Iron acquisition by Cryptococcus neoformans. 1995

S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
Department of Medical Specialties, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.

Iron is an essential element for the growth and metabolism of microbial cells. Most pathogenic microbes elaborate powerful iron chelating agents (siderophores) to mobilize iron from ferric ligands. The pathogenic yeast, Cryptococcus neoformans has not been found to produce siderophores and its mechanism of iron acquisition is unknown. This investigation explored an alternative pathway for iron acquisition by examining the interactions of iron with the cell surface. Iron uptake experiments were conducted utilizing radiolabelled ferrous iron and ferric iron chelates, with evidence for the presence of iron(II) receptors and the generation of ferrous iron by surface reduction. Hyperbolic kinetics were found when 59FeII was presented to the organism and uptake was blocked with bathophenanthroline sulphonate, an Fe2+ chelator. The yeast also acquired iron as [59Fe3+]-citrate and [59Fe3+]-pyrophosphate while bathophenanthroline sulphonate reduced the acquisition of these ferric ligands by 48% and 52% respectively. Pre-incubation with either ferric ligand also reduced iron acquisition by 50%. KCN inhibited uptake of iron(II) by 90% and uptake of [59Fe3+]-pyrophosphate and [59Fe3+]-citrate by 46% and 56% respectively; dinitrophenol had no effect on these processes. The data suggest that C. neoformans can (i) generate ferrous iron at the cell surface via a reduction of ferric chelates, with the subsequent acquisition of the ferrous iron, and (ii) acquire iron through the interaction of ferric chelates with a surface component.

UI MeSH Term Description Entries
D007501 Iron A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN. Iron-56,Iron 56
D007502 Iron Chelating Agents Organic chemicals that form two or more coordination links with an iron ion. Once coordination has occurred, the complex formed is called a chelate. The iron-binding porphyrin group of hemoglobin is an example of a metal chelate found in biological systems. Iron Chelates,Agents, Iron Chelating,Chelates, Iron,Chelating Agents, Iron
D010618 Phenanthrolines Phenanthroline
D011190 Potassium Cyanide A highly poisonous compound that is an inhibitor of many metabolic processes, but has been shown to be an especially potent inhibitor of heme enzymes and hemeproteins. It is used in many industrial processes. Potassium Cyanide (K(14)CN),Potassium Cyanide (K(C(15)N)),Cyanide, Potassium
D011756 Diphosphates Inorganic salts of phosphoric acid that contain two phosphate groups. Diphosphate,Pyrophosphate Analog,Pyrophosphates,Pyrophosphate Analogs,Analog, Pyrophosphate
D002951 Citrates Derivatives of CITRIC ACID.
D003455 Cryptococcus neoformans A species of the fungus CRYPTOCOCCUS. Its teleomorph is Filobasidiella neoformans. Blastomyces neoformans,Debaryomyces neoformans,Filobasidiella neoformans,Lipomyces neoformans,Saccharomyces neoformans,Torula neoformans,Torulopsis neoformans,Cryptococcus neoformans var. grubii
D004492 Edetic Acid A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive. EDTA,Edathamil,Edetates,Ethylenediaminetetraacetic Acid,Tetracemate,Calcium Disodium Edetate,Calcium Disodium Versenate,Calcium Tetacine,Chelaton 3,Chromium EDTA,Copper EDTA,Coprin,Dicobalt EDTA,Disodium Calcitetracemate,Disodium EDTA,Disodium Ethylene Dinitrilotetraacetate,Distannous EDTA,Edetate Disodium Calcium,Edetic Acid, Calcium Salt,Edetic Acid, Calcium, Sodium Salt,Edetic Acid, Chromium Salt,Edetic Acid, Dipotassium Salt,Edetic Acid, Disodium Salt,Edetic Acid, Disodium Salt, Dihydrate,Edetic Acid, Disodium, Magnesium Salt,Edetic Acid, Disodium, Monopotassium Salt,Edetic Acid, Magnesium Salt,Edetic Acid, Monopotassium Salt,Edetic Acid, Monosodium Salt,Edetic Acid, Potassium Salt,Edetic Acid, Sodium Salt,Ethylene Dinitrilotetraacetate,Ethylenedinitrilotetraacetic Acid,Gallium EDTA,Magnesium Disodium EDTA,N,N'-1,2-Ethanediylbis(N-(carboxymethyl)glycine),Potassium EDTA,Stannous EDTA,Versenate,Versene,Acid, Edetic,Acid, Ethylenediaminetetraacetic,Acid, Ethylenedinitrilotetraacetic,Calcitetracemate, Disodium,Dinitrilotetraacetate, Disodium Ethylene,Dinitrilotetraacetate, Ethylene,Disodium Versenate, Calcium,EDTA, Chromium,EDTA, Copper,EDTA, Dicobalt,EDTA, Disodium,EDTA, Distannous,EDTA, Gallium,EDTA, Magnesium Disodium,EDTA, Potassium,EDTA, Stannous,Edetate, Calcium Disodium,Ethylene Dinitrilotetraacetate, Disodium,Tetacine, Calcium,Versenate, Calcium Disodium
D019343 Citric Acid A key intermediate in metabolism. It is an acid compound found in citrus fruits. The salts of citric acid (citrates) can be used as anticoagulants due to their calcium chelating ability. Citrate,Anhydrous Citric Acid,Citric Acid Monohydrate,Citric Acid, Anhydrous,Uralyt U

Related Publications

S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
December 2013, Current opinion in microbiology,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
February 1997, Infection and immunity,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
January 1992, Journal of medical and veterinary mycology : bi-monthly publication of the International Society for Human and Animal Mycology,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
November 2002, Journal of neuroimmunology,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
December 1987, Journal of medical and veterinary mycology : bi-monthly publication of the International Society for Human and Animal Mycology,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
September 1998, Infection and immunity,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
February 2014, Infection and immunity,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
December 2021, Cellular microbiology,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
April 2013, The Journal of infectious diseases,
S E Vartivarian, and R E Cowart, and E J Anaissie, and T Tashiro, and H A Sprigg
December 2002, Medical mycology,
Copied contents to your clipboard!