Abstract
Calcium (Ca2+) induced changes in growth, heterocyst differentiation, nitrogenase activity, NO-3 uptake, NO-2 efflux and Ca2+ ATPase activity have been studied in the wild type Nostoc MAC (Het- Fox-) and its revertant (Het+ Nif+, R1, R2 and R3) mutant strains. Growth, NO-3 uptake NO-2 efflux and Ca2+- ATPase activities of the wild type Nostoc MAC and its revertant (R1, R2 and R3) mutant strains increased with increase in Ca2+ concentration (0-0.5 mM) being maximum at 0.2mA/ Ca2+. Similarly, heterocyst differentiation and nitrogenase activity in the revertant (R1,R2 and R3) mutant strains of the wild type Nostoc MAC also increased in response to Ca2+ and attained their maximum level at 0.2mM Ca2+. In contrast, 0.13mM Ca2+ which is being used in the growth medium for routine culturing of Nostoc MAC cells could support only lower growth, heterocyst differentiation, nitrogenase activity, NO-3 uptake, NO-2 efflux and Ca2+-ATPsC activities as compared to 0.2mM Ca2+. The cultures devoid of Ca2+ on the other hand, showed lowest growth, heterocyst differentiation, nitrogenase activity, NO-3 uptake, NO-2 efflux and Ca2+-ATPaSe activities. The results suggest that (i) 0.2 mM Ca2+ is well suited for the maximum growth, heterocyst differentiation, nitrogenase activity, NO-3 uptake and NO-2 efflux activities in the wild type as well as its revertant mutant strains instead of 0.13 mM Ca2+ which is generally being used for the routine culturing of the Nostoc MAC and its revertant mutant strains; (ii) Ca2+ appears to have a catalytic role in aerobic nitrogen fixation; and (ii) Ca2+ induced physiological and biochemical changes seem to be due to hange in ATP level.
Original language | English (US) |
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Pages (from-to) | 881-885 |
Number of pages | 5 |
Journal | Indian Journal of Experimental Biology |
Volume | 35 |
Issue number | 8 |
State | Published - Aug 1997 |
Externally published | Yes |
ASJC Scopus subject areas
- Biotechnology
- Molecular Biology
- Cell Biology