Effect of phosphate and oxygen concentrations on alginate production and stoichiometry of metabolism of Azotobacter vinelandii under microaerobic conditions

1999 ◽  
Vol 52 (6) ◽  
pp. 773-780 ◽  
Author(s):  
W. Sabra ◽  
A. -P. Zeng ◽  
S. Sabry ◽  
S. Omar ◽  
W. -D. Deckwer
2006 ◽  
Vol 188 (23) ◽  
pp. 8013-8021 ◽  
Author(s):  
Alexander Schenk ◽  
Michael Berger ◽  
Lisa M. Keith ◽  
Carol L. Bender ◽  
Georgi Muskhelishvili ◽  
...  

ABSTRACT The phytopathogenic bacterium Pseudomonas syringae pv. glycinea infects soybean plants and causes bacterial blight. In addition to P. syringae, the human pathogen Pseudomonas aeruginosa and the soil bacterium Azotobacter vinelandii produce the exopolysaccharide alginate, a copolymer of d-mannuronic and l-guluronic acids. Alginate production in P. syringae has been associated with increased fitness and virulence in planta. Alginate biosynthesis is tightly controlled by proteins encoded by the algT-muc regulatory gene cluster in P. aeruginosa and A. vinelandii. These genes encode the alternative sigma factor AlgT (σ22), its anti-sigma factors MucA and MucB, MucC, a protein with a controversial function that is absent in P. syringae, and MucD, a periplasmic serine protease and homolog of HtrA in Escherichia coli. We compared an alginate-deficient algT mutant of P. syringae pv. glycinea with an alginate-producing derivative in which algT is intact. The alginate-producing derivative grew significantly slower in vitro growth but showed increased epiphytic fitness and better symptom development in planta. Evaluation of expression levels for algT, mucA, mucB, mucD, and algD, which encodes an alginate biosynthesis gene, showed that mucD transcription is not dependent on AlgT in P. syringae in vitro. Promoter mapping using primer extension experiments confirmed this finding. Results of reverse transcription-PCR demonstrated that algT, mucA, and mucB are cotranscribed as an operon in P. syringae. Northern blot analysis revealed that mucD was expressed as a 1.75-kb monocistronic mRNA in P. syringae.


1998 ◽  
Vol 20 (3-4) ◽  
pp. 171-176 ◽  
Author(s):  
E Parente ◽  
M A Crudele ◽  
M Aquino ◽  
F Clementi

2020 ◽  
Vol 92 (9) ◽  
pp. 1198-1198
Author(s):  
S. Stachurski ◽  
H. Salgado-Lugo ◽  
C. F. Peña Malacara ◽  
J. Büchs

2002 ◽  
Vol 38 (2) ◽  
pp. 273-278 ◽  
Author(s):  
N Saude ◽  
H Chèze-Lange ◽  
D Beunard ◽  
P Dhulster ◽  
D Guillochon ◽  
...  

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