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Appl. Environ. Microbiol., May 1997, 1801-1807, Vol 63, No. 5
P Tamagnini, O Troshina, F Oxelfelt, R Salema and P Lindblad
The present study was carried out in order to examine and characterize the
bidirectional hydrogenase in the cyanobacterium Nostoc sp. strain PCC
73102. Southern hybridizations with the probes Av1 and Av3 (hoxY and hoxH,
bidirectional hydrogenase small and large subunits, respectively) revealed
the occurrence of corresponding sequences in Anabaena variabilis (control),
Anabaena sp. strain PCC 7120, and Nostoc muscorum but not in Nostoc sp.
strain PCC 73102. As a control, hybridizations with the probe hup2 (hupL,
uptake hydrogenase large subunit) demonstrated the presence of a
corresponding gene in all the cyanobacteria tested, including Nostoc sp.
strain PCC 73102. Moreover, with three different growth media, a
bidirectional enzyme that was functional in vivo was observed in N.
muscorum, Anabaena sp. strain PCC 7120, and A. variabilis, whereas Nostoc
sp. strain PCC 73102 consistently lacked any detectable in vivo activity.
Similar results were obtained when assaying for the presence of an enzyme
that is functional in vitro. Native polyacrylamide gel electrophoresis
followed by in situ hydrogenase activity staining was used to demonstrate
the presence or absence of a functional enzyme. Again, bands corresponding
to hydrogenase activity were observed for N. muscorum, Anabaena sp. strain
PCC 7120, and A. variabilis but not for Nostoc sp. strain PCC 73102. In
conclusion, we were unable to detect a bidirectional hydrogenase in Nostoc
sp. strain PCC 73102 with specific physiological and molecular techniques.
The same techniques clearly showed the presence of an inducible
bidirectional enzyme and corresponding structural genes in N. muscorum,
Anabaena sp. strain PCC 7120, and A. variabilis. Hence, Nostoc sp. strain
PCC 73102 seems to be an unusual cyanobacterium and an interesting
candidate for future biotechnological applications.
Copyright © 1997, American Society for Microbiology
Hydrogenases in Nostoc sp. Strain PCC 73102, a Strain Lacking a Bidirectional Enzyme
Department of Physiological Botany, Uppsala University, S-752 36 Uppsala, Sweden; Departamento de Botanica, Faculdade de Ciencias and Instituto de BiologiaMolecular e Celular, Universidade do Porto, 4150 Porto, Portugal; and Institute of Soil Science and Photosynthesis, Russian Academy of Sciences, 142292 Pushchino, Moscow Region, Russia
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