scholarly journals Transcription of IVIAT and Virulence Genes in Photobacterium damselae subsp. piscicida Infecting Solea senegalensis

2018 ◽  
Vol 6 (3) ◽  
pp. 67 ◽  
Author(s):  
José Núñez-Díaz ◽  
Milena Fumanal ◽  
Ana do Vale ◽  
Catalina Fernández-Díaz ◽  
Miguel Moriñigo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Iron Acquisition ◽  
Disease Outbreaks ◽  
Head Kidney ◽  
Solea Senegalensis ◽  
Marine Aquaculture ◽  
Environmental Signals ◽  
Genes Encoding ◽  
Photobacterium Damselae

Photobacterium damselae subsp. piscicida (Phdp) is responsible for disease outbreaks in marine aquaculture worldwide. Solea senegalensis, a valuable fish species for aquaculture in the south of Europe, is frequently affected by this pathogen. It is well established that bacteria respond to environmental signals and, in the case of pathogens, this ability may determine the outcome of their interaction with the host. Determination of gene expression under in vivo conditions constitutes a valuable tool in the assessment of microbial pathogenesis. Considering that different hosts may represent different environments for the pathogen, expression of Phdp virulence and in vivo induced antigen (IVIAT) genes during S. senegalensis infection has been determined in the present work. Increased transcription of genes encoding proteins involved in iron acquisition (Irp1, Irp2, HutB and HutD), oxidative stress defence (AhpC and Sod), adhesion (PDP_0080), toxins (AIP56) and metabolism (Impdh, Shmt and AlaRS) were detected in Phdp infecting S. senegalensis head kidney or liver. The highest increases corresponded to genes involved in survival under iron limiting conditions and oxidative stress, indicating their essential role during infection of sole. Results obtained give insight into Phdp virulence strategies and contribute to the identification of promising targets for the control of photobacteriosis.

scholarly journals Genome-Wide Screen of Salmonella Genes Expressed during Infection in Pigs, Using In Vivo Expression Technology

2007 ◽  
Vol 73 (23) ◽  
pp. 7522-7530 ◽  
Author(s):  
Yanyan Huang ◽  
Christopher L. Leming ◽  
Mitsu Suyemoto ◽  
Craig Altier
Keyword(s):  
Genomic Library ◽  
Clinical Signs ◽  
Great Majority ◽  
Dna Fragments ◽  
Environmental Signals ◽  
Genome Wide ◽  
Serovar Typhimurium ◽  
Genes Encoding ◽  
Elevated Expression

ABSTRACT Pigs are a food-producing species that readily carry Salmonella but, in the great majority of cases, do not show clinical signs of disease. Little is known about the functions required by Salmonella to be maintained in pigs. We have devised a recombinase-based promoter-trapping strategy to identify genes with elevated expression during pig infection with Salmonella enterica serovar Typhimurium. A total of 55 clones with in vivo-induced promoters were selected from a genomic library of ∼10,000 random Salmonella DNA fragments fused to the recombinase cre, and the cloned DNA fragments were analyzed by sequencing. Thirty-one genes encoding proteins involved in bacterial adhesion and colonization (including bcfA, hscA, rffG, and yciR), virulence (metL), heat shock (hscA), and a sensor of a two-component regulator (hydH) were identified. Among the 55 clones, 19 were isolated from both the tonsils and the intestine, while 23 were identified only in the intestine and 13 only in tonsils. High temperature and increased osmolarity were identified as environmental signals that induced in vivo-expressed genes, suggesting possible signals for expression.

scholarly journals Oxidative Stress Sensor Keap1 Functions as an Adaptor for Cul3-Based E3 Ligase To Regulate Proteasomal Degradation of Nrf2

2004 ◽  
Vol 24 (16) ◽  
pp. 7130-7139 ◽  
Author(s):  
Akira Kobayashi ◽  
Moon-Il Kang ◽  
Hiromi Okawa ◽  
Makiko Ohtsuji ◽  
Yukari Zenke ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Proteins ◽  
E3 Ligase ◽  
Genes Encoding ◽  
Cullin 3 ◽  
Ubiquitin Proteasome ◽  
A Subunit ◽  
Antioxidant Stress ◽  
And Oxidative Stress

ABSTRACT Transcription factor Nrf2 is a major regulator of genes encoding phase 2 detoxifying enzymes and antioxidant stress proteins in response to electrophilic agents and oxidative stress. In the absence of such stimuli, Nrf2 is inactive owing to its cytoplasmic retention by Keap1 and rapid degradation through the proteasome system. We examined the contribution of Keap1 to the rapid turnover of Nrf2 (half-life of less than 20 min) and found that a direct association between Keap1 and Nrf2 is required for Nrf2 degradation. In a series of domain function analyses of Keap1, we found that both the BTB and intervening-region (IVR) domains are crucial for Nrf2 degradation, implying that these two domains act to recruit ubiquitin-proteasome factors. Indeed, Cullin 3 (Cul3), a subunit of the E3 ligase complex, was found to interact specifically with Keap1 in vivo. Keap1 associates with the N-terminal region of Cul3 through the IVR domain and promotes the ubiquitination of Nrf2 in cooperation with the Cul3-Roc1 complex. These results thus provide solid evidence that Keap1 functions as an adaptor of Cul3-based E3 ligase. To our knowledge, Nrf2 and Keap1 are the first reported mammalian substrate and adaptor, respectively, of the Cul3-based E3 ligase system.

scholarly journals Identification of Specific In Vivo-Induced (ivi) Genes in Yersinia ruckeri and Analysis of Ruckerbactin, a Catecholate Siderophore Iron Acquisition System

2004 ◽  
Vol 70 (9) ◽  
pp. 5199-5207 ◽  
Author(s):  
L. Fernández ◽  
I. Márquez ◽  
J. A. Guijarro
Keyword(s):  
Iron Acquisition ◽  
Lethal Dose ◽  
Yersinia Ruckeri ◽  
Secretion Systems ◽  
Regulation Of Expression ◽  
Significant Similarity ◽  
Technology System ◽  
Type Iv ◽  
Genes Encoding

ABSTRACT This work reports the utilization of an in vivo expression technology system to identify in vivo-induced (ivi) genes in Yersinia ruckeri after determination of the conditions needed for its selection in fish. Fourteen clones were selected, and the cloned DNA fragments were analyzed after partial sequencing. In addition to sequences with no significant similarity, homology with genes encoding proteins putatively involved in two-component and type IV secretion systems, adherence, specific metabolic functions, and others were found. Among these sequences, four were involved in iron acquisition through a catechol siderophore (ruckerbactin). Thus, unlike other pathogenic yersiniae producing yersiniabactin, Y. ruckeri might be able to produce and utilize only this phenolate. The genetic organization of the ruckerbactin biosynthetic and uptake loci was similar to that of the Escherichia coli enterobactin gene cluster. Genes rucC and rupG, putative counterparts of E. coli entC and fepG, respectively, involved in the biosynthesis and transport of the iron siderophore complex, respectively, were analyzed further. Thus, regulation of expression by iron and temperature and their presence in other Y. ruckeri siderophore-producing strains were confirmed for these two loci. Moreover, 50% lethal dose values 100-fold higher than those of the wild-type strain were obtained with the rucC isogenic mutant, showing the importance of ruckerbactin in the pathogenesis caused by this microorganism.

scholarly journals The soxRS response of Escherichia coli can be induced in the absence of oxidative stress and oxygen by modulation of NADPH content

Microbiology ◽  
2011 ◽  
Vol 157 (4) ◽  
pp. 957-965 ◽  
Author(s):  
Adriana R. Krapp ◽  
María Victoria Humbert ◽  
Néstor Carrillo
Keyword(s):  
Oxidative Stress ◽  
Escherichia Coli ◽  
Methyl Viologen ◽  
Transcriptional Regulator ◽  
E Coli ◽  
Enhanced Sensitivity ◽  
Genes Encoding ◽  
Cellular Signal ◽  
Redox Shuttle

The soxRS regulon protects Escherichia coli cells against superoxide and nitric oxide. Oxidation of the SoxR sensor, a [2Fe–2S]-containing transcriptional regulator, triggers the response, but the nature of the cellular signal sensed by SoxR is still a matter of debate. In vivo, the sensor is maintained in a reduced, inactive state by the activities of SoxR reductases, which employ NADPH as an electron donor. The hypothesis that NADPH levels affect deployment of the soxRS response was tested by transforming E. coli cells with genes encoding enzymes and proteins that lead to either build-up or depletion of the cellular NADPH pool. Introduction of NADP+-reducing enzymes, such as wheat non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase or E. coli malic enzyme, led to NADPH accumulation, inhibition of the soxRS regulon and enhanced sensitivity to the superoxide propagator methyl viologen (MV). Conversely, expression of pea ferredoxin (Fd), a redox shuttle that can oxidize NADPH via ferredoxin-NADP(H) reductase, resulted in execution of the soxRS response in the absence of oxidative stress, and in higher tolerance to MV. Processes that caused NADPH decline, including oxidative stress and Fd activity, correlated with an increase in total (NADP++NADPH) stocks. SoxS expression can be induced by Fd expression or by MV in anaerobiosis, under conditions in which NADPH is oxidized but no superoxide can be formed. The results indicate that activation of the soxRS regulon in E. coli cells exposed to superoxide-propagating compounds can be triggered by depletion of the NADPH stock rather than accumulation of superoxide itself. They also suggest that bacteria need to finely regulate homeostasis of the NADP(H) pool to enable proper deployment of this defensive response.

scholarly journals The Role of PerR in O2-Affected Gene Expression of Clostridium acetobutylicum

2009 ◽  
Vol 191 (19) ◽  
pp. 6082-6093 ◽  
Author(s):  
Falk Hillmann ◽  
Christina Döring ◽  
Oliver Riebe ◽  
Armin Ehrenreich ◽  
Ralf-Jörg Fischer ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Clostridium Acetobutylicum ◽  
Wild Type ◽  
Gene Encoding ◽  
Homologous Protein ◽  
Strict Anaerobe ◽  
Genes Encoding ◽  
Highly Expressed Genes

ABSTRACT In the strict anaerobe Clostridium acetobutylicum, a PerR-homologous protein has recently been identified as being a key repressor of a reductive machinery for the scavenging of reactive oxygen species and molecular O2. In the absence of PerR, the full derepression of its regulon resulted in increased resistance to oxidative stress and nearly full tolerance of an aerobic environment. In the present study, the complementation of a Bacillus subtilis PerR mutant confirmed that the homologous protein from C. acetobutylicum acts as a functional peroxide sensor in vivo. Furthermore, we used a transcriptomic approach to analyze gene expression in the aerotolerant PerR mutant strain and compared it to the O2 stimulon of wild-type C. acetobutylicum. The genes encoding the components of the alternative detoxification system were PerR regulated. Only few other targets of direct PerR regulation were identified, including two highly expressed genes encoding enzymes that are putatively involved in the central energy metabolism. All of them were highly induced when wild-type cells were exposed to sublethal levels of O2. Under these conditions, C. acetobutylicum also activated the repair and biogenesis of DNA and Fe-S clusters as well as the transcription of a gene encoding an unknown CO dehydrogenase-like enzyme. Surprisingly few genes were downregulated when exposed to O2, including those involved in butyrate formation. In summary, these results show that the defense of this strict anaerobe against oxidative stress is robust and by far not limited to the removal of O2 and its reactive derivatives.

scholarly journals Regulation of High-Affinity Iron Acquisition Homologues in the Tsetse Fly Symbiont Sodalis glossinidius

2010 ◽  
Vol 192 (14) ◽  
pp. 3780-3787 ◽  
Author(s):  
Laura J. Runyen-Janecky ◽  
Alexandria N. Brown ◽  
Brittany Ott ◽  
Haddis G. Tujuba ◽  
Rita V. M. Rio
Keyword(s):  
Iron Acquisition ◽  
Shigella Flexneri ◽  
Tsetse Fly ◽  
E Coli ◽  
High Affinity ◽  
Sodalis Glossinidius ◽  
Reverse Transcription Pcr ◽  
Genes Encoding ◽  
Iron Manganese

ABSTRACT Sodalis glossinidius is a facultative intracellular bacterium that is a secondary symbiont of the tsetse fly (Diptera: Glossinidae). Since studies with other facultative intracellular bacteria have shown that high-affinity iron acquisition genes are upregulated in vivo, we investigated the regulation of several Sodalis genes that encode putative iron acquisition systems. These genes, SG1538 (hemT) and SG1516 (sitA), are homologous to genes encoding periplasmic heme and iron/manganese transporters, respectively. hemT promoter- and sitA promoter-gfp fusions were constructed, and in both Escherichia coli and Sodalis backgrounds, expression levels of these fusions were higher when the bacteria were grown in iron-limiting media than when the bacteria were grown in iron-replete media. The Sodalis promoters were tested for iron regulation in an E. coli strain that lacks the fur gene, which encodes the iron-responsive transcriptional repressor Fur. Expression of the promoter-gfp fusions in the E. coli fur mutant was constitutively high in both iron-replete and iron-deplete media, and addition of either Shigella flexneri fur or Sodalis fur to a plasmid restored normal regulation. A Sodalis fur mutant was constructed by intron mutagenesis, and semiquantitative reverse transcription-PCR (RT-PCR) showed that iron repression of sitA expression was also abolished in this strain. In vivo expression analysis showed that hemT and sitA are expressed when Sodalis is within tsetse fly hosts, suggesting a biological role for these genes when Sodalis is within the tsetse fly.

scholarly journals HrrSA orchestrates a systemic response to heme and determines prioritization of terminal cytochrome oxidase expression

2020 ◽  
Vol 48 (12) ◽  
pp. 6547-6562
Author(s):  
Marc Keppel ◽  
Max Hünnefeld ◽  
Andrei Filipchyk ◽  
Ulrike Viets ◽  
Cedric-Farhad Davoudi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Response Regulator ◽  
Cell Envelope ◽  
Affinity Purification ◽  
Network Evolution ◽  
Dynamic Binding ◽  
Prosthetic Group ◽  
Time Resolved ◽  
Genes Encoding

Abstract Heme is a multifaceted molecule. While serving as a prosthetic group for many important proteins, elevated levels are toxic to cells. The complexity of this stimulus has shaped bacterial network evolution. However, only a small number of targets controlled by heme-responsive regulators have been described to date. Here, we performed chromatin affinity purification and sequencing to provide genome-wide insights into in vivo promoter occupancy of HrrA, the response regulator of the heme-regulated two-component system HrrSA of Corynebacterium glutamicum. Time-resolved profiling revealed dynamic binding of HrrA to more than 200 different genomic targets encoding proteins associated with heme biosynthesis, the respiratory chain, oxidative stress response and cell envelope remodeling. By repression of the extracytoplasmic function sigma factor sigC, which activates the cydABCD operon, HrrA prioritizes the expression of genes encoding the cytochrome bc1-aa3 supercomplex. This is also reflected by a significantly decreased activity of the cytochrome aa3 oxidase in the ΔhrrA mutant. Furthermore, our data reveal that HrrA also integrates the response to heme-induced oxidative stress by activating katA encoding the catalase. These data provide detailed insights in the systemic strategy that bacteria have evolved to respond to the versatile signaling molecule heme.

Glial cytotoxicity of low doses of cadmium as a model of heavy metal pollution influence on vertebrates

2020 ◽  
Vol 31 (1) ◽  
pp. 3-10
Author(s):  
V. S. Nedzvetsky ◽  
V. Ya. Gasso ◽  
A. M. Hahut ◽  
I. A. Hasso
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Oxidative Damage ◽  
Cadmium Chloride ◽  
Glioma Cells ◽  
Low Doses ◽  
Genotoxic Effects ◽  
Cadmium Ions

Cadmium is a common transition metal that entails an extremely wide range of toxic effects in humans and animals. The cytotoxicity of cadmium ions and its compounds is due to various genotoxic effects, including both DNA damage and chromosomal aberrations. Some bone diseases, kidney and digestive system diseases are determined as pathologies that are closely associated with cadmium intoxication. In addition, cadmium is included in the list of carcinogens because of its ability to initiate the development of tumors of several forms of cancer under conditions of chronic or acute intoxication. Despite many studies of the effects of cadmium in animal models and cohorts of patients, in which cadmium effects has occurred, its molecular mechanisms of action are not fully understood. The genotoxic effects of cadmium and the induction of programmed cell death have attracted the attention of researchers in the last decade. In recent years, the results obtained for in vivo and in vitro experimental models have shown extremely high cytotoxicity of sublethal concentrations of cadmium and its compounds in various tissues. One of the most studied causes of cadmium cytotoxicity is the development of oxidative stress and associated oxidative damage to macromolecules of lipids, proteins and nucleic acids. Brain cells are most sensitive to oxidative damage and can be a critical target of cadmium cytotoxicity. Thus, oxidative damage caused by cadmium can initiate genotoxicity, programmed cell death and inhibit their viability in the human and animal brains. To test our hypothesis, cadmium cytotoxicity was assessed in vivo in U251 glioma cells through viability determinants and markers of oxidative stress and apoptosis. The result of the cell viability analysis showed the dose-dependent action of cadmium chloride in glioma cells, as well as the generation of oxidative stress (p <0.05). Calculated for 48 hours of exposure, the LD50 was 3.1 μg×ml-1. The rates of apoptotic death of glioma cells also progressively increased depending on the dose of cadmium ions. A high correlation between cadmium concentration and apoptotic response (p <0.01) was found for cells exposed to 3–4 μg×ml-1 cadmium chloride. Moreover, a significant correlation was found between oxidative stress (lipid peroxidation) and induction of apoptosis. The results indicate a strong relationship between the generation of oxidative damage by macromolecules and the initiation of programmed cell death in glial cells under conditions of low doses of cadmium chloride. The presented results show that cadmium ions can induce oxidative damage in brain cells and inhibit their viability through the induction of programmed death. Such effects of cadmium intoxication can be considered as a model of the impact of heavy metal pollution on vertebrates.

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