Development and activity of the association of the sulphur cycle bacteria, represented by Thiobacillus thioparus and Desulfovibrio sp., were followed in chernozem soil continuously supplemented with sodium thiosulphate. The technique of heterocontinuous cultivation made it possible (i) to determine changes in the individual components of microflora involved in successive metabolic steps, their time and space sequence, (ii) to follow changes in the transformations of substrate and formation of metabolic products, and (iii) to reach a steady state in the system. A possible use of this approach for the evaluation of the effect of ecological factors, for modelling microbiological processes of the sulphur cycle, for the investigation of trophic relationships among microorganisms in natural and artificial association and for the evaluation of the geochemical activity of sulphur bacteria is discussed.

• MeSH
• Biotransformation MeSH
• Desulfovibrio growth & development   metabolism   MeSH
• Ecology MeSH
• Hydrogen-Ion Concentration MeSH
• Soil Microbiology * MeSH
• Sulfates metabolism   MeSH
• Thiobacillus growth & development   metabolism   MeSH
• Thiosulfates metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Sulfates MeSH
• sodium thiosulfate MeSH Browser
• Thiosulfates MeSH

• MeSH
• Nitrites metabolism   MeSH
• Culture Techniques MeSH
• Quaternary Ammonium Compounds metabolism   MeSH
• Nitrobacter growth & development   metabolism   MeSH
• Soil Microbiology * MeSH
• Solutions MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Nitrites MeSH
• Quaternary Ammonium Compounds MeSH
• Solutions MeSH

A soil naturally containing montmorillonite (M) was amended with 10% M and sequentially perfused with glyeme, with fresh glyeme being added every 16--17d after nitrification of the previously added glycine-nitrogen had reached a plateau. In some systems, the old perfusates were replaced each time with a fresh glycine solution; in others, the initial perfusate was not replaced but only adjusted each time to the original 200 ml volume and a comparable glycine concentration (140 micrograms NH2-N/ml). The incorporation of M enhanced the rates of heterotrophic degradation of glycine and subsequent autotrophic nitrification, but these stimulatory effects decreased with each successive perfusion. The reasons for these decreases are not known, but they did not appear to be related to inorganic nutrition, as perfusion with a mixed cation solution after five perfusion cycles did not significantly enhance nitrification in either the check or M-amended soils during three subsequent perfusions with glycine. The enhancement of nitrification by M appeared to be a result, in part, of the greater buffering capacity of the M-amended soil, as indicated by lesser reductions in the pH of perfusates from the M-amended soil, by titration curves of the soils, and by the greater and longer stimulation of nitrification in the check soil amended with 1% CaCO3, which had a greater buffering capacity than did M. The stimulation by CaCO3 may also have been partially the result of providing CO2 for the autotrophic nitrifyers. Significant concentrations of nitrite accumulated only in perfusates from soil amended with CaCO3. Air-drying and remoistening the soils enhanced nitrification of subsequently added glycine, especially in the check soil. The importance of pH-mediation, of the production of inhibitors, and/or of feed-back inhibition was indicated by the lower rate and extent of nitrification in systems wherein the perfusates were not replaced between successive additions of glycine. Although the results of these studies confirmed previous observations that M enhances the rate of nitrification in soil, the mechanisms responsible for this stimulation are still not known.

• MeSH
• Bentonite pharmacology   MeSH
• Biodegradation, Environmental MeSH
• Stimulation, Chemical MeSH
• Nitrates metabolism   MeSH
• Nitrites metabolism   MeSH
• Glycine pharmacology   MeSH
• Quaternary Ammonium Compounds metabolism   MeSH
• Nitrobacter metabolism   MeSH
• Soil Microbiology * MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bentonite MeSH
• Nitrates MeSH
• Nitrites MeSH
• Glycine MeSH
• Quaternary Ammonium Compounds MeSH

• MeSH
• Ammonia metabolism   MeSH
• Bacteria growth & development   metabolism   MeSH
• Bacteriological Techniques MeSH
• Time Factors MeSH
• Nitrates biosynthesis   MeSH
• Colorimetry MeSH
• Mathematics MeSH
• Soil Microbiology * MeSH
• Temperature MeSH
• Water MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Czechoslovakia MeSH
• Yugoslavia MeSH
• Kenya MeSH
• Zambia MeSH
• Names of Substances
• Ammonia MeSH
• Nitrates MeSH
• Water MeSH

• MeSH
• Culture Media MeSH
• Microbiology * MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Culture Media MeSH