The assimilatory nitrate reduction system of the phototrophic bacterium Rhodobacter capsulatus E1F1

2006 ◽  
Vol 34 (1) ◽  
pp. 127-129 ◽  
Author(s):  
C. Pino ◽  
F. Olmo-Mira ◽  
P. Cabello ◽  
M. Martínez-Luque ◽  
F. Castillo ◽  
...  
Keyword(s):  
Rhodobacter Capsulatus ◽  
Nitrate Assimilation ◽  
Growth Conditions ◽  
Biochemical Properties ◽  
Regulatory Proteins ◽  
Structural Genes ◽  
Phototrophic Bacterium ◽  
Nitrate Sensor ◽  
Assimilatory Nitrate Reduction ◽  
Phototrophic Growth

The phototrophic bacterium Rhodobacter capsulatus E1F1 assimilates nitrate under anaerobic phototrophic growth conditions. A 17 kb DNA region encoding the nitrate assimilation (nas) system of this bacterium has been cloned and sequenced. This region includes the genes coding for a putative ABC (ATP-binding cassette)-type nitrate transporter (nasFED) and the structural genes for the enzymes nitrate reductase (nasA), nitrite reductase (nasB) and hydroxylamine reductase (hcp). Three genes code for putative regulatory proteins: a nitrite-sensitive repressor (nsrR), a transcription antiterminator (nasT) and a nitrate sensor (nasS). Other genes probably involved in nitrate assimilation are also present in this region. The sequence analysis of these genes and the biochemical properties of the purified nitrate, nitrite and hydroxylamine reductases are reviewed.

High-level transcription of large gene regions: a novel T7 RNA-polymerase-based system for expression of functional hydrogenases in the phototrophic bacterium Rhodobacter capsulatus

2005 ◽  
Vol 33 (1) ◽  
pp. 56-58 ◽  
Author(s):  
T. Drepper ◽  
S. Arvani ◽  
F. Rosenau ◽  
S. Wilhelm ◽  
K.-E. Jaeger
Keyword(s):  
Rna Polymerase ◽  
Rhodobacter Capsulatus ◽  
Expression System ◽  
Active Form ◽  
T7 Rna Polymerase ◽  
High Level Synthesis ◽  
Phototrophic Bacterium ◽  
Large Gene ◽  
High Level ◽  
Complex Enzymes

High-level synthesis of complex enzymes like bacterial [NiFe] hydrogenases, in general, requires an expression system that allows concerted expression of a large number of genes. So far, it has not been possible to overproduce a hydrogenase in a stable and active form by using a customary expression system. Therefore we started to establish a new, T7-based expression system in the phototrophic bacterium Rhodobacter capsulatus. The beneficial properties of this bacterial host in combination with the unique capacity of T7 RNA polymerase to synthesize long transcripts will allow the high-level synthesis and assembly of active hydrogenase as well as other complex enzymes in the near future.

Production of Novel Exopolysaccharide with Emulsifying Ability from Marine Microorganism, Alteromonas sp. Strain 00SS11568

2005 ◽  
Vol 277-279 ◽  
pp. 155-161 ◽  
Author(s):  
Joung Han Yim ◽  
Se Hun Ahn ◽  
Sung Jin Kim ◽  
Yoo Kyung Lee ◽  
Kyu Jin Park ◽  
...  
Keyword(s):  
Inorganic Compounds ◽  
Gel Filtration ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Biochemical Properties ◽  
Medium Composition ◽  
Molar Ratio ◽  
Bacterial Strains ◽  
Average Molecular Mass ◽  
Emulsifying Ability

To find a novel exopolysaccharide, marine bacterial strains were isolated from coastal regions of Korea. Strain 00SS11568 was then selected as it produced a mucous exopolysaccharide during the stationary phase in a batch culture. The isolate was identified as Alteromonas sp. based on its 16S rDNA sequence, morphological, and biochemical properties. The exopolysaccharide, designated as p-11568, exhibited an emulsifying ability. The Emulsification Index (E24) of 0.1% p- 11568 was 77.4% with an emulsified kerosene content, and was higher than those of commercial polysaccharides, such as xanthan gum (26.1%), gellan gum (1.3%), and sodium alginate (2.0%). p- 11568 was found to be composed of glucose and galactose as the main natural sugars in a molar ratio of 1.3:1, along with uronic acid (18.9%, w/w) and sulfate groups (1.2% w/w). The average molecular mass was 4.4 x 105 daltons by gel filtration chromatography. The effects of pH, temperature, inorganic compounds, and C and N sources were tested to obtain the optimal medium composition for the production of p-11568. Under optimal growth conditions with the M-11568 medium, 14.9 g of crude p-11568 per liter was obtained.

Degradation of p -nitrophenol by the phototrophic bacterium Rhodobacter capsulatus

1997 ◽  
Vol 169 (1) ◽  
pp. 36-42 ◽  
Author(s):  
M. D. Roldán ◽  
R. Blasco ◽  
F. J. Caballero ◽  
F. Castillo
Keyword(s):  
Rhodobacter Capsulatus ◽  
Phototrophic Bacterium

Effect of growth conditions on electrophysical properties of Rhodobacter capsulatus PG cells

Microbiology ◽  
2008 ◽  
Vol 77 (5) ◽  
pp. 568-571
Author(s):  
S. V. Zubova ◽  
A. Yu. Ivanov ◽  
I. R. Prokhorenko
Keyword(s):  
Rhodobacter Capsulatus ◽  
Growth Conditions ◽  
Electrophysical Properties

scholarly journals Bacterial nitrate assimilation: gene distribution and regulation

2011 ◽  
Vol 39 (6) ◽  
pp. 1838-1843 ◽  
Author(s):  
Víctor M. Luque-Almagro ◽  
Andrew J. Gates ◽  
Conrado Moreno-Vivián ◽  
Stuart J. Ferguson ◽  
David J. Richardson ◽  
...  
Keyword(s):  
Rhodobacter Capsulatus ◽  
Heterotrophic Bacteria ◽  
Azotobacter Vinelandii ◽  
Klebsiella Oxytoca ◽  
Prokaryotic Genome ◽  
Nitrate Assimilation ◽  
Primary Role ◽  
Bacterial Strains ◽  
Global Nitrogen Cycle

In the context of the global nitrogen cycle, the importance of inorganic nitrate for the nutrition and growth of marine and freshwater autotrophic phytoplankton has long been recognized. In contrast, the utilization of nitrate by heterotrophic bacteria has historically received less attention because the primary role of these organisms has classically been considered to be the decomposition and mineralization of dissolved and particulate organic nitrogen. In the pre-genome sequence era, it was known that some, but not all, heterotrophic bacteria were capable of growth on nitrate as a sole nitrogen source. However, examination of currently available prokaryotic genome sequences suggests that assimilatory nitrate reductase (Nas) systems are widespread phylogenetically in bacterial and archaeal heterotrophs. Until now, regulation of nitrate assimilation has been mainly studied in cyanobacteria. In contrast, in heterotrophic bacterial strains, the study of nitrate assimilation regulation has been limited to Rhodobacter capsulatus, Klebsiella oxytoca, Azotobacter vinelandii and Bacillus subtilis. In Gram-negative bacteria, the nas genes are subjected to dual control: ammonia repression by the general nitrogen regulatory (Ntr) system and specific nitrate or nitrite induction. The Ntr system is widely distributed in bacteria, whereas the nitrate/nitrite-specific control is variable depending on the organism.

Sign in / Sign up

Export Citation Format

Share Document