ISSN:
1432-072X
Keywords:
Begglatoa spp.
;
Ribulose-1,5-bisphosphate carboxylase
;
Phosphoribulokinase
;
Regulation of Calvin-cycle enzymes
;
Heterologous gene-probe hybridization
;
Non-autotrophic sulfur bacteria
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract To date only marine strains of the genus Beggiatoa have been proven to have the capacity for lithoautotrophic growth. The two best characterized freshwater strains (B18LD and OH-75-2a) — previously tested with no evidence of autotrophic potential — were reinvestigated in the current study. Heterotrophically grown cells from exponential or early stationary phase showed extremely low ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) activities (0.002–0.2 nmol CO2·mg prot-1 min-1). After acetate limitation terminated growth both strains demonstrated increased RuBisCO activity with a maximum achieved 1–3 days into stationary phase. For a single growth cycle, activity could increase by more than 100-fold (strain OH-75-2a), but the highest activity achieved was less than 5% of that observed in a lithoautotrophic control. Phosphoribulokinase activity was approximately an order of magnitude greater than the corresponding RuBisCO activity and showed a similar pattern of regulation. A gene probe derived from the RuBisCO large subunit gene of Anacystis nidulans hybridized strongly with DNA from strain OH-75-2a and the autotrophic marine control but not with DNA from strain B18LD.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00444662
Permalink
