Biomaterial Database

Rhizobacterial glutathione levels as affected by starvation and cadmium exposure. 1998

M Hultberg

Department of Horticulture, Swedish University of Agriculture Sciences, Box 55, SE-230 53 Alnarp, Sweden.

The rhizosphere is a continuously fluctuating environment in which severe stresses are put on its inhabitants, and glutathione, a reducing tripeptide, and related compounds probably have important roles in cellular protection. In the present study the metabolism of glutathione was examined in rhizobacteria subjected to stress. The plant-growth-promoting rhizobacterium Pseudomonas fluorescens 5.014 and its mutant 5-2/4 were exposed to starvation, either by resuspension or exhaustion, and to cadmium. Glutathione levels, cell protein, and viable count were determined and compared in different conditions. Both starvation and cadmium exposure decreased the amount of glutathione in the cell. No changes of the glutathione concentration in the medium were observed with or without the presence of rhizobacteria, indicating that there was no transport over the cell membrane. The glutathione levels within the rhizobacteria may give valuable information on how different stresses affect the bacteria. In this study, the involvement of glutathione in the increased stress resistance earlier observed in nutrient-starved P. fluorescens was not supported. The concentration of bacterial glutathione is suggested as a possible marker for rhizosphere competence, which, however, needs to be further evaluated with several strains of rhizobacteria.

UI	MeSH Term	Description	Entries
D011551	Pseudomonas fluorescens	A species of nonpathogenic fluorescent bacteria found in feces, sewage, soil, and water, and which liquefy gelatin.	Bacillus fluorescens,Bacillus fluorescens liquefaciens,Bacterium fluorescens,Liquidomonas fluorescens
D002104	Cadmium	An element with atomic symbol Cd, atomic number 48, and atomic weight 112.41. It is a metal and ingestion will lead to CADMIUM POISONING.
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D005978	Glutathione	A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.	Reduced Glutathione,gamma-L-Glu-L-Cys-Gly,gamma-L-Glutamyl-L-Cysteinylglycine,Glutathione, Reduced,gamma L Glu L Cys Gly,gamma L Glutamyl L Cysteinylglycine
D015169	Colony Count, Microbial	Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.	Agar Dilution Count,Colony-Forming Units Assay, Microbial,Fungal Count,Pour Plate Count,Spore Count,Spread Plate Count,Streak Plate Count,Colony Forming Units Assay, Microbial,Colony Forming Units Assays, Microbial,Agar Dilution Counts,Colony Counts, Microbial,Count, Agar Dilution,Count, Fungal,Count, Microbial Colony,Count, Pour Plate,Count, Spore,Count, Spread Plate,Count, Streak Plate,Counts, Agar Dilution,Counts, Fungal,Counts, Microbial Colony,Counts, Pour Plate,Counts, Spore,Counts, Spread Plate,Counts, Streak Plate,Dilution Count, Agar,Dilution Counts, Agar,Fungal Counts,Microbial Colony Count,Microbial Colony Counts,Pour Plate Counts,Spore Counts,Spread Plate Counts,Streak Plate Counts