycerol in osmotolerance of the yeast Debaryomyces hansenii. J. Gen. Microbiol. 134:669-677. |
| 4. | Arakawa, T., and S. N. Timasheff. 1985. The stabilization of proteins by osmolytes. Biophys. J. 47:411-414[Medline]. |
| 5. |
Beever, R. E., and E. P. Laracy.
1986.
Osmotic adjustment in the filamentous fungus Aspergillus nidulans.
J. Bacteriol.
168:1358-1365 |
| 6. | Bellinger, Y., and F. Larher. 1988. A 13C comparative nuclear magnetic resonance study of organic solute production and excretion by the yeasts Hansenula anomala and Saccharomyces cerevisiae in saline media. Can. J. Microbiol. 34:605-612[Medline]. |
| 7. | Bloomberg, A., and A. Adler. 1992. Physiology of osmotolerance in fungi. Adv. Microb. Physiol. 33:144-212. |
| 8. | Blunden, G., and S. M. Gordon. 1986. Betaines and their sulphonio analogues in marine algae. Prog. Physiol. Res. 4:39-80. |
| 9. |
Boch, J.,
B. Kempf, and E. Bremer.
1994.
Osmoregulation in Bacillus subtilis: synthesis of the osmoprotectant glycine betaine from exogenously provided choline.
J. Bacteriol.
176:5364-5371 |
| 10. |
Borowitzka, L. J.,
S. Demmerle,
M. A. Mackay, and R. S. Norton.
1980.
Carbon-13 nuclear magnetic resonance study of osmoregulation in a blue-green alga.
Science
210:650-651 |
| 11. | Brown, A. D. 1978. Compatible solutes and extreme water stress in eukaryotic micro-organisms. Adv. Microb. Physiol. 17:181-241[Medline]. |
| 12. |
Brown, A. D., and J. R. Simpson.
1972.
Water relations of sugar-tolerant yeasts: the role of intracellular polyols.
J. Gen. Microbiol.
72:589-591 |
| 13. |
Csonka, L. N.
1989.
Physiological and genetic responses of bacteria to osmotic stress.
Microbiol. Rev.
53:121-147 |
| 14. | Da Costa, M. S., J. C. Duarte, and R. A. D. Williams (ed.). 1989. . Microbiology of extreme environments and its potential for biotechnology. Elsevier Science Publishers Ltd., Essex, England. |
| 15. | Gadd, G. M., J. A. Chudek, R. Foster, and R. H. Reed. 1984. The osmotic response of Penicillium ochro-chloron: changes in internal solute levels in response to copper and salt stress. J. Gen. Microbiol. 130:1969-1975. |
| 16. | Galinski, E. A. 1995. Osmoadaptation in bacteria. Adv. Microb. Physiol. 37:273-328. |
| 17. |
Glaasker, E.,
W. N. Konigs, and B. Poolman.
1996.
Osmotic regulation of intracellular solute pools in Lactobacillus plantarum.
J. Bacteriol.
178:575-582 |
| 18. |
Graham, J. E., and B. J. Wilkinson.
1992.
Staphylococcus aureus osmoregulation: roles for choline, glycine betaine, proline, and taurine.
J. Bacteriol.
174:2711-2716 |
| 19. | Gustafsson, L., and B. Norkrans. 1976. On the mechanisms of salt tolerance. Production of glycerol and heat during the growth of Debaryomyces hansenii. Arch. Microbiol. 110:177-183[Medline]. |
| 20. | Hanson, A. D., and D. A. Gage. 1991. Identification and determination by fast atom bombardment mass spectrometry of the compatible solute choline-O-sulfate in Limonium species and other halophytes. Aust. J. Plant Physiol. 18:317-327. |
| 21. | Harris, R. F. 1981. Effect of water potential on microbial growth and activity, p. 23-95. In J. F. Parr, W. R. Gardner, and L. F. Elliot (ed.), Water potential relations in soil microbiology, vol. 9. Soil Science Society of America, Madison, Wis. |
| 22. | Hocking, A. D. 1986. Effect of water activity and culture age on the glycerol accumulation of five fungi. J. Gen. Microbiol. 132:269-275. |
| 23. | Hocking, A. D., and R. S. Norton. 1983. Natural-abundance 13C nuclear magnetic resonance studies on the internal solutes of xerophilic fungi. J. Gen. Microbiol. 129:2915-2925. |
| 24. | Hollaender, A., J. C. Aller, E. Epstein, A. San Pietro, and O. R. Zaborsky (ed.). 1979. . The biosaline concept: an approach to the utilization of under-exploited resources. Plenum Press, New York, N.Y. |
| 25. | Ingraham, J. 1987. Effect of temperature, pH, water activity, and pressure on growth, p. 1543-1554. In F. C. Neidhardt, J. L. Ingraham, K. B. Low, B. Magasanik, M. Schaechter, and H. E. Umbarger (ed.), Escherichia coli and Salmonella typhimurium: cellular and molecular biology. American Society for Microbiology, Washington, D.C. |
| 26. | Jennings, D. H. 1984. Polyol metabolism in fungi. Adv. Microb. Physiol. 25:149-193[Medline]. |
| 27. |
Kaenjak, A.,
J. E. Graham, and B. J. Wilkinson.
1993.
Choline transport activity in Staphylococcus aureus induced by osmotic stress and low phosphate concentrations.
J. Bacteriol.
175:2400-2406 |
| 28. |
Ko, R.,
L. T. Smith, and G. M. Smith.
1994.
Glycine betaine confers enhanced osmotolerance and cryotolerance on Listeria monocytogenes.
J. Bacteriol.
176:426-431 |
| 29. |
Landfald, B., and A. R. Strom.
1986.
Choline-glycine betaine pathway confers a high level of osmotic tolerance in Escherichia coli.
J. Bacteriol.
165:849-855 |
| 30. |
Le Rudulier, D.,
A. R. Strom,
A. M. Dandekar,
L. T. Smith, and R. C. Valentine.
1984.
Molecular biology of osmoregulation.
Science
224:1064-1068 |
| 31. | Luard, E. J. 1982. Accumulation of intracellular solutes by two filamentous fungi in response to growth at low steady state osmotic potential. J. Gen. Microbiol. 128:2563-2574. |
| 32. | Mackay, M. A., R. S. Norton, and L. J. Borowitzka. 1983. Marine blue-green algae have a unique osmoregulatory system. Mar. Biol. 73:301-307. |
| 33. | Markham, P., G. D. Robson, B. W. Bainbridge, and A. P. J. Trinci. 1993. Choline: its role in the growth of filamentous fungi and the regulation of mycelial morphology. FEMS Microbiol. Rev. 104:287-300. |
| 34. |
Martins, L. O.,
L. S. Carreto,
M. S. Da Costa, and H. Santos.
1996.
New compatible solutes related to di-myo-inositol-phosphate in members of the order Thermotogales.
J. Bacteriol.
178:5644-5651 |
| 35. | Measures, J. C. 1975. Role of amino acids in osmoregulation of non-halophilic bacteria. Nature (London) 257:398-400[Medline]. |
| 36. | Norton, R. S. 1979. Identification of mollusc metabolites by natural abundance 13C-NMR studies of whole tissue and tissue homogenates. Comp. Biochem. Physiol. B 63:67-72. |
| 37. | Norton, R. S. 1980. 13C-NMR studies of intact cells and tissue. Bull. Magnetic Resonance 3:29-48. |
| 38. | Norton, R. S., and P. de Rome. 1980. 13C-NMR study of osmoregulatory metabolites in the marine mollusc Tapes watlingi. Experientia 36:522-532. |
| 39. |
Park, Y.-I.,
M. L. Buszko, and J. E. Gander.
1997.
Utilization of phosphocholine from extracellular complex polysaccharide as a source of cytoplasmic choline derivatives in Penicillium fellutanum.
J. Bacteriol.
179:1186-1192 |
| 40. | Pitt, J. I. 1975. Xerophilic fungi and the spoilage of foods of plant origin, p. 273-307. In R. B. Duckworth (ed.), Water relations of foods. Academic Press Ltd., London, United Kingdom. |
| 41. | Pollard, R., and R. G. Wyn Jones. 1979. Enzyme activities in concentrated solutions of glycine betaine and other solutes. Planta 144:291-298. |
| 42. |
Potts, M.
1994.
Desiccation tolerance of prokaryotes.
Microbiol. Rev.
58:755-805 |
| 43. | Rains, D. W., R. C. Valentine, and A. Hollanender (ed.). 1980. . Genetic engineering of osmoregulation: impact on plant productivity for food, chemicals and energy. Plenum Press, New York, N.Y. |
| 44. |
Reed, R. H.,
J. A. Chudek,
R. Roster, and G. M. Gadd.
1987.
Osmotic significance of glycerol accumulation in exponentially growing yeasts.
Appl. Environ. Microbiol.
53:2119-2123 |
| 45. | Reed, R. H., J. A. Chudek, R. Foster, and W. D. P. Stewart. 1984. Osmotic adjustment in cyanobacteria from hypersaline environments. Arch. Microbiol. 138:333-337. |
| 46. | Rhodes, D., and A. D. Hanson. 1993. Quaternary ammonium and tertiary sulfonium compounds in higher plants. Annu. Rev. Plant Mol. Biol. 44:357-384. |
| 47. | Salt, S. D., and J. E. Gander. 1985. Variations in phosphoryl substituents in extracellular peptidophosphogalactomannans from Penicillium charlesii G. Smith. Exp. Mycol. 9:9-19. |
| 48. | Smith, L. T. 1996. Role of osmolytes in adaptation of osmotically stressed Listeria monocytogenes grown in liquid media and on processed meat surfaces. Appl. Environ. Microbiol. 62:3088-3093[Abstract]. |
| 49. | Wyn Jones, R. G. 1984. Phytochemical aspects of osmotic adaptation. Recent Adv. Phytochem. 18:55-78. |
| 50. |
Yancey, P.,
M. Clark,
S. Hand,
R. Bowlus, and G. Somero.
1982.
Living with water stress: evolution of osmolyte systems.
Science
217:1214-1222 |
| 51. |
Zablocki, K.,
S. P. F. Miller,
A. Garcia-Perez, and M. B. Burg.
1991.
Accumulation of glycerophosphocholine (GPC) by renal cells: osmotic regulation of GPC:choline phosphodiesterase.
Proc. Natl. Acad. Sci. USA
88:7820-7824 |
Appl Environ Microbiol, January 1998, p. 273-278, Vol. 64, No. 1
0099-2240/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Plummer, R., Bodkin, J., Power, D., Pantarat, N., Bubb, W. A., Kuchel, P. W., Sorrell, T. C.
(2007). Effect of Caspofungin on Metabolite Profiles of Aspergillus Species Determined by Nuclear Magnetic Resonance Spectroscopy. Antimicrob. Agents Chemother.
51: 4077-4084
[Abstract] [Full Text] -
Tuekam, B. A., Park, Y.-I., Unkefer, C. J., Gander, J. E.
(2001). Relationship of Exo-{beta}-D-Galactofuranosidase Kinetic Parameters to the Number of Phosphodiesters in Penicillium fellutanum Peptidophosphogalactomannan: Enzyme Purification and Kinetics of Glycopeptide and Galactofuran Chain Hydrolysis. Appl. Environ. Microbiol.
67: 4648-4656
[Abstract] [Full Text] -
Park, Y.-I., Bonetti, S. J., Gander, J. E.
(2000). Influence of Osmotic and Nutritional Stress on Physiology of Penicillium fellutanum in Removal of Phosphocholine and Modification of Phospho-1-O-[N-Peptidyl-(2-Aminoethanol)] Phosphodiesters of Peptidophosphogalactomannan Species. Appl. Environ. Microbiol.
66: 832-835
[Abstract] [Full Text] -
Park, Y.-I., Buszko, M. L., Gander, J. E.
(1999). Glycine Betaine: Reserve Form of Choline in Penicillium fellutanum in Low-Sulfate Medium. Appl. Environ. Microbiol.
65: 1340-1342
[Abstract] [Full Text] -
Nau-Wagner, G., Boch, J., Le Good, J. A., Bremer, E.
(1999). High-Affinity Transport of Choline-O-Sulfate and Its Use as a Compatible Solute in Bacillus subtilis. Appl. Environ. Microbiol.
65: 560-568
[Abstract] [Full Text]
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»