Extracellular Calcium and Magnesium, but Not Iron, Are Needed for Optimal Growth of<i>Blastomyces dermatitidis</i>Yeast Form Cells In Vitro

Giles, Steven S.; Czuprynski, Charles J.

doi:10.1128/cdli.11.2.426-429.2004

Cited by 9 publications

(6 citation statements)

References 23 publications

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“…We used the Chelex-100 resin to eliminate ferrous and ferric iron from traces of reagents in the media, since the resin can be subsequently removed from media, and then the culture is not affected. Chelex-100 also sequesters calcium, magnesium and zinc (Giles & Czuprynski, 2004), but they are restored by the serum added after chelation. Our data also show that bovine holoLf can sustain amoebic growth, but to a lower extent than human holoLf.…”

Section: Discussionmentioning

confidence: 99%

Human hololactoferrin: endocytosis and use as an iron source by the parasite Entamoeba histolytica

et al. 2005

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Entamoeba histolytica is an enteric protozoan that exclusively infects human beings. This parasite requires iron for its metabolic functions. Lactoferrin is a mammalian glycoprotein that chelates extracellular iron on mucosal surfaces, including the surface of the large intestine, where E. histolytica initiates infection. This work examined the interaction in vitro of E. histolytica trophozoites with human hololactoferrin (iron-saturated lactoferrin). A minimum concentration of 50 mM Fe from hololactoferrin supported growth of the amoeba. Amoebic binding sites for hololactoferrin were different from those for human apolactoferrin, holotransferrin and haemoglobin. One amoebic hololactoferrrin-binding polypeptide of 90 kDa was found, which was not observed after treatment of trophozoites with trypsin. Hololactoferrin-binding-protein levels increased in amoebas starved of iron, or grown in hololactoferrin. Internalization of hololactoferrin was inhibited by filipin. Endocytosed hololactoferrin colocalized with an anti-chick embryo caveolin mAb in amoebic vesicles, and lactoferrin was further detected in acidic vesicles; amoebic caveolin of 22 kDa was detected by Western blotting using this antibody. Cysteine proteases from amoebic extracts were able to cleave hololactoferrin. Together, these data indicate that E. histolytica trophozoites bind to hololactoferrin through specific membrane lactoferrin-binding proteins. This ferric protein might be internalized via caveolae-like microdomains, then used as an iron source, and degraded.

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Section: Discussionmentioning

confidence: 99%

Human hololactoferrin: endocytosis and use as an iron source by the parasite Entamoeba histolytica

et al. 2005

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“…The influence of iron on the growth of B . dermatitidis is unclear and one study concluded that iron failed to enhance growth of yeast during iron starvation; however, a high concentration of ferric iron was used [ 34 ]. To further characterize the effect of iron on B .…”

Section: Resultsmentioning

confidence: 99%

Fungal Morphology, Iron Homeostasis, and Lipid Metabolism Regulated by a GATA Transcription Factor in Blastomyces dermatitidis

et al. 2015

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In response to temperature, Blastomyces dermatitidis converts between yeast and mold forms. Knowledge of the mechanism(s) underlying this response to temperature remains limited. In B. dermatitidis, we identified a GATA transcription factor, SREB, important for the transition to mold. Null mutants (SREBΔ) fail to fully complete the conversion to mold and cannot properly regulate siderophore biosynthesis. To capture the transcriptional response regulated by SREB early in the phase transition (0–48 hours), gene expression microarrays were used to compare SREB∆ to an isogenic wild type isolate. Analysis of the time course microarray data demonstrated SREB functioned as a transcriptional regulator at 37°C and 22°C. Bioinformatic and biochemical analyses indicated SREB was involved in diverse biological processes including iron homeostasis, biosynthesis of triacylglycerol and ergosterol, and lipid droplet formation. Integration of microarray data, bioinformatics, and chromatin immunoprecipitation identified a subset of genes directly bound and regulated by SREB in vivo in yeast (37°C) and during the phase transition to mold (22°C). This included genes involved with siderophore biosynthesis and uptake, iron homeostasis, and genes unrelated to iron assimilation. Functional analysis suggested that lipid droplets were actively metabolized during the phase transition and lipid metabolism may contribute to filamentous growth at 22°C. Chromatin immunoprecipitation, RNA interference, and overexpression analyses suggested that SREB was in a negative regulatory circuit with the bZIP transcription factor encoded by HAPX. Both SREB and HAPX affected morphogenesis at 22°C; however, large changes in transcript abundance by gene deletion for SREB or strong overexpression for HAPX were required to alter the phase transition.

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“…The production of reactive oxygen species which are known to cause DNA damage has been shown to be actively reduced upon elevation of Mg 2+ ions, both in yeast and human cells (Maynard, 1993;Maede et al, 2004). The work of Giles and Czuprynski (2004) demonstrates the impact of magnesium ions on yeast growth -where pathogenic fungi Blastomyces dermatitidis showed an enhanced growth at Mg 2+ ion concentration of 0.1 mg/ml. The study by Blazejack (2006) has also implicated magnesium indirectly with the activation of the nutrient uptake and growth machinerywhere magnesium supplementation at levels of 1.25 g/L increased the binding capacity of the metal.…”

Section: Role Of Magnesium In Yeast Physiologymentioning

confidence: 98%

“…Unlike the basic antagonistic relationship of Mg 2+ and Ca 2+ , the work of Giles and Czuprynski (2004) and Trofimova et al (2010) has reported a novel relationship for both metals, as complete restoration of cell growth and enhanced membrane stability for B. dermatitidis and S. cerevisiae respectively were recorded in the presence of Mg 2+ and Ca 2+ . It was hypothesized in the report, that both metals cooperatively stabilizes and reduces fluctuation in plasma membrane fluidity which has been correlatively found to be an inverse function of yeast survival (Simonin et al, 2008).…”

Section: Role Of Magnesium In Yeast Physiologymentioning

confidence: 99%

Role of magnesium ions on yeast performance during very high gravity fermentation

Udeh¹,

Kgatla²

2013

J. Brew. Distilling

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The advent of highly efficient, environmentally friendly and cost effective fermentation technology has given impetus to research in the field of optimizing nutritional parameters for optimum yeast fermentative performance. Very high gravity fermentation is a novel fermentation technology that provides an increased production capacity from same size fermentation facilities, with outstanding benefits that includes: high ethanol yield per fermentable mash, considerable savings in energy and process water usage, and effluents with low biological oxygen demand amongst others. Limitations to full commercialization of the technology have been attributed to deleterious effects of the fermentation condition on yeast physiology which include high osmotic stress and ethanol toxicity amongst others. The impact of these physiological stresses on yeast cells during high substrate fermentation manifest as sluggish and incomplete fermentation with high residual sugars in beer, reduced ethanol yield, disproportionate synthesis of esters and generation of respiratory deficient yeast crop. However, compelling evidence has implicated magnesium ions with numerous biological processes and more importantly, with the role of curtailing the impact of these stress conditions. Hence, this review highlights two potential stress conditions of very high gravity fermentation; their mechanism of inhibition versus yeast stress response mechanism, role of magnesium ions in yeast physiology and its impact on fermentation processes. The knowledge emphasized herein will be of practical importance to industrial fermentation processes, as it provides feasible clues to improving yeast fermentative performance under high substrate conditions -with perspectives to precise magnesium regulation in yeast.

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Extracellular Calcium and Magnesium, but Not Iron, Are Needed for Optimal Growth ofBlastomyces dermatitidisYeast Form Cells In Vitro

Cited by 9 publications

References 23 publications

Human hololactoferrin: endocytosis and use as an iron source by the parasite Entamoeba histolytica

Human hololactoferrin: endocytosis and use as an iron source by the parasite Entamoeba histolytica

Fungal Morphology, Iron Homeostasis, and Lipid Metabolism Regulated by a GATA Transcription Factor in Blastomyces dermatitidis

Role of magnesium ions on yeast performance during very high gravity fermentation

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