Lead Toxicity and Phosphate Deficiency in <i>Chlamydomonas</i>

Schulze, Heinz; Brand, Jerry J.

doi:10.1104/pp.62.5.727

Cited by 14 publications

(7 citation statements)

References 14 publications

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“…S2). These effects are consistent with prior studies in a number of organisms and cell types demonstrating the impact of Pb 2ϩ on various aspects of metal (37-42), phosphate (43,44), and sulfur homeostasis (45)(46)(47).…”

Section: Stress-induced Heme Signalingsupporting

confidence: 91%

Heme bioavailability and signaling in response to stress in yeast cells

Hanna

Kim

et al. 2018

Journal of Biological Chemistry

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Protoheme (hereafter referred to as heme) is an essential cellular cofactor and signaling molecule that is also potentially cytotoxic. To mitigate heme toxicity, heme synthesis and degradation are tightly coupled to heme utilization in order to limit the intracellular concentration of "free" heme. Such a model, however, would suggest that a readily accessible steady-state, bioavailable labile heme (LH) pool is not required for supporting heme-dependent processes. Using the yeast as a model and fluorescent heme sensors, site-specific heme chelators, and molecular genetic approaches, we found here that 1) yeast cells preferentially use LH in heme-depleted conditions; 2) sequestration of cytosolic LH suppresses heme signaling; and 3) lead (Pb) stress contributes to a decrease in total heme, but an increase in LH, which correlates with increased heme signaling. We also observed that the proteasome is involved in the regulation of the LH pool and that loss of proteasomal activity sensitizes cells to Pb effects on heme homeostasis. Overall, these findings suggest an important role for LH in supporting heme-dependent functions in yeast physiology.

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Section: Stress-induced Heme Signalingsupporting

confidence: 91%

Heme bioavailability and signaling in response to stress in yeast cells

Hanna

Kim

et al. 2018

Journal of Biological Chemistry

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“…A white precipitate was evident upon addition of P043or C032to the Pb-amended medium. The toxicity of Pb to growth of Chlamydomonas reinhardtii was also reduced by the incorporation of P043into the medium (35), and the toxicity of Pb to Tetrahymena pyriformis was greater in soft (20 mg of CaCO3 per liter) than in hard (400 mg of CaCO3 per liter) water (11), possibly due to the formation of greater quantities of PbCO3 in the hard water. Similarly, the sparingly soluble Pb salts, PbO, PbS, and PbCO3.Pb(OH)2, were not toxic to A. niger, whereas equivalent concentrations of free Pb2+ were highly toxic (46).…”

Section: Resultsmentioning

confidence: 99%

“…The addition of 102 M succinic acid to the medium also reduced the inhibitory or lethal effect of 200 ,tg of Pb per ml to R. solani, F. solani, A. giganteus, and C. echinulata (Table 6), probably as a result of the chelation of Pb by the dicarboxylic acid. Chelated forms of Pb were also less toxic to growth of A. niger (46) and C. reinhardtii (35) and were less readily taken up by Phaeodactylum tricornutum (34) than was free Pb.…”

Section: Resultsmentioning

confidence: 99%

Abiotic factors affecting the toxicity of lead to fungi

Babich¹,

Stotzky²

1979

Appl Environ Microbiol

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The toxicity of lead (Pb) to fungi in pure culture was influenced by several abiotic factors: pH, inorganic anions, clay minerals, and particulate (humic acid) and soluble organic matter. The toxicity of Pb was potentiated under acidic conditions (pH 5 and 6), and phosphate or carbonate anions reduced the toxicity, apparently as a result of the formation of sparingly soluble Pb salts. Clay minerals (montmorillonite > attapulgite > kaolinite) and particulate humic acid protected against the toxicity of Pb, presumably as the result of sorption, by cation exchange, of the Pb to the exchange complexes, which reduced its availability for uptake by the fungi. Soluble organics, such as tryptone, yeast extract, cysteine, succinic acid, and increasing concentrations of neopeptone, also reduced the toxicity of Pb.

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“…Since the experiments were done with P-repleted cultures, it was not expected that the algae would suffer P-limitation during exposure, thus, the results support the alternative hypothesis that P–Cu interaction in the media leads to a reduction in Cu bioavailability. It has been shown that phosphate precipitates with other metals and that this leads to decreased metal availability (Schulze and Brand 1978 ; Nalewajko and Paul 1985 ). However, this argument is difficult to apply to natural systems since a copper phosphate precipitate is thermodynamically unlikely to occur in natural waters, because of the presence of competing ligands.…”

Section: Discussionmentioning

confidence: 99%

Influence of phosphorus on copper sensitivity of fluvial periphyton: the role of chemical, physiological and community-related factors

et al. 2009

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The influence of eutrophication of fluvial ecosystems (caused by increased phosphorus concentrations) on periphyton Cu sensitivity is explored from a multi-scale perspective, going from the field to the laboratory. The study design included three tiers: a field study including the characterization of land use and the ecological state of the corresponding river sections in the Fluvià River watershed, an experimental investigation performed with natural periphyton from the previously studied stream sites in indoor channels, and finally a culture study in the laboratory. Results showed that differences in copper sensitivity of natural periphyton communities followed the gradient of nutrient concentration found in the field. Results from the culture experiments demonstrated that both, P-conditions during growth and P-content in the media are important factors modulating the toxicological response of algae to Cu. The observations from this study indicate that the ecological effects of metal pollution in rivers might be obscured by eutrophication.

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Lead Toxicity and Phosphate Deficiency in Chlamydomonas

Abstract: The addition of lead salts to phosphate-containing Chiamydomonas rei.harddi media caused precipitation of Pb3 (PO4)

Cited by 14 publications

References 14 publications

Heme bioavailability and signaling in response to stress in yeast cells

Heme bioavailability and signaling in response to stress in yeast cells

Abiotic factors affecting the toxicity of lead to fungi

Influence of phosphorus on copper sensitivity of fluvial periphyton: the role of chemical, physiological and community-related factors

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