Response of Thiobacillus ferrooxidans to phosphate limitation

Abstract

Phosphate ion is an essential nutrient for all cells. Consequently, starvation for this component may constitute a stressing condition which affects the bioleaching capacity of the biomining microorganisms. Therefore, we have studied the manner in which the chemolithotroph Thiobacillus ferrooxidans responds to phosphate limitation. Under these circumstances the bacteria reduced its growth rate, capacity to oxidize ferrous iron and to fix CO,. Concomitant with these changes, the cells showed an increased synthesis of several proteins, some of which were exclusively synthesized during phosphate starvation. When intact cells grown in the absence of phosphate were labelled with z251, several proteins were iodinated in addition of those observed in control cells, suggesting that the lack of phosphate induces some proteins located in the membranes or the periplasmic space of the bacteria. It is expected that by measuring the levels of expression of some of the proteins induced by the shortage of phosphorus, it might be possible to estimate in situ the relative physiological condition of the bacteria in a given bioleaching operation.

Heat and phosphate starvation effects on the proteome, morphology and chemical composition of the biomining bacteria Acidithiobacillus ferrooxidans

“…form filaments (Holmquist and Kjelleberg 1993). In agreement with our work, Seeger and Jerez (1993) showed that A. ferrooxidans strain R2 also forms filaments under phosphate starvation conditions. The mechanisms responsible for the elongation that occurs when bacterial cells are subjected to non-optimal temperatures and to phosphate starvation are not clear.…”

“…These proteins are involved in CO 2 fixation, and the decreased expression of these proteins at 40°C suggests that the ability of A. ferrooxidans to fix CO 2 may be affected by this stress condition, as previously observed by Seeger and Jerez (1993). Since carbon dioxide serves as the sole source of carbon for a diverse array of obligate chemolithoautotroph bacteria, alterations in carbon metabolism are expected to be related to CO 2 fixation.…”

“…In contrast, when the bacteria were grown in the absence of K 2 HPO 4 , a slight decrease in carbohydrates was observed. According to Seeger and Jerez (1993), A. ferrooxidans cells under phosphate starvation reduce their capacity to fix CO 2 . It is possible that under such conditions the bacteria have less carbon to supply their needs, and this could be a possible explanation for the observed decrease in carbohydrates.…”

“…Regarding phosphate starvation, Seeger and Jerez (1993) showed a reduction in the A. ferrooxidans growth rate as well as in its capacity to oxidize ferrous iron and to fix CO 2 . Seeger et al (1996) observed a protein phosphorylation increase in A. ferrooxidans cells submitted to phosphate starvation.…”

Selective Inhibition of the Oxidation of Ferrous Iron or Sulfur in Thiobacillus ferrooxidans

“…Cells grown with phosphate limitation present a filamentous morphology due to a lack of cell division (31,32). Phosphate starvation studies show changes in the degree of synthesis of at least 25 proteins, some of which are exclusively synthesized under starvation conditions (30)(31)(32).…”