Methods for Growing Spirillum lipoferum and for Counting It in Pure Culture and in Association with Plants
- 1 January 1977
- journal article
- research article
- Published by American Society for Microbiology in Applied and Environmental Microbiology
- Vol. 33 (1), 85-88
- https://doi.org/10.1128/aem.33.1.85-88.1977
Abstract
Methods are described for growing S. lipoferum in quantities sufficient to serve as inoculant in field trials of its associative N2-fixing ability with higher plants and as a source of cells for the preparation of nitrogenase, cytochromes, respiratory enzymes, etc. A heavy inoculum of S. lipoferum grown on NH4+ was transferred to a medium of minimal N content, and initial rapid growth at the expense of residual combined N was replaced later by slower growth on N2. Conversion to N2 fixation was prompt upon exhaustion of fixed N; growth on N2 was most rapid at a pO2 [partial O2 pressure] of 0.005-0.007 atm. Numbers of S. lipoferum can be estimated by diluting soil, crushed roots or other material and inoculating diluted samples into a stagnant semisolid medium. Development of a characteristic subsurface layer of organisms and demonstration that these organisms can reduce C2H2 are presumptive evidence that they are S. lipoferum. With most-probable-number [MPN] tables the observations can be converted to numbers of S. lipoferum in the samples. The MPN method indicated that numbers of S. lipoferum may increase .gtoreq. 100-fold in roots of maize removed from the plant and incubated for 24 h at 30.degree. C at a pO2 initially adjusted to 0.01 atm.This publication has 2 references indexed in Scilit:
- The greatest happiness.Journal of Medical Ethics, 1975
- Potential for Nitrogen Fixation in Maize Genotypes in BrazilProceedings of the National Academy of Sciences, 1975