Oxygen sensing strategies in mammals and bacteria

Taabazuing, Cornelius Y.; Knapp, Michael J.

doi:10.1016/j.jinorgbio.2013.12.010

Cited by 46 publications

(38 citation statements)

References 154 publications

(201 reference statements)

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“…These results indicate that the Hr protein may act as an oxygen biosensor to reprogram transcription to adapt to the harsh internal environment of the phagocyte. This is consistent with the results of recent research that showed that Hr-like proteins are emerging as O 2 and iron sensors in both bacteria and humans (Taabazuing et al, 2014). For example, the methyl-accepting chemotaxis protein from Desulfovibrio vulgaris, DcrH-Hr, contains an Hr domain that acts as an oxygen sensor (Isaza et al, 2006).…”

Section: Discussionsupporting

confidence: 91%

Hemerythrin is required for Aeromonas hydraphlia to survive in the macrophages of Anguilla japonica

et al. 2016

Genet. Mol. Res.

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ABSTRACT. Survival in host phagocytes is an effective strategy for pathogenic microbes to spread. To understand the mechanisms of Aeromonas hydrophila survival within host macrophages, a library of mini-Tn10 transposon insertion mutants was constructed. The M85 mutant, whose survival in host macrophages was only 23.1% of that of the wild-type (WT) strain, was utilized for further study. Molecular analysis showed that a 756-bp open reading frame (ORF) (GenBank accession No. CP007576) in the M85 mutant was interrupted by miniTn10. This ORF encodes for a 183-amino acid protein and displays the highest sequence identity (99%) with the hemerythrin (Hr) protein of A. hydrophila subspecies hydrophila ATCC 7966. The survival of the WT, M85 mutant, and complemented M85 (Hr) strains were compared in host macrophages in vitro, and the results showed that M85 exhibited defective survival, while that of M85 (Hr) was restored. To investigate the possible mechanisms of A. hydrophila survival in host macrophages, the expression of Hr under hyperoxic and hypoxic conditions was evaluated. The results revealed that the expression of this protein was higher under hyperoxic conditions than under hypoxic conditions, which indicates that Hr protein expression is sensitive to O 2 concentration. Hydrogen peroxide sensitivity tests further suggested that the M85 mutant was more sensitive to oxidative stress than the WT and M85 (Hr) strains. Taken together, these results suggest that the Hr protein may act as an O 2 sensor and as a detoxifier of reactive oxygen species, and is required for A. hydrophila survival within host macrophages.

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Section: Discussionsupporting

confidence: 91%

Hemerythrin is required for Aeromonas hydraphlia to survive in the macrophages of Anguilla japonica

et al. 2016

Genet. Mol. Res.

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“…marinus strain MC-1 (35 % identity) whereas two are more similar to predicted proteins from non-MTB (ORF 02806: Treponema brennaborense, 35 % identity; ORF 02812: Spirochaeta thermophile, 34 % identity). Because hemerythrin is a protein involved in oxygen transfer, chemotaxis and signal transduction [46, 50], the hemerythrin that is common to Mf. australis strain IT-1 and Mc.…”

Section: Resultsmentioning

confidence: 99%

Combined genomic and structural analyses of a cultured magnetotactic bacterium reveals its niche adaptation to a dynamic environment

et al. 2016

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BackgroundMagnetotactic bacteria (MTB) are a unique group of prokaryotes that have a potentially high impact on global geochemical cycling of significant primary elements because of their metabolic plasticity and the ability to biomineralize iron-rich magnetic particles called magnetosomes. Understanding the genetic composition of the few cultivated MTB along with the unique morphological features of this group of bacteria may provide an important framework for discerning their potential biogeochemical roles in natural environments.ResultsGenomic and ultrastructural analyses were combined to characterize the cultivated magnetotactic coccus Magnetofaba australis strain IT-1. Cells of this species synthesize a single chain of elongated, cuboctahedral magnetite (Fe3O4) magnetosomes that cause them to align along magnetic field lines while they swim being propelled by two bundles of flagella at velocities up to 300 μm s−1. High-speed microscopy imaging showed the cells move in a straight line rather than in the helical trajectory described for other magnetotactic cocci. Specific genes within the genome of Mf. australis strain IT-1 suggest the strain is capable of nitrogen fixation, sulfur reduction and oxidation, synthesis of intracellular polyphosphate granules and transporting iron with low and high affinity. Mf. australis strain IT-1 and Magnetococcus marinus strain MC-1 are closely related phylogenetically although similarity values between their homologous proteins are not very high.Conclusion Mf. australis strain IT-1 inhabits a constantly changing environment and its complete genome sequence reveals a great metabolic plasticity to deal with these changes. Aside from its chemoautotrophic and chemoheterotrophic metabolism, genomic data indicate the cells are capable of nitrogen fixation, possess high and low affinity iron transporters, and might be capable of reducing and oxidizing a number of sulfur compounds. The relatively large number of genes encoding transporters as well as chemotaxis receptors in the genome of Mf. australis strain IT-1 combined with its rapid swimming velocities, indicate that cells respond rapidly to environmental changes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3064-9) contains supplementary material, which is available to authorized users.

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“…Number of positive staining patients is therefore not relevant. 5 Presented numbers are odds-ratios for 2-year locoregional recurrence, not hazard ratios. 6 Last surviving patient was scored as deceased to enable HR-calculation, because of 100% survival in one arm.…”

Section: Other Treatment Strategiesmentioning

confidence: 99%

Clinical implications of hypoxia biomarker expression in head and neck squamous cell carcinoma: a systematic review

et al. 2015

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Awareness increases that the tumor biology influences treatment outcome and prognosis in cancer. Tumor hypoxia is thought to decrease sensitivity to radiotherapy and some forms of chemotherapy. Presence of hypoxia may be assessed by investigating expression of endogenous markers of hypoxia (EMH) using immunohistochemistry (IHC). In this systematic review we investigated the effect of EMH expression on local control and survival according to treatment modality in head and neck cancer (head and neck squamous cell carcinoma [HNSCC]). A search was performed in MEDLINE and EMBASE. Studies were eligible for inclusion that described EMH expression in relation to outcome in HNSCC patients. Quality was assessed using the Quality in Prognosis Studies (QUIPS) tool. Hazard ratios for locoregional control and survival were extracted. Forty studies of adequate quality were included. HIF-1a, HIF-2a, CA-IX, GLUT-1, and OPN were identified as the best described EMHs. With exception of HIF-2a, all EMHs were significantly related to adverse outcome in multiple studies, especially in studies where patients underwent single-modality treatment. Positive expression was often correlated with adverse clinical characteristics, including disease stage and differentiation grade. In summary, EMH expression was common in HNSCC patients and negatively influenced their prognosis. Future studies should investigate the effect of hypoxia-modified treatment schedules in patients with high In summary, EMH expression. These may include ARCON, treatment with nimorazole, or novel targeted therapies directed at hypoxic tissue. Also, the feasibility of surgical removal of the hypoxic tumor volume prior to radiotherapy should be investigated.

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Oxygen sensing strategies in mammals and bacteria

Cited by 46 publications

References 154 publications

Hemerythrin is required for Aeromonas hydraphlia to survive in the macrophages of Anguilla japonica

Hemerythrin is required for Aeromonas hydraphlia to survive in the macrophages of Anguilla japonica

Combined genomic and structural analyses of a cultured magnetotactic bacterium reveals its niche adaptation to a dynamic environment

Clinical implications of hypoxia biomarker expression in head and neck squamous cell carcinoma: a systematic review

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