Document Detail

Responses of Azospirillum brasilense to nitrogen deficiency and to wheat lectin: a diffuse reflectance infrared fourier transform (DRIFT) spectroscopic study.
MedLine Citation:
PMID:  18437449     Owner:  NLM     Status:  MEDLINE    
For the rhizobacterium Azospirillum brasilense, the optimal nutritional range of C:N ratios corresponds to the presence of malate (ca. 3 to 5 g l(-1) of its sodium salt) and ammonium (ca. 0.5 to 3 g l(-1) of NH4Cl) as preferred carbon and nitrogen sources, respectively. This microaerophilic aerotactic bacterium is known to have a narrow optimal oxygen concentration range of ca. 3 to 5 microM, which is 1.2% to 2% of oxygen solubility in air-saturated water under normal conditions. In this work, the effects of stress conditions (bound-nitrogen deficiency related to a high C:N ratio in the medium; excess of oxygen) on aerobically grown A. brasilense Sp245, a native wheat-associated endophyte, were investigated in the absence and presence of wheat germ agglutinin (WGA, plant stress protein and a molecular host-plant signal for the bacterium) using FTIR spectroscopy of whole cells in the diffuse reflectance mode (DRIFT). The nutritional stress resulted in the appearance of prominent spectroscopic signs of poly-3-hydroxybutyrate (PHB) accumulation in the bacterial cells; in addition, splitting of the amide I band related to bacterial cellular proteins indicated some stress-induced alterations in their secondary structure components. Similar structural changes were observed in the presence of nanomolar WGA both in stressed A. brasilense cells and under normal nutritional conditions. Comparative analysis of the data obtained and the relevant literature data indicated that the stress conditions applied (which resulted in the accumulation of PHB involved in stress tolerance) and/or the presence of nanomolar concentrations of WGA induced synthesis of bacterial cell-surface (glyco)proteins rich in beta-structures, that could be represented by hemagglutinin and/or porin.
Alexander A Kamnev; Julia N Sadovnikova; Petros A Tarantilis; Moschos G Polissiou; Lyudmila P Antonyuk
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-04-25
Journal Detail:
Title:  Microbial ecology     Volume:  56     ISSN:  0095-3628     ISO Abbreviation:  Microb. Ecol.     Publication Date:  2008 Nov 
Date Detail:
Created Date:  2008-10-08     Completed Date:  2009-01-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7500663     Medline TA:  Microb Ecol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  615-24     Citation Subset:  IM    
Laboratory of Biochemistry, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prosp. Entuziastov, 410049 Saratov, Russia.
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MeSH Terms
Azospirillum brasilense / drug effects*,  growth & development,  metabolism
Hydroxybutyrates / metabolism
Nitrogen / metabolism*,  pharmacology
Polyesters / metabolism
Spectroscopy, Fourier Transform Infrared / methods*
Wheat Germ Agglutinins / pharmacology*
Reg. No./Substance:
0/Hydroxybutyrates; 0/Polyesters; 0/Wheat Germ Agglutinins; 26063-00-3/poly-beta-hydroxybutyrate; 7727-37-9/Nitrogen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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