scholarly journals Examining pathways of iron and sulfur acquisition, trafficking, deployment, and storage in mineral-grown methanogen cells

2021 ◽  
Author(s):  
Devon Payne ◽  
Eric M. Shepard ◽  
Rachel L. Spietz ◽  
Katherine Steward ◽  
Sue Brumfield ◽  
...  
Keyword(s):  
Iron Sulfide ◽  
Storage Proteins ◽  
Spectral Feature ◽  
Methanogenic Archaea ◽  
Sulfide Mineral ◽  
Methanococcus Voltae ◽  
Fe Content ◽  
And Storage ◽  
Fe Acquisition ◽  
Excess Fe

Methanogens have a high demand for iron (Fe) and sulfur (S); however, little is known of how they acquire, deploy, and store these elements and how this, in turn, affects their physiology. Methanogens were recently shown to reduce pyrite (FeS 2 ) generating aqueous iron-sulfide (FeS (aq) ) clusters that are likely assimilated as a source of Fe and S. Here, we compare the phenotype of Methanococcus voltae when grown with FeS 2 or ferrous iron (Fe(II)) and sulfide (HS - ). FeS 2 -grown cells are 33% smaller yet have 193% more Fe than Fe(II)/HS - -grown cells. Whole cell EPR revealed similar distributions of paramagnetic Fe, although FeS 2 -grown cells showed a broad spectral feature attributed to intracellular thioferrate-like nanoparticles. Differential proteomic analyses showed similar expression of core methanogenesis enzymes, indicating that Fe and S source does not substantively alter the energy metabolism of cells. However, a homolog of the Fe(II) transporter FeoB and its putative transcriptional regulator DtxR were up-expressed in FeS 2 -grown cells, suggesting that cells sense Fe(II) limitation. Two homologs of IssA, a protein putatively involved in coordinating thioferrate nanoparticles, were also up-expressed in FeS 2 -grown cells. We interpret these data to indicate that, in FeS 2 -grown cells, DtxR cannot sense Fe(II) and therefore cannot down-regulate FeoB. We suggest this is due to the transport of Fe(II) complexed with sulfide (FeS (aq) ) leading to excess Fe that is sequestered by IssA as a thioferrate-like species. This model provides a framework for the design of targeted experiments aimed at further characterizing Fe acquisition and homeostasis in M. voltae and other methanogens. IMPORTANCE FeS 2 is the most abundant sulfide mineral in the Earth’s crust and is common in environments inhabited by methanogenic archaea. FeS 2 can be reduced by methanogens, yielding aqueous FeS (aq) clusters that are thought to be a source of Fe and S. Here, we show that growth of Methanococcus voltae on FeS 2 results in smaller cell size and higher Fe content per cell, with Fe likely stored intracellularly as thioferrate-like nanoparticles. Fe(II) transporters and storage proteins were up-regulated in FeS 2 -grown cells. These responses are interpreted to result from cells incorrectly sensing Fe(II) limitation due to assimilation of Fe(II) as FeS (aq) . These findings have implications for our understanding of how Fe/S availability influences methanogen physiology and the biogeochemical cycling of these elements.

Reaction pathways of iron-sulfide mineral formation: an in situ X-ray diffraction study

2018 ◽  
Vol 30 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Min-Yu Lin ◽  
Yen-Hua Chen ◽  
Jey-Jau Lee ◽  
Hwo-Shuenn Sheu
Keyword(s):  
Diffraction Study ◽  
Iron Sulfide ◽  
Sulfide Mineral ◽  
Reaction Pathways ◽  
Mineral Formation ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Water Stress and Storage-protein Degradation during Germination of Impatiens Seed

1991 ◽  
Vol 116 (2) ◽  
pp. 302-306 ◽  
Author(s):  
Mehrassa Khademi ◽  
David S. Koranski ◽  
David J. Hannapel ◽  
Allen D. Knapp ◽  
Richard J. Gladon
Keyword(s):  
Water Stress ◽  
Storage Proteins ◽  
Dry Weight ◽  
Insoluble Fraction ◽  
Weight Basis ◽  
Optimum Conditions ◽  
Fresh Weight ◽  
Soluble Protein Fraction ◽  
Molecular Weights ◽  
And Storage

Water uptake by impatiens (Impatiens wallerana Hook. f. cv. Super Elfin Coral) seeds was measured as an increase in fresh weight every 24 hours during 144 hours of germination. Seeds absorbed most of the water required for germination within 3 hours of imbibition and germinated at 60% to 67% moisture on a dry-weight basis. Germination started at 48 hours and was complete by 96 hours at 25C. Water stress of -0.1, -0.2, -0.4, and -0.6 MPa, induced by polyethylene glycol 8000, reduced germination by 13%, 49%, 91%, and 100%, respectively, at 96 hours. Under the same water-stress conditions, increases in fresh weight were inhibited by 53%, 89%, 107%, and 106%, respectively. Three distinct groups of storage proteins were present in dry seed; their estimated molecular weights were 1) 35, 33, and 31 kDa; 2) 26, 23, and 21 kDa; and 3) two bands <14 kDa. Major depletion of storage proteins coincided with the completion of germination. Water potentials that inhibited germination also inhibited degradation of storage proteins. During germination under optimum conditions, the soluble protein fraction increased, coinciding with a decrease in the insoluble fraction.

scholarly journals Protein analysis reveals differential accumulation of late embryogenesis abundant and storage proteins in seeds of wild and cultivated amaranth species

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Esaú Bojórquez-Velázquez ◽  
Alberto Barrera-Pacheco ◽  
Eduardo Espitia-Rangel ◽  
Alfredo Herrera-Estrella ◽  
Ana Paulina Barba de la Rosa
Keyword(s):  
Storage Proteins ◽  
Protein Analysis ◽  
Late Embryogenesis Abundant ◽  
Late Embryogenesis ◽  
Amaranth Species ◽  
And Storage

The functional status of paraveinal mesophyll vacuoles changes in response to altered metabolic conditions in soybean leaves

2005 ◽  
Vol 32 (4) ◽  
pp. 335 ◽  
Author(s):  
Kimberly A. Murphy ◽  
Rachel A. Kuhle ◽  
Andreas M. Fischer ◽  
Aldwin M. Anterola ◽  
Howard D. Grimes
Keyword(s):  
Functional Status ◽  
Storage Proteins ◽  
Vegetative Storage Proteins ◽  
Paraveinal Mesophyll ◽  
Lytic Function ◽  
Metabolic Conditions ◽  
Glycine Max L ◽  
Soybean Leaves ◽  
And Storage ◽  
Lytic Compartment

Antibodies raised against tonoplast intrinsic proteins (TIPs) were used to probe the functional status of the soybean [Glycine max (L.) Merr.] paraveinal mesophyll (PVM) vacuole during changes in nitrogen metabolism within the leaf. Young plants grown under standard conditions had PVM vacuoles characterised by the presence of γ-TIP, which is indicative of a lytic function. When plants were then subjected to shoot tip removal for a period of 15 d, forcing a sink-limited physiological condition, the γ-TIP marker diminished while the δ-TIP marker became present in the PVM vacuole, indicating the conversion of the PVM vacuole to a storage function. When the shoot tips were allowed to regrow, the γ-TIP marker again became dominant demonstrating the reversion of these PVM vacuoles back to a lytic compartment. The changes in TIP markers correlated with the accumulation of vegetative storage proteins and vegetative lipoxygenases, proteins implicated in nitrogen storage and assimilate partitioning. This research suggests that the PVM vacuole is able to undergo dynamic conversion between lytic and storage functions and further implicates this cell layer in assimilate storage and mobilisation in soybeans.

scholarly journals Metagenomes and metatranscriptomes from boreal potential and actual acid sulfate soil materials

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Eva Högfors-Rönnholm ◽  
Margarita Lopez-Fernandez ◽  
Stephan Christel ◽  
Diego Brambilla ◽  
Marcel Huntemann ◽  
...  
Keyword(s):  
Iron Sulfide ◽  
Atmospheric Oxygen ◽  
Sulfide Mineral ◽  
Rrna Gene ◽  
Acid Sulfate Soils ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Potential Acid ◽  
The Baltic ◽  
Sulfate Soils

Abstract Natural sulfide rich deposits are common in coastal areas worldwide, including along the Baltic Sea coast. When artificial drainage exposes these deposits to atmospheric oxygen, iron sulfide minerals in the soils are rapidly oxidized. This process turns the potential acid sulfate soils into actual acid sulfate soils and mobilizes large quantities of acidity and leachable toxic metals that cause severe environmental problems. It is known that acidophilic microorganisms living in acid sulfate soils catalyze iron sulfide mineral oxidation. However, only a few studies regarding these communities have been published. In this study, we sampled the oxidized actual acid sulfate soil, the transition zone where oxidation is actively taking place, and the deepest un-oxidized potential acid sulfate soil. Nucleic acids were extracted and 16S rRNA gene amplicons, metagenomes, and metatranscriptomes generated to gain a detailed insight into the communities and their activities. The project will be of great use to microbiologists, environmental biologists, geochemists, and geologists as there is hydrological and geochemical monitoring from the site stretching back for many years.

Deep abiotic weathering of pyrite

Science ◽  
2020 ◽  
Vol 370 (6515) ◽  
pp. eabb8092
Author(s):  
Xin Gu ◽  
Peter J. Heaney ◽  
Fabio D. A. Aarão Reis ◽  
Susan L. Brantley
Keyword(s):  
Large Scale ◽  
Iron Sulfide ◽  
Atmospheric Oxygen ◽  
Pyrite Oxidation ◽  
Microscopic Analysis ◽  
Sulfide Mineral ◽  
Early Atmosphere ◽  
Sulfur Oxidizing ◽  
Pyrite Weathering ◽  
Grain Surface

Pyrite is a ubiquitous iron sulfide mineral that is oxidized by trace oxygen. The mineral has been largely absent from global sediments since the rise in oxygen concentration in Earth’s early atmosphere. We analyzed weathering in shale, the most common rock exposed at Earth’s surface, with chemical and microscopic analysis. By looking across scales from 10−9 to 102 meters, we determined the factors that control pyrite oxidation. Under the atmosphere today, pyrite oxidation is rate-limited by diffusion of oxygen to the grain surface and regulated by large-scale erosion and clast-scale fracturing. We determined that neither iron- nor sulfur-oxidizing microorganisms control global pyrite weathering fluxes despite their ability to catalyze the reaction. This multiscale picture emphasizes that fracturing and erosion are as important as atmospheric oxygen in limiting pyrite reactivity over Earth’s history.

scholarly journals Sulfur modulates yield and storage proteins in soybean grains

2021 ◽  
Vol 78 (1) ◽  
Author(s):  
Thiago Bergamini Ibañez ◽  
Luiz Felipe de Melo Santos ◽  
Allan de Marcos Lapaz ◽  
Igor Virgilio Ribeiro ◽  
Filipe Virgilio Ribeiro ◽  
...  
Keyword(s):  
Storage Proteins ◽  
And Storage

scholarly journals An Iron Transporter Is Involved in Iron Homeostasis, Energy Metabolism, Oxidative Stress, and Metacyclogenesis in Trypanosoma cruzi

2022 ◽  
Vol 11 ◽  
Author(s):  
Claudia F. Dick ◽  
Nathália Rocco-Machado ◽  
André L. A. Dos-Santos ◽  
Luiz F. Carvalho-Kelly ◽  
Carolina L. Alcantara ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Metabolic Pathways ◽  
Iron Homeostasis ◽  
Optimal Growth ◽  
Limited Information ◽  
Fe Content ◽  
Fe Uptake ◽  
And Storage ◽  
Regular Medium ◽  
Very High

The parasite Trypanosoma cruzi causes Chagas’ disease; both heme and ionic Fe are required for its optimal growth, differentiation, and invasion. Fe is an essential cofactor in many metabolic pathways. Fe is also harmful due to catalyzing the formation of reactive O2 species; for this reason, all living systems develop mechanisms to control the uptake, metabolism, and storage of Fe. However, there is limited information available on Fe uptake by T. cruzi. Here, we identified a putative 39-kDa Fe transporter in T. cruzi genome, TcIT, homologous to the Fe transporter in Leishmania amazonensis and Arabidopsis thaliana. Epimastigotes grown in Fe-depleted medium have increased TcIT transcription compared with controls grown in regular medium. Intracellular Fe concentration in cells maintained in Fe-depleted medium is lower than in controls, and there is a lower O2 consumption. Epimastigotes overexpressing TcIT, which was encountered in the parasite plasma membrane, have high intracellular Fe content, high O2 consumption—especially in phosphorylating conditions, high intracellular ATP, very high H2O2 production, and stimulated transition to trypomastigotes. The investigation of the mechanisms of Fe transport at the cellular and molecular levels will assist in elucidating Fe metabolism in T. cruzi and the involvement of its transport in the differentiation from epimastigotes to trypomastigotes, virulence, and maintenance/progression of the infection.

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