scholarly journals Comparative Analysis of Differentially Expressed Genes in Shewanella oneidensis MR-1 following Exposure to UVC, UVB, and UVA Radiation

2005 ◽  
Vol 187 (10) ◽  
pp. 3556-3564 ◽  
Author(s):  
Xiaoyun Qiu ◽  
George W. Sundin ◽  
Liyou Wu ◽  
Jizhong Zhou ◽  
James M. Tiedje
Keyword(s):  
Uv Radiation ◽  
Short Wavelength ◽  
Cellular Response ◽  
Lethal Factor ◽  
Shewanella Oneidensis ◽  
Uva Irradiation ◽  
Detoxification Mechanism ◽  
Highly Sensitive ◽  
Genes Encoding ◽  
Heavy Metal Efflux

ABSTRACT We previously reported that Shewanella oneidensis MR-1 is highly sensitive to UVC (254 nm), UVB (290 to 320 nm), and UVA (320 to 400 nm). Here we delineated the cellular response of MR-1 to UV radiation damage by analyzing the transcriptional profile during a 1-h recovering period after UVC, UVB, and UVA exposure at a dose that yields about a 20% survival rate. Although the SOS response was observed with all three treatments, the induction was more robust in response to short-wavelength UV radiation (UVB and UVC). Similarly, more prophage-related genes were induced by short-wavelength UV radiation. MR-1 showed an active detoxification mechanism in response to UVA, which included the induction of antioxidant enzymes and iron-sequestering proteins to scavenge reactive oxygen species. In addition, a great number of genes encoding multidrug and heavy metal efflux pumps were induced following UVA irradiation. Our data suggested that activation of prophages appears the major lethal factor in MR-1 following UVC or UVB irradiation, whereas oxidative damage contributes greatly to the high UVA sensitivity in MR-1.

The oxen Gene of Drosophila Encodes a Homolog of Subunit 9 of Yeast Ubiquinol-Cytochrome c Oxidoreductase Complex: Evidence for Modulation of Gene Expression in Response to Mitochondrial Activity

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1727-1736 ◽  
Author(s):  
Maxim V Frolov ◽  
Elizaveta V Benevolenskaya ◽  
James A Birchler
Keyword(s):  
Gene Expression ◽  
Cytochrome C ◽  
Cellular Response ◽  
Insertion Site ◽  
Nuclear Gene ◽  
Mutant Phenotype ◽  
P Element ◽  
Mitochondrial Activity ◽  
Genes Encoding ◽  
Subunit 9

Abstract A P-element insertion in the oxen gene, ox1, has been isolated in a search for modifiers of white gene expression. The mutation preferentially exerts a negative dosage effect upon the expression of three genes encoding ABC transporters involved in pigment precursor transport, white, brown, and scarlet. A precise excision of the P element reverts the mutant phenotype. Five different transcription units were identified around the insertion site. To distinguish a transcript responsible for the mutant phenotype, a set of deletions within the oxen region was generated. Analysis of gene expression within the oxen region in the case of deletions as well as generation of transgenic flies allowed us to identify the transcript responsible for oxen function. It encodes a 6.6-kD homolog of mitochondrial ubiquinol cytochrome c oxidoreductase (QCR9), subunit 9 of the bc1 complex in yeast. In addition to white, brown, and scarlet, oxen regulates the expression of three of seven tested genes. Thus, our data provide additional evidence for a cellular response to changes in mitochondrial function. The oxen mutation provides a model for the genetic analysis in multicellular organisms of the effect of mitochondrial activity on nuclear gene expression.

Thebric à braclocus consists of two paralogous genes encoding BTB/POZ domain proteins and acts as a homeotic and morphogenetic regulator of imaginal development inDrosophila

Development ◽  
2002 ◽  
Vol 129 (10) ◽  
pp. 2419-2433 ◽  
Author(s):  
Jean-Louis Couderc ◽  
Dorothea Godt ◽  
Susan Zollman ◽  
Jiong Chen ◽  
Michelle Li ◽  
...  
Keyword(s):  
Tissue Distribution ◽  
Nuclear Protein ◽  
Drosophila Species ◽  
Sexually Dimorphic ◽  
Conserved Domains ◽  
Gene Dose ◽  
Highly Sensitive ◽  
Genes Encoding ◽  
Redundant Functions ◽  
Related Morphology

The bric à brac (bab) locus acts as a homeotic and morphogenetic regulator in the development of ovaries, appendages and the abdomen. It consists of two structurally and functionally related genes, bab1 and bab2, each of which encodes a single nuclear protein. Bab1 and Bab2 have two conserved domains in common, a BTB/POZ domain and a Psq domain, a motif that characterizes a subfamily of BTB/POZ domain proteins in Drosophila. The tissue distribution of Bab1 and Bab2 overlaps, with Bab1 being expressed in a subpattern of Bab2. Analysis of a series of mutations indicates that the two bab genes have synergistic, distinct and redundant functions during imaginal development. Interestingly, several reproduction-related traits that are sexually dimorphic or show diversity among Drosophila species are highly sensitive to changes in the bab gene dose, suggesting that alterations in bab activity may contribute to evolutionary modification of sex-related morphology.

scholarly journals Differential Contribution of Bacillus anthracis Toxins to Pathogenicity in Two Animal Models

2012 ◽  
Vol 80 (8) ◽  
pp. 2623-2631 ◽  
Author(s):  
Haim Levy ◽  
Shay Weiss ◽  
Zeev Altboum ◽  
Josef Schlomovitz ◽  
Itai Glinert ◽  
...  
Keyword(s):  
Animal Models ◽  
Guinea Pigs ◽  
Protective Antigen ◽  
Comprehensive Evaluation ◽  
Lethal Factor ◽  
Rabbit Model ◽  
Content Type ◽  
Edema Factor ◽  
Genes Encoding ◽  
Guinea Pig Model

ABSTRACTThe virulence ofBacillus anthracis, the causative agent of anthrax, stems from its antiphagocytic capsule, encoded by pXO2, and the tripartite toxins encoded by pXO1. The accepted paradigm states that anthrax is both an invasive and toxinogenic disease and that the toxins play major roles in pathogenicity. We tested this assumption by a systematic study of mutants with combined deletions of thepag,lef, andcyagenes, encoding protective antigen (PA), lethal factor (LF), and edema factor (EF), respectively. The resulting seven mutants (single, double, and triple) were evaluated following subcutaneous (s.c.) and intranasal (i.n.) inoculation in rabbits and guinea pigs. In the rabbit model, virulence is completely dependent on the presence of PA. Any mutant bearing apagdeletion behaved like a pXO1-cured mutant, exhibiting complete loss of virulence with attenuation indices of over 2,500,000 or 1,250 in the s.c. or i.n. route of infection, respectively. In marked contrast, in guinea pigs, deletion ofpagor even of all three toxin components resulted in relatively moderate attenuation, whereas the pXO1-cured bacteria showed complete attenuation. The results indicate that a pXO1-encoded factor(s), other than the toxins, has a major contribution to the virulence mechanism ofB. anthracisin the guinea pig model. These unexpected toxin-dependent and toxin-independent manifestations of pathogenicity in different animal models emphasize the importance and need for a comprehensive evaluation ofB. anthracisvirulence in general and in particular for the design of relevant next-generation anthrax vaccines.

scholarly journals p85α Acts as a Novel Signal Transducer for Mediation of Cellular Apoptotic Response to UV Radiation

2007 ◽  
Vol 27 (7) ◽  
pp. 2713-2731 ◽  
Author(s):  
Lun Song ◽  
Jingxia Li ◽  
Jianping Ye ◽  
Gang Yu ◽  
Jin Ding ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Uv Radiation ◽  
Gene Transcription ◽  
Cell Apoptosis ◽  
Cellular Response ◽  
Nuclear Translocation ◽  
Site Directed Mutagenesis ◽  
Regulatory Subunit ◽  
Special Effect ◽  
Tnf Α

ABSTRACT Apoptosis is an important cellular response to UV radiation (UVR), but the corresponding mechanisms remain largely unknown. Here we report that the p85α regulatory subunit of phosphatidylinositol 3-kinase (PI-3K) exerted a proapoptotic role in response to UVR through the induction of tumor necrosis factor alpha (TNF-α) gene expression. This special effect of p85α was unrelated to the PI-3K-dependent signaling pathway. Further evidence demonstrated that the inducible transcription factor NFAT3 was the major downstream target of p85α for the mediation of UVR-induced apoptosis and TNF-α gene transcription. p85α regulated UVR-induced NFAT3 activation by modulation of its nuclear translocation and DNA binding and the relevant transcriptional activities. Gel shift assays and site-directed mutagenesis allowed the identification of two regions in the TNF-α gene promoter that served as the NFAT3 recognition sequences. Chromatin immunoprecipitation assays further confirmed that the recruitment of NFAT3 to the endogenous TNF-α promoter was regulated by p85α upon UVR exposure. Finally, the knockdown of the NFAT3 level by its specific small interfering RNA decreased UVR-induced TNF-α gene transcription and cell apoptosis. The knockdown of endogenous p85α blocked NFAT activity and TNF-α gene transcription, as well as cell apoptosis. Thus, we demonstrated p85α-associated but PI-3K-independent cell death in response to UVR and identified a novel p85α/NFAT3/TNF-α signaling pathway for the mediation of cellular apoptotic responses under certain stress conditions such as UVR.

scholarly journals UVA Photoprotective Activity of Brown Macroalgae Sargassum cristafolium

Biomedicines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 77 ◽  
Author(s):  
Prasedya ◽  
Syafitri ◽  
Geraldine ◽  
Hamdin ◽  
Frediansyah ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Cell Model ◽  
Positive Control ◽  
Uv Spectra ◽  
Protective Effects ◽  
Negative Effects ◽  
Brown Macroalgae ◽  
Uva Irradiation ◽  
Skin Photoaging

Sunscreens today contain several synthetic UV (Ultraviolet) filter molecules to protect the skin epidermis from UV radiation damage. However, these molecules may create several negative effects on human skin. Due to this condition, there is an increase in the development of natural products to replace uses of these synthetic chemicals. Brown macroalgae Sargassum has been recently studied for its photoprotective activities. The purpose of this study is to investigate photoprotective activity of one of most abundant Sargassum species in Lombok coast; Sargassum cristaefolium. Spectrophotometry analysis with UV-VIS revealed the UV spectra absorbing capability of Sargassum cristaefolium (SC) in the UVA spectrum range (314–400 nm). Furthermore, spectrometry analyses with LC-MS revealed the existence of UV absorbing compound MAA-palythene. In correlation, SC ethanol extracts also demonstrate that it could protect DNA from UVA irradiation as analyzed in vitro in HeLa cell model. The effects of SC on UVA exposed-dorsal mice skin have also shown interesting results, as mice pretreated with SC before UVA exposure showed protective activity on the epidermal integrity similar as positive control. Whereas, UV exposed mice without SC or commercial products resulted in increased epidermal thickness, which is the common parameter of skin photoaging. In addition, pretreated mice with SC also show protective effects in the formation of collagen connective tissues. Overall, current results show promising photoprotective activity of SC against UV radiation. More advanced investigations of SC as a potential photoprotective agent would be reasonable for development of macroalgae-based natural skin protection products.

scholarly journals Differential Gene Expression in Response to Hydrogen Peroxide and the Putative PerR Regulon of Synechocystis sp. Strain PCC 6803

2004 ◽  
Vol 186 (11) ◽  
pp. 3331-3345 ◽  
Author(s):  
Hong Li ◽  
Abhay K. Singh ◽  
Lauren M. McIntyre ◽  
Louis A. Sherman
Keyword(s):  
Chlorophyll Biosynthesis ◽  
Short Term ◽  
Histidine Kinases ◽  
Highly Sensitive ◽  
Number Of Genes ◽  
Genes Encoding ◽  
Differential Gene ◽  
Regulatory Properties ◽  
Knockout Mutation ◽  
Pcc 6803

ABSTRACT We utilized a full genome cDNA microarray to identify the genes that comprise the peroxide stimulon in the cyanobacterium Synechocystis sp. strain PCC 6803. We determined that a gene (slr1738) encoding a protein similar to PerR in Bacillus subtilis was induced by peroxide. We constructed a PerR knockout strain and used it to help identify components of the PerR regulon, and we found that the regulatory properties were consistent with the hypothesis that PerR functions as a repressor. This effort was guided by finding putative PerR boxes in positions upstream of specific genes and by careful statistical analysis. PerR and sll1621 (ahpC), which codes for a peroxiredoxin, share a divergent promoter that is regulated by PerR. We found that isiA, encoding a Chl protein that is induced under low-iron conditions, was strongly induced by a short-term peroxide stress. Other genes that were strongly induced by peroxide included sigD, sigB, and genes encoding peroxiredoxins and Dsb-like proteins that have not been studied yet in this strain. A gene (slr1894) that encoded a protein similar to MrgA in B. subtilis was upregulated by peroxide, and a strain containing an mrgA knockout mutation was highly sensitive to peroxide. A number of genes were downregulated, including key genes in the chlorophyll biosynthesis pathway and numerous regulatory genes, including those encoding histidine kinases. We used PerR mutants and a thioredoxin mutant (TrxA1) to study differential expression in response to peroxide and determined that neither PerR nor TrxA1 is essential for the peroxide protective response.

scholarly journals Myosin IIB assembly state determines its mechanosensitive dynamics

2019 ◽  
Vol 218 (3) ◽  
pp. 895-908 ◽  
Author(s):  
Eric S. Schiffhauer ◽  
Yixin Ren ◽  
Vicente A. Iglesias ◽  
Priyanka Kothari ◽  
Pablo A. Iglesias ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Cell Shape ◽  
Cellular Response ◽  
Myosin Ii ◽  
3T3 Cells ◽  
Dictyostelium Myosin ◽  
Highly Sensitive ◽  
Key Players ◽  
Nih 3T3 ◽  
Shape Changes

Dynamical cell shape changes require a highly sensitive cellular system that can respond to chemical and mechanical inputs. Myosin IIs are key players in the cell’s ability to react to mechanical inputs, demonstrating an ability to accumulate in response to applied stress. Here, we show that inputs that influence the ability of myosin II to assemble into filaments impact the ability of myosin to respond to stress in a predictable manner. Using mathematical modeling for Dictyostelium myosin II, we predict that myosin II mechanoresponsiveness will be biphasic with an optimum established by the percentage of myosin II assembled into bipolar filaments. In HeLa and NIH 3T3 cells, heavy chain phosphorylation of NMIIB by PKCζ, as well as expression of NMIIA, can control the ability of NMIIB to mechanorespond by influencing its assembly state. These data demonstrate that multiple inputs to the myosin II assembly state integrate at the level of myosin II to govern the cellular response to mechanical inputs.

scholarly journals Purification and Characterization of the [NiFe]-Hydrogenase of Shewanella oneidensis MR-1

2011 ◽  
Vol 77 (16) ◽  
pp. 5584-5590 ◽  
Author(s):  
Liang Shi ◽  
Sara M. Belchik ◽  
Andrew E. Plymale ◽  
Steve Heald ◽  
Alice C. Dohnalkova ◽  
...  
Keyword(s):  
Methyl Viologen ◽  
Shewanella Oneidensis ◽  
Tris Buffer ◽  
Transmission Electron Microscopy Analysis ◽  
Content Type ◽  
X Ray ◽  
Hepes Buffer ◽  
Transmission Electron ◽  
Genes Encoding ◽  
Electron Microscopy Analysis

ABSTRACTShewanella oneidensisMR-1 possesses a periplasmic [NiFe]-hydrogenase (MR-1 [NiFe]-H2ase) that has been implicated in H2production and oxidation as well as technetium [Tc(VII)] reduction. To characterize the roles of MR-1 [NiFe]-H2ase in these proposed reactions, the genes encoding both subunits of MR-1 [NiFe]-H2ase were cloned and then expressed in an MR-1 mutant withouthyaBandhydAgenes. Expression of recombinant MR-1 [NiFe]-H2ase intransrestored the mutant's ability to produce H2at 37% of that for the wild type. Following purification, MR-1 [NiFe]-H2ase coupled H2oxidation to reduction of Tc(VII)O4−and methyl viologen. Change of the buffers used affected MR-1 [NiFe]-H2ase-mediated reduction of Tc(VII)O4−but not methyl viologen. Under the conditions tested, all Tc(VII)O4−used was reduced in Tris buffer, while in HEPES buffer, only 20% of Tc(VII)O4−was reduced. The reduced products were soluble in Tris buffer but insoluble in HEPES buffer. Transmission electron microscopy analysis revealed that Tc precipitates reduced in HEPES buffer were aggregates of crystallites with diameters of ∼5 nm. Measurements with X-ray absorption near-edge spectroscopy revealed that the reduction products were a mixture of Tc(IV) and Tc(V) in Tris buffer but only Tc(IV) in HEPES buffer. Measurements with extended X-ray adsorption fine structure showed that while the Tc bonding environment in Tris buffer could not be determined, the Tc(IV) product in HEPES buffer was very similar to Tc(IV)O2·nH2O, which was also the product of Tc(VII)O4−reduction by MR-1 cells. These results shows for the first time that MR-1 [NiFe]-H2ase catalyzes Tc(VII)O4−reduction directly by coupling to H2oxidation.

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.

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