Toxic Effects of Chromium(VI) on Anaerobic and Aerobic Growth of Shewanella oneidensis MR-1

2008 ◽  
Vol 20 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Sridhar Viamajala ◽  
Brent M. Peyton ◽  
Rajesh K. Sani ◽  
William A. Apel ◽  
James N. Petersen
Keyword(s):  
Shewanella Oneidensis ◽  
Toxic Effects ◽  
Aerobic Growth ◽  
Chromium Vi

scholarly journals Factors Contributing to Hydrogen Peroxide Resistance in Streptococcus pneumoniae Include Pyruvate Oxidase (SpxB) and Avoidance of the Toxic Effects of the Fenton Reaction

2003 ◽  
Vol 185 (23) ◽  
pp. 6815-6825 ◽  
Author(s):  
Christopher D. Pericone ◽  
Sunny Park ◽  
James A. Imlay ◽  
Jeffrey N. Weiser
Keyword(s):  
Hydrogen Peroxide ◽  
Streptococcus Pneumoniae ◽  
Fenton Reaction ◽  
Bacterial Species ◽  
Atp Depletion ◽  
Host Cells ◽  
Toxic Effects ◽  
Aerobic Growth ◽  
Pyruvate Oxidase ◽  
Cytotoxic Effects

ABSTRACT Aerobic growth of Streptococcus pneumoniae results in production of amounts of hydrogen peroxide (H2O2) that may exceed 1 mM in the surrounding media. H2O2 production by S. pneumoniae has been shown to kill or inhibit the growth of other respiratory tract flora, as well as to have cytotoxic effects on host cells and tissue. The mechanisms allowing S. pneumoniae, a catalase-deficient species, to survive endogenously generated concentrations of H2O2 that are sufficient to kill other bacterial species is unknown. In the present study, pyruvate oxidase (SpxB), the enzyme responsible for endogenous H2O2 production, was required for survival during exposure to high levels (20 mM) of exogenously added H2O2. Pretreatment with H2O2 did not increase H2O2 resistance in the mutant, suggesting that SpxB activity itself is required, rather than an H2O2-inducible pathway. SpxB mutants synthesized 85% less acetyl-phosphate, a potential source of ATP. During H2O2 exposure, ATP levels decreased more rapidly in spxB mutants than in wild-type cells, suggesting that the increased killing of spxB mutants was due to more rapid ATP depletion. Together, these data support the hypothesis that S. pneumoniae SpxB contributes to an H2O2-resistant energy source that maintains viability during oxidative stress. Thus, SpxB is required for resistance to the toxic by-product of its own activity. Although H2O2-dependent hydroxyl radical production and the intracellular concentration of free iron were similar to that of Escherichia coli, killing by H2O2 was unaffected by iron chelators, suggesting that S. pneumoniae has a novel mechanism to avoid the toxic effects of the Fenton reaction.

Dynamic modeling of aerobic growth of Shewanella oneidensis. Predicting triauxic growth, flux distributions, and energy requirement for growth

2013 ◽  
Vol 15 ◽  
pp. 25-33 ◽  
Author(s):  
Hyun-Seob Song ◽  
Doraiswami Ramkrishna ◽  
Grigoriy E. Pinchuk ◽  
Alexander S. Beliaev ◽  
Allan E. Konopka ◽  
...  
Keyword(s):  
Dynamic Modeling ◽  
Energy Requirement ◽  
Shewanella Oneidensis ◽  
Aerobic Growth

scholarly journals Chromium(VI) Toxicity in Legume Plants: Modulation Effects of Rhizobial Symbiosis

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Uliana Ya. Stambulska ◽  
Maria M. Bayliak ◽  
Volodymyr I. Lushchak
Keyword(s):  
Oxidative Stress ◽  
Plant Biomass ◽  
Environmental Pollutants ◽  
Toxic Effects ◽  
Pigment Synthesis ◽  
Chromium Vi ◽  
Rhizobial Symbiosis ◽  
Promote Plant Growth ◽  
Legume Plants ◽  
Cellular Components

Most legume species have the ability to establish a symbiotic relationship with soil nitrogen-fixing rhizobacteria that promote plant growth and productivity. There is an increasing evidence of reactive oxygen species (ROS) important role in formation of legume-rhizobium symbiosis and nodule functioning. Environmental pollutants such as chromium compounds can cause damage to rhizobia, legumes, and their symbiosis. In plants, toxic effects of chromium(VI) compounds are associated with the increased production of ROS and oxidative stress development as well as with inhibition of pigment synthesis and modification of virtually all cellular components. These metabolic changes result in inhibition of seed germination and seedling development as well as reduction of plant biomass and crop yield. However, if plants establish symbiosis with rhizobia, heavy metals are accumulated preferentially in nodules decreasing the toxicity of metals to the host plant. This review summarizes data on toxic effects of chromium on legume plants and legume-rhizobium symbiosis. In addition, we discussed the role of oxidative stress in both chromium toxicity and formation of rhizobial symbiosis and use of nodule bacteria for minimizing toxic effects of chromium on plants.

scholarly journals Global Molecular and Morphological Effects of 24-Hour Chromium(VI) Exposure on Shewanella oneidensis MR-1

2006 ◽  
Vol 72 (9) ◽  
pp. 6331-6344 ◽  
Author(s):  
Karuna Chourey ◽  
Melissa R. Thompson ◽  
Jennifer Morrell-Falvey ◽  
Nathan C. VerBerkmoes ◽  
Steven D. Brown ◽  
...  
Keyword(s):  
Untreated Control ◽  
Expression Profiles ◽  
Shewanella Oneidensis ◽  
Transcriptome Profiling ◽  
Molecular Response ◽  
Chromium Vi ◽  
Stress Protection ◽  
Gene And Protein Expression ◽  
Genes Encoding ◽  
Protein Expression Profiles

ABSTRACT The biological impact of 24-h (“chronic”) chromium(VI) [Cr(VI) or chromate] exposure on Shewanella oneidensis MR-1 was assessed by analyzing cellular morphology as well as genome-wide differential gene and protein expression profiles. Cells challenged aerobically with an initial chromate concentration of 0.3 mM in complex growth medium were compared to untreated control cells grown in the absence of chromate. At the 24-h time point at which cells were harvested for transcriptome and proteome analyses, no residual Cr(VI) was detected in the culture supernatant, thus suggesting the complete uptake and/or reduction of this metal by cells. In contrast to the untreated control cells, Cr(VI)-exposed cells formed apparently aseptate, nonmotile filaments that tended to aggregate. Transcriptome profiling and mass spectrometry-based proteomic characterization revealed that the principal molecular response to 24-h Cr(VI) exposure was the induction of prophage-related genes and their encoded products as well as a number of functionally undefined hypothetical genes that were located within the integrated phage regions of the MR-1 genome. In addition, genes with annotated functions in DNA metabolism, cell division, biosynthesis and degradation of the murein (peptidoglycan) sacculus, membrane response, and general environmental stress protection were upregulated, while genes encoding chemotaxis, motility, and transport/binding proteins were largely repressed under conditions of 24-h chromate treatment.

scholarly journals Aerobic Respiration and Its Regulation in the Metal Reducer Shewanella oneidensis

2021 ◽  
Vol 12 ◽  
Author(s):  
Kristen Bertling ◽  
Areen Banerjee ◽  
Daad Saffarini
Keyword(s):  
Carbon Sources ◽  
Shewanella Oneidensis ◽  
Anaerobic Respiration ◽  
Aerobic Respiration ◽  
Wild Type ◽  
Aerobic Growth ◽  
Camp Phosphodiesterase ◽  
Oxidase Gene ◽  
Oxygen Reductase ◽  
Mutant Phenotypes

Shewanella oneidensis MR-1 is a facultative anaerobe known for its ability to reduce metal oxides. Anaerobic respiration, especially metal reduction, has been the subject of extensive research. In contrast, S. oneidensis aerobic respiration has received less attention. S. oneidensis expresses cbb3- and aa3-type cytochrome c oxidases and a bd-type quinol oxidase. The aa3-type oxidase, which in other bacteria is the major oxygen reductase under oxygen replete conditions, does not appear to contribute to aerobic respiration and growth in S. oneidensis. Our results indicated that although the aa3-type oxidase does not play a role in aerobic growth on lactate, the preferred carbon source for S. oneidensis, it is involved in growth on pyruvate or acetate. These results highlight the importance of testing multiple carbon and energy sources when attempting to identify enzyme activities and mutant phenotypes. Several regulatory proteins contribute to the regulation of aerobic growth in S. oneidensis including CRP and ArcA. The 3',5'-cAMP phosphodiesterase (CpdA) appears to play a more significant role in aerobic growth than either CRP or ArcA, yet the deficiency does not appear to be the result of reduced oxidase genes expression. Interestingly, the ∆cpdA mutant was more deficient in aerobic respiration with several carbon sources tested compared to ∆crp, which was moderately deficient only in the presence of lactate. To identify the reason for ∆cpdA aerobic growth deficiency, we isolated a suppressor mutant with transposon insertion in SO_3550. Inactivation of this gene, which encodes an anti-sigma factor, restored aerobic growth in the cpdA mutant to wild-type levels. Inactivation of SO_3550 in wild-type cells, however, did not affect aerobic growth. The S. oneidensis genome encodes two additional CRP-like proteins that we designated CrpB and CrpC. Mutants that lack crpB and crpC were deficient in aerobic growth, but this deficiency was not due to the loss of oxidase gene expression.

Toxic effects of chromium (VI) by maternal ingestion on liver function of female rats and their suckling pups

2011 ◽  
Vol 28 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Nejla Soudani ◽  
Hanen Bouaziz ◽  
Mediha Sefi ◽  
Yassine Chtourou ◽  
Tahia Boudawara ◽  
...  
Keyword(s):  
Liver Function ◽  
Female Rats ◽  
Toxic Effects ◽  
Chromium Vi

scholarly journals The Chromate-Inducible chrBACF Operon from the Transposable Element TnOtChr Confers Resistance to Chromium(VI) and Superoxide

2008 ◽  
Vol 190 (21) ◽  
pp. 6996-7003 ◽  
Author(s):  
Rita Branco ◽  
Ana Paula Chung ◽  
Tatiana Johnston ◽  
Volkan Gurel ◽  
Paula Morais ◽  
...  
Keyword(s):  
Large Scale ◽  
Efflux Pump ◽  
Specific Resistance ◽  
Genetic System ◽  
Aerobic Growth ◽  
Chromium Vi ◽  
Redox Active ◽  
Tetrazolium Staining ◽  
Industrial Use ◽  
Ochrobactrum Tritici

ABSTRACT Large-scale industrial use of chromium(VI) has resulted in widespread contamination with carcinogenic chromium(VI). The abilities of microorganisms to survive in these environments and to detoxify chromate require the presence of specific resistance systems. Here we report identification of the transposon-located (TnOtChr) chromate resistance genes from the highly tolerant strain Ochrobactrum tritici 5bvl1 surviving chromate concentrations of >50 mM. The 7,189-bp-long TnOtChr of the mixed Tn21/Tn3 transposon subfamily contains a group of chrB, chrA, chrC, and chrF genes situated between divergently transcribed resolvase and transposase genes. The chrB and chrA genes, but not chrF or chrC, were essential for establishment of high resistance in chromium-sensitive O. tritici. The chr promoter was strongly induced by chromate or dichromate, but it was completely unresponsive to Cr(III), oxidants, sulfate, or other oxyanions. Plasmid reporter experiments identified ChrB as a chromate-sensing regulator of chr expression. Induction of the chr operon suppressed accumulation of cellular Cr through the activity of a chromate efflux pump encoded by chrA. Expression of chrB, chrC, or chrF in an Escherichia coli sodA sodB double mutant restored its aerobic growth in minimal medium and conferred resistance to superoxide-generating agents menadione and paraquat. Nitroblue tetrazolium staining on native gels showed that ChrC protein had superoxide dismutase activity. TnOtChr appears to represent a mobile genetic system for the distribution of the chromate-regulated resistance operon. The presence of three genes protecting against superoxide toxicity should provide an additional survival advantage to TnOtChr-containing cells in the environments with multiple redox-active contaminants.

scholarly journals Shewanella oneidensisMR-1 Utilizes both Sodium- and Proton-Pumping NADH Dehydrogenases during Aerobic Growth

2018 ◽  
Vol 84 (12) ◽  
Author(s):  
Kody L. Duhl ◽  
Nicholas M. Tefft ◽  
Michaela A. TerAvest
Keyword(s):  
Shewanella Oneidensis ◽  
Growth Yield ◽  
Growth Conditions ◽  
Proton Pumping ◽  
Sodium Ion ◽  
Aerobic Growth ◽  
Content Type ◽  
Growth Defects ◽  
Double Mutant Strain ◽  
Nadh Dehydrogenases

ABSTRACTShewanella oneidensisMR-1 is a metal-reducing bacterium with the ability to utilize many different terminal electron acceptors, including oxygen and solid-metal oxides. Both metal oxide reduction and aerobic respiration have been studied extensively in this organism. However, electron transport chain processes upstream of the terminal oxidoreductases have been relatively understudied in this organism, especially electron transfer from NADH to respiratory quinones. Genome annotation indicates thatS. oneidensisMR-1 encodes four NADH dehydrogenases, a proton-translocating dehydrogenase (Nuo), two sodium ion-translocating dehydrogenases (Nqr1 and Nqr2), and an “uncoupling” dehydrogenase (Ndh), but none of these complexes have been studied. Therefore, we conducted a study specifically focused on the effects of individual NADH dehydrogenase knockouts inS. oneidensisMR-1. We observed that two of the single-mutant strains, the ΔnuoNand ΔnqrF1mutants, exhibited significant growth defects compared with the wild type. However, the defects were minor and only apparent under certain growth conditions. Further testing of the ΔnuoNΔnqrF1double-mutant strain yielded no growth in minimal medium under oxic conditions, indicating that Nuo and Nqr1 have overlapping functions, but at least one is necessary for aerobic growth. Coutilization of proton- and sodium ion-dependent energetics has important implications for the growth of this organism in environments with varied pH and salinity, including microbial electrochemical systems.IMPORTANCEBacteria utilize a wide variety of metabolic pathways that allow them to take advantage of different energy sources, and to do so with varied efficiency. The efficiency of a metabolic process determines the growth yield of an organism, or the amount of biomass it produces per amount of substrate consumed. This parameter has important implications in biotechnology and wastewater treatment, where low growth yields are often preferred to minimize the production of microbial biomass. In this study, we investigated respiratory pathways containing NADH dehydrogenases with varied efficiency (i.e., the number of ions translocated per NADH oxidized) in the metal-reducing bacteriumShewanella oneidensisMR-1. We observed that two different respiratory pathways are used concurrently, and at least one pathway must be functional for growth under oxic conditions.

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