1887

Abstract

SUMMARY: Magnesium-limited mixed cultures, each containing two microbial species, were produced by exchange of small numbers of organisms between magnesium-limited chemostat cultures of and . The fate of each species in these mixed cultures was determined following cross-inoculation. Gram-negative organisms invariably outgrew the Gram-positive ones, but the ability of and to outgrow each other, or to outgrow the yeast, depended on the inoculum size. This dependence resulted from the presence of specific extracellular products in the Bacillus cultures which stimulated their growth and uptake of magnesium. The concentration of these extracellular growth-promoting substance(s) in magnesium-limited cultures of varied with population density. Thus, when the magnesium concentration in the medium was decreased from 0.9 to 0.15 μg./ml. (thereby causing the steady-state population density to be decreased to one-eightieth the initial value), could no longer maintain itself against proportionately low concentrations of . But addition of extracellular fluids from dense magnesium-limited cultures to magnesium-limited cultures enabled small numbers of the Bacillus now to outgrow the yeast. From these two observations it is concluded that magnesium assimilation by is more dependent on extracellular substance(s) than is magnesium assimilation by either or the Gram-negative organisms. Modification of the basic theory of microbial growth in a chemostat culture, to take account of product-stimulated substrate-assimilation, is suggested.

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/content/journal/micro/10.1099/00221287-52-2-309
1968-07-01
2022-05-27
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References

  1. Bail O. 1929; Ergebnisse experimenteller Populationsforschung.. Z. ImmunForsch 60:1
    [Google Scholar]
  2. Byers B. R., PoWell M. V., Lankford C. E. 1967; Iron-chelating hydroxamic acid (Schizo kinen) active in initiation of cell division in Bacillus megaterium . J. Bact 93:286
    [Google Scholar]
  3. Contois D. E. 1959; Kinetics of bacterial growth. Relationship between population density and specific growth rate of continuous cultures.. J. gen. Microbiol 21:40
    [Google Scholar]
  4. Dawes E. A., Ribbons D. W. 1964; Some aspects of the endogenous metabolism of bacteria.. Bact. Rev 28:126
    [Google Scholar]
  5. Demain A. L., Burg R. W., Hendlin D. 1965; Excretion and degradation of ribonucleic acid by Bacillus subtilis . J. Bact 89:640
    [Google Scholar]
  6. Herbert D., Elsworth R., Telling R. C. 1956; The continuous culture of bacteria; a theoretical and experimental study.. J. gen. Microbiol 14:601
    [Google Scholar]
  7. Jannasch H. W. 1962; Bacterial growth at low population densities.. Nature, Lond 196:496
    [Google Scholar]
  8. Jannasch H. W. 1963; Bacterial growth at low population densities (II).. Nature, Lond 197:1322
    [Google Scholar]
  9. Jannasch H. W. 1968; Enrichments of aquatic bacteria in continuous culture.. Arch, für Mikrobiol 59:165
    [Google Scholar]
  10. Meers J. L., Tempest D. W. 1968; Influence of extracellular products on the growth of mixed microbial populations in Mg2+-limited chemostat cultures.. J. gen. Microbiol 50:iv
    [Google Scholar]
  11. Monod J. 1950; La technique de culture continue; théorie et applications.. Annls Inst. Pasteur, Paris 79:390
    [Google Scholar]
  12. Postgate J. R., Hunter J. R. 1962; The survival of starved bacteria.. J. gen. Microbiol 29:233
    [Google Scholar]
  13. PoWell E. O. 1958; Criteria for the growth of contaminants and mutants in continuous culture.. J. gen. Microbiol 18:259
    [Google Scholar]
  14. PoWell E. O. 1965; Theory of the chemostat.. Lab. Practice 14:1145
    [Google Scholar]
  15. Strange R. E., Hunter J. R. 1967; Effect of magnesium on the survival of bacteria in aqueous suspension.. Microbial Physiology and Continuous Culture102 London: H.M.S.O.;
    [Google Scholar]
  16. Strange R. E., Dark F. A., Ness A. G. 1961; The survival of stationary phase cells of Aerobacter aerogenes stored in aqueous suspension.. J. gen. Microbiol 25:61
    [Google Scholar]
  17. Strange R. E., Wade H. E., Ness A. G. 1963; The catabolism of proteins and nucleic acids in starved Aerobacter aerogenes . Biochem. J 86:197
    [Google Scholar]
  18. Tempest D. W., Dicks J. W., Hunter J. R. 1966; The interrelationship between potassium, magnesium and phosphorus in potassium-limited chemostat cultures of Aerobacter aerogenes . J. gen. Microbiol 45:135
    [Google Scholar]
  19. Tempest D. W., Dicks J. W., Meers J. L. 1967; Magnesium-limited growth of Bacillus subtilis, in pure and mixed cultures, in a chemostat.. J. gen. Microbiol 49:139
    [Google Scholar]
  20. Tempest D. W., Hunter J. R., Sykes J. 1965; Magnesium-limited growth of Aerobacter aerogenes in a chemostat.. J. gen. Microbiol 39:355
    [Google Scholar]
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