Quinolone Resistance Reversion by Targeting the SOS Response

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E. Recacha

2017-10-01

Full Text Available Suppression of the SOS response has been postulated as a therapeutic strategy for potentiating antimicrobial agents. We aimed to evaluate the impact of its suppression on reversing resistance using a model of isogenic strains of Escherichia coli representing multiple levels of quinolone resistance. E. coli mutants exhibiting a spectrum of SOS activity were constructed from isogenic strains carrying quinolone resistance mechanisms with susceptible and resistant phenotypes. Changes in susceptibility were evaluated by static (MICs and dynamic (killing curves or flow cytometry methodologies. A peritoneal sepsis murine model was used to evaluate in vivo impact. Suppression of the SOS response was capable of resensitizing mutant strains with genes encoding three or four different resistance mechanisms (up to 15-fold reductions in MICs. Killing curve assays showed a clear disadvantage for survival (Δlog10 CFU per milliliter [CFU/ml] of 8 log units after 24 h, and the in vivo efficacy of ciprofloxacin was significantly enhanced (Δlog10 CFU/g of 1.76 log units in resistant strains with a suppressed SOS response. This effect was evident even after short periods (60 min of exposure. Suppression of the SOS response reverses antimicrobial resistance across a range of E. coli phenotypes from reduced susceptibility to highly resistant, playing a significant role in increasing the in vivo efficacy.

The SbSOS1 gene from the extreme halophyte Salicornia brachiata enhances Na(+) loading in xylem and confers salt tolerance in transgenic tobacco.

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Yadav, Narendra Singh; Shukla, Pushp Sheel; Jha, Anupama; Agarwal, Pradeep K; Jha, Bhavanath

2012-10-11

Soil salinity adversely affects plant growth and development and disturbs intracellular ion homeostasis resulting cellular toxicity. The Salt Overly Sensitive 1 (SOS1) gene encodes a plasma membrane Na(+)/H(+) antiporter that plays an important role in imparting salt stress tolerance to plants. Here, we report the cloning and characterisation of the SbSOS1 gene from Salicornia brachiata, an extreme halophyte. The SbSOS1 gene is 3774 bp long and encodes a protein of 1159 amino acids. SbSOS1 exhibited a greater level of constitutive expression in roots than in shoots and was further increased by salt stress. Overexpressing the S. brachiata SbSOS1 gene in tobacco conferred high salt tolerance, promoted seed germination and increased root length, shoot length, leaf area, fresh weight, dry weight, relative water content (RWC), chlorophyll, K(+)/Na(+) ratio, membrane stability index, soluble sugar, proline and amino acid content relative to wild type (WT) plants. Transgenic plants exhibited reductions in electrolyte leakage, reactive oxygen species (ROS) and MDA content in response to salt stress, which probably occurred because of reduced cytosolic Na(+) content and oxidative damage. At higher salt stress, transgenic tobacco plants exhibited reduced Na(+) content in root and leaf and higher concentrations in stem and xylem sap relative to WT, which suggests a role of SbSOS1 in Na(+) loading to xylem from root and leaf tissues. Transgenic lines also showed increased K(+) and Ca(2+) content in root tissue compared to WT, which reflect that SbSOS1 indirectly affects the other transporters activity. Overexpression of SbSOS1 in tobacco conferred a high degree of salt tolerance, enhanced plant growth and altered physiological and biochemical parameters in response to salt stress. In addition to Na(+) efflux outside the plasma membrane, SbSOS1 also helps to maintain variable Na(+) content in different organs and also affect the other transporters activity indirectly. These

Quinolone Resistance Reversion by Targeting the SOS Response.

Science.gov (United States)

Recacha, E; Machuca, J; Díaz de Alba, P; Ramos-Güelfo, M; Docobo-Pérez, F; Rodriguez-Beltrán, J; Blázquez, J; Pascual, A; Rodríguez-Martínez, J M

2017-10-10

Suppression of the SOS response has been postulated as a therapeutic strategy for potentiating antimicrobial agents. We aimed to evaluate the impact of its suppression on reversing resistance using a model of isogenic strains of Escherichia coli representing multiple levels of quinolone resistance. E. coli mutants exhibiting a spectrum of SOS activity were constructed from isogenic strains carrying quinolone resistance mechanisms with susceptible and resistant phenotypes. Changes in susceptibility were evaluated by static (MICs) and dynamic (killing curves or flow cytometry) methodologies. A peritoneal sepsis murine model was used to evaluate in vivo impact. Suppression of the SOS response was capable of resensitizing mutant strains with genes encoding three or four different resistance mechanisms (up to 15-fold reductions in MICs). Killing curve assays showed a clear disadvantage for survival (Δlog 10 CFU per milliliter [CFU/ml] of 8 log units after 24 h), and the in vivo efficacy of ciprofloxacin was significantly enhanced (Δlog 10 CFU/g of 1.76 log units) in resistant strains with a suppressed SOS response. This effect was evident even after short periods (60 min) of exposure. Suppression of the SOS response reverses antimicrobial resistance across a range of E. coli phenotypes from reduced susceptibility to highly resistant, playing a significant role in increasing the in vivo efficacy. IMPORTANCE The rapid rise of antibiotic resistance in bacterial pathogens is now considered a major global health crisis. New strategies are needed to block the development of resistance and to extend the life of antibiotics. The SOS response is a promising target for developing therapeutics to reduce the acquisition of antibiotic resistance and enhance the bactericidal activity of antimicrobial agents such as quinolones. Significant questions remain regarding its impact as a strategy for the reversion or resensitization of antibiotic-resistant bacteria. To address this

The SbSOS1 gene from the extreme halophyte Salicornia brachiata enhances Na+ loading in xylem and confers salt tolerance in transgenic tobacco

Directory of Open Access Journals (Sweden)

Yadav Narendra

2012-10-01

Full Text Available Abstract Background Soil salinity adversely affects plant growth and development and disturbs intracellular ion homeostasis resulting cellular toxicity. The Salt Overly Sensitive 1 (SOS1 gene encodes a plasma membrane Na+/H+ antiporter that plays an important role in imparting salt stress tolerance to plants. Here, we report the cloning and characterisation of the SbSOS1 gene from Salicornia brachiata, an extreme halophyte. Results The SbSOS1 gene is 3774 bp long and encodes a protein of 1159 amino acids. SbSOS1 exhibited a greater level of constitutive expression in roots than in shoots and was further increased by salt stress. Overexpressing the S. brachiata SbSOS1 gene in tobacco conferred high salt tolerance, promoted seed germination and increased root length, shoot length, leaf area, fresh weight, dry weight, relative water content (RWC, chlorophyll, K+/Na+ ratio, membrane stability index, soluble sugar, proline and amino acid content relative to wild type (WT plants. Transgenic plants exhibited reductions in electrolyte leakage, reactive oxygen species (ROS and MDA content in response to salt stress, which probably occurred because of reduced cytosolic Na+ content and oxidative damage. At higher salt stress, transgenic tobacco plants exhibited reduced Na+ content in root and leaf and higher concentrations in stem and xylem sap relative to WT, which suggests a role of SbSOS1 in Na+ loading to xylem from root and leaf tissues. Transgenic lines also showed increased K+ and Ca2+ content in root tissue compared to WT, which reflect that SbSOS1 indirectly affects the other transporters activity. Conclusions Overexpression of SbSOS1 in tobacco conferred a high degree of salt tolerance, enhanced plant growth and altered physiological and biochemical parameters in response to salt stress. In addition to Na+ efflux outside the plasma membrane, SbSOS1 also helps to maintain variable Na+ content in different organs and also affect the other

The SbSOS1 gene from the extreme halophyte Salicornia brachiata enhances Na+ loading in xylem and confers salt tolerance in transgenic tobacco

Science.gov (United States)

2012-01-01

Background Soil salinity adversely affects plant growth and development and disturbs intracellular ion homeostasis resulting cellular toxicity. The Salt Overly Sensitive 1 (SOS1) gene encodes a plasma membrane Na+/H+ antiporter that plays an important role in imparting salt stress tolerance to plants. Here, we report the cloning and characterisation of the SbSOS1 gene from Salicornia brachiata, an extreme halophyte. Results The SbSOS1 gene is 3774 bp long and encodes a protein of 1159 amino acids. SbSOS1 exhibited a greater level of constitutive expression in roots than in shoots and was further increased by salt stress. Overexpressing the S. brachiata SbSOS1 gene in tobacco conferred high salt tolerance, promoted seed germination and increased root length, shoot length, leaf area, fresh weight, dry weight, relative water content (RWC), chlorophyll, K+/Na+ ratio, membrane stability index, soluble sugar, proline and amino acid content relative to wild type (WT) plants. Transgenic plants exhibited reductions in electrolyte leakage, reactive oxygen species (ROS) and MDA content in response to salt stress, which probably occurred because of reduced cytosolic Na+ content and oxidative damage. At higher salt stress, transgenic tobacco plants exhibited reduced Na+ content in root and leaf and higher concentrations in stem and xylem sap relative to WT, which suggests a role of SbSOS1 in Na+ loading to xylem from root and leaf tissues. Transgenic lines also showed increased K+ and Ca2+ content in root tissue compared to WT, which reflect that SbSOS1 indirectly affects the other transporters activity. Conclusions Overexpression of SbSOS1 in tobacco conferred a high degree of salt tolerance, enhanced plant growth and altered physiological and biochemical parameters in response to salt stress. In addition to Na+ efflux outside the plasma membrane, SbSOS1 also helps to maintain variable Na+ content in different organs and also affect the other transporters activity indirectly

A plasmid-encoded UmuD homologue regulates expression of Pseudomonas aeruginosa SOS genes.

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Díaz-Magaña, Amada; Alva-Murillo, Nayeli; Chávez-Moctezuma, Martha P; López-Meza, Joel E; Ramírez-Díaz, Martha I; Cervantes, Carlos

2015-07-01

The Pseudomonas aeruginosa plasmid pUM505 contains the umuDC operon that encodes proteins similar to error-prone repair DNA polymerase V. The umuC gene appears to be truncated and its product is probably not functional. The umuD gene, renamed umuDpR, possesses an SOS box overlapped with a Sigma factor 70 type promoter; accordingly, transcriptional fusions revealed that the umuDpR gene promoter is activated by mitomycin C. The predicted sequence of the UmuDpR protein displays 23 % identity with the Ps. aeruginosa SOS-response LexA repressor. The umuDpR gene caused increased MMC sensitivity when transferred to the Ps. aeruginosa PAO1 strain. As expected, PAO1-derived knockout lexA-  mutant PW6037 showed resistance to MMC; however, when the umuDpR gene was transferred to PW6037, MMC resistance level was reduced. These data suggested that UmuDpR represses the expression of SOS genes, as LexA does. To test whether UmuDpR exerts regulatory functions, expression of PAO1 SOS genes was evaluated by reverse transcription quantitative PCR assays in the lexA-  mutant with or without the pUC_umuD recombinant plasmid. Expression of lexA, imuA and recA genes increased 3.4-5.3 times in the lexA-  mutant, relative to transcription of the corresponding genes in the lexA+ strain, but decreased significantly in the lexA- /umuDpR transformant. These results confirmed that the UmuDpR protein is a repressor of Ps. aeruginosa SOS genes controlled by LexA. Electrophoretic mobility shift assays, however, did not show binding of UmuDpR to 5' regions of SOS genes, suggesting an indirect mechanism of regulation.

Motility of Pseudomonas aeruginosa contributes to SOS-inducible biofilm formation.

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Chellappa, Shakinah T; Maredia, Reshma; Phipps, Kara; Haskins, William E; Weitao, Tao

2013-12-01

DNA-damaging antibiotics such as ciprofloxacin induce biofilm formation and the SOS response through autocleavage of SOS-repressor LexA in Pseudomonas aeruginosa. However, the biofilm-SOS connection remains poorly understood. It was investigated with 96-well and lipid biofilm assays. The effects of ciprofloxacin were examined on biofilm stimulation of the SOS mutant and wild-type strains. The stimulation observed in the wild-type in which SOS was induced was reduced in the mutant in which LexA was made non-cleavable (LexAN) and thus SOS non-inducible. Therefore, the stimulation appeared to involve SOS. The possible mechanisms of inducible biofilm formation were explored by subproteomic analysis of outer membrane fractions extracted from biofilms. The data predicted an inhibitory role of LexA in flagellum function. This premise was tested first by functional and morphological analyses of flagellum-based motility. The flagellum swimming motility decreased in the LexAN strain treated with ciprofloxacin. Second, the motility-biofilm assay was performed, which tested cell migration and biofilm formation. The results showed that wild-type biofilm increased significantly over the LexAN. These results suggest that LexA repression of motility, which is the initial event in biofilm development, contributes to repression of SOS-inducible biofilm formation. Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

The Salt Overly Sensitive (SOS) pathway: established and emerging roles.

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Ji, Hongtao; Pardo, José M; Batelli, Giorgia; Van Oosten, Michael J; Bressan, Ray A; Li, Xia

2013-03-01

Soil salinity is a growing problem around the world with special relevance in farmlands. The ability to sense and respond to environmental stimuli is among the most fundamental processes that enable plants to survive. At the cellular level, the Salt Overly Sensitive (SOS) signaling pathway that comprises SOS3, SOS2, and SOS1 has been proposed to mediate cellular signaling under salt stress, to maintain ion homeostasis. Less well known is how cellularly heterogenous organs couple the salt signals to homeostasis maintenance of different types of cells and to appropriate growth of the entire organ and plant. Recent evidence strongly indicates that different regulatory mechanisms are adopted by roots and shoots in response to salt stress. Several reports have stated that, in roots, the SOS proteins may have novel roles in addition to their functions in sodium homeostasis. SOS3 plays a critical role in plastic development of lateral roots through modulation of auxin gradients and maxima in roots under mild salt conditions. The SOS proteins also play a role in the dynamics of cytoskeleton under stress. These results imply a high complexity of the regulatory networks involved in plant response to salinity. This review focuses on the emerging complexity of the SOS signaling and SOS protein functions, and highlights recent understanding on how the SOS proteins contribute to different responses to salt stress besides ion homeostasis.

The Walker A motif mutation recA4159 abolishes the SOS response and recombination in a recA730 mutant of Escherichia coli.

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Šimatović, Ana; Mitrikeski, Petar T; Vlašić, Ignacija; Sopta, Mary; Brčić-Kostić, Krunoslav

2016-01-01

In bacteria, the RecA protein forms recombinogenic filaments required for the SOS response and DNA recombination. In order to form a recombinogenic filament, wild type RecA needs to bind ATP and to interact with mediator proteins. The RecA730 protein is a mutant version of RecA with superior catalytic abilities, allowing filament formation without the help of mediator proteins. The mechanism of RecA730 filament formation is not well understood, and the question remains as to whether the RecA730 protein requires ATP binding in order to become competent for filament formation. We examined two mutants, recA730,4159 (presumed to be defective for ATP binding) and recA730,2201 (defective for ATP hydrolysis), and show that they have different properties with respect to SOS induction, conjugational recombination and double-strand break repair. We show that ATP binding is essential for all RecA730 functions, while ATP hydrolysis is required only for double-strand break repair. Our results emphasize the similarity of the SOS response and conjugational recombination, neither of which requires ATP hydrolysis by RecA730. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Mutational specificity of SOS mutagenesis

International Nuclear Information System (INIS)

Kato, Takeshi

1986-01-01

In an approach to the isolation of mutants of E. coli unable to produce mutations by ultraviolet light, the author has found new umuC-mutants. Their properties could be explained by ''SOS hypothesis of Radman and Witkin'', which has now been justified by many investigators. Analysis of the umuC region of E. coli chromosome cloned in pSK 100 has led to the conclusion that two genes, umuD and umuC, having the capacity of mutation induction express in the same mechanism as that of SOS genes, which is known to be inhibited by LexA protein bonding to ''SOS box'' found at promotor region. Suppressor analysis for mutational specificity has revealed: (i) umuDC-independent mutagens, such as EMS and (oh) 4 Cy, induce selected base substitution alone; and (ii) umuDC-dependent mutagens, such as X-rays and gamma-rays, induce various types of base substitution simultaneously, although they have mutational specificity. In the umuDC-dependent processes of basechange mutagenesis, the spectra of base substitution were a mixture of base substitution reflecting the specific base damages induced by individual mutagens and nonspecific base substitution. In conclusion, base substitution plays the most important role in umuDC-dependent mutagenesis, although mutagenesis of umuDC proteins remains uncertain. (Namekawa, K.)

Absence of both Sos-1 and Sos-2 in peripheral CD4+ T cells leads to PI3K pathway activation and defects in migration

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Guittard, Geoffrey; Kortum, Robert L; Balagopalan, Lakshmi; Çuburu, Nicolas; Nguyen, Phan; Sommers, Connie L; Samelson, Lawrence E

2015-01-01

Sos-1 and Sos-2 are ubiquitously expressed Ras-Guanine Exchange Factors involved in Erk-MAP kinase pathway activation. Using mice lacking genes encoding Sos-1 and Sos-2, we evaluated the role of these proteins in peripheral T-cell signaling and function. Our results confirmed that TCR-mediated Erk activation in peripheral CD4+ T cells does not depend on Sos-1 and Sos-2, although IL-2-mediated Erk activation does. Unexpectedly, however, we show an increase in AKT phosphorylation in Sos-1/2dKO CD4+ T cells upon TCR and IL-2 stimulation. Activation of AKT was likely a consequence of increased recruitment of PI3K to Grb2 upon TCR and/or IL-2 stimulation in Sos-1/2dKO CD4+ T cells. The increased activity of the PI3K/AKT pathway led to downregulation of the surface receptor CD62L in Sos-1/2dKO T cells and a subsequent impairment in T-cell migration. PMID:25973715

Switching of the positive feedback for RAS activation by a concerted function of SOS membrane association domains.

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Nakamura, Yuki; Hibino, Kayo; Yanagida, Toshio; Sako, Yasushi

2016-01-01

Son of sevenless (SOS) is a guanine nucleotide exchange factor that regulates cell behavior by activating the small GTPase RAS. Recent in vitro studies have suggested that an interaction between SOS and the GTP-bound active form of RAS generates a positive feedback loop that propagates RAS activation. However, it remains unclear how the multiple domains of SOS contribute to the regulation of the feedback loop in living cells. Here, we observed single molecules of SOS in living cells to analyze the kinetics and dynamics of SOS behavior. The results indicate that the histone fold and Grb2-binding domains of SOS concertedly produce an intermediate state of SOS on the cell surface. The fraction of the intermediated state was reduced in positive feedback mutants, suggesting that the feedback loop functions during the intermediate state. Translocation of RAF, recognizing the active form of RAS, to the cell surface was almost abolished in the positive feedback mutants. Thus, the concerted functions of multiple membrane-associating domains of SOS governed the positive feedback loop, which is crucial for cell fate decision regulated by RAS.

Absence of both Sos-1 and Sos-2 in peripheral CD4(+) T cells leads to PI3K pathway activation and defects in migration.

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Guittard, Geoffrey; Kortum, Robert L; Balagopalan, Lakshmi; Çuburu, Nicolas; Nguyen, Phan; Sommers, Connie L; Samelson, Lawrence E

2015-08-01

Sos-1 and Sos-2 are ubiquitously expressed Ras-guanine exchange factors involved in Erk-MAP kinase pathway activation. Using mice lacking genes encoding Sos-1 and Sos-2, we evaluated the role of these proteins in peripheral T-cell signaling and function. Our results confirmed that TCR-mediated Erk activation in peripheral CD4(+) T cells does not depend on Sos-1 and Sos-2, although IL-2-mediated Erk activation does. Unexpectedly, however, we show an increase in AKT phosphorylation in Sos-1/2dKO CD4(+) T cells upon TCR and IL-2 stimulation. Activation of AKT was likely a consequence of increased recruitment of PI3K to Grb2 upon TCR and/or IL-2 stimulation in Sos-1/2dKO CD4(+) T cells. The increased activity of the PI3K/AKT pathway led to downregulation of the surface receptor CD62L in Sos-1/2dKO T cells and a subsequent impairment in T-cell migration. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Inhibitors of Ras-SOS Interactions.

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Lu, Shaoyong; Jang, Hyunbum; Zhang, Jian; Nussinov, Ruth

2016-04-19

Activating Ras mutations are found in about 30 % of human cancers. Ras activation is regulated by guanine nucleotide exchange factors, such as the son of sevenless (SOS), which form protein-protein interactions (PPIs) with Ras and catalyze the exchange of GDP by GTP. This is the rate-limiting step in Ras activation. However, Ras surfaces lack any evident suitable pockets where a molecule might bind tightly, rendering Ras proteins still 'undruggable' for over 30 years. Among the alternative approaches is the design of inhibitors that target the Ras-SOS PPI interface, a strategy that is gaining increasing recognition for treating Ras mutant cancers. Herein we focus on data that has accumulated over the past few years pertaining to the design of small-molecule modulators or peptide mimetics aimed at the interface of the Ras-SOS PPI. We emphasize, however, that even if such Ras-SOS therapeutics are potent, drug resistance may emerge. To counteract this development, we propose "pathway drug cocktails", that is, drug combinations aimed at parallel (or compensatory) pathways. A repertoire of classified cancer, cell/tissue, and pathway/protein combinations would be beneficial toward this goal. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mutation-Specific Mechanisms of Hyperactivation of Noonan Syndrome SOS Molecules Detected with Single-molecule Imaging in Living Cells.

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Nakamura, Yuki; Umeki, Nobuhisa; Abe, Mitsuhiro; Sako, Yasushi

2017-10-26

Noonan syndrome (NS) is a congenital hereditary disorder associated with developmental and cardiac defects. Some patients with NS carry mutations in SOS, a guanine nucleotide exchange factor (GEF) for the small GTPase RAS. NS mutations have been identified not only in the GEF domain, but also in various domains of SOS, suggesting that multiple mechanisms disrupt SOS function. In this study, we examined three NS mutations in different domains of SOS to clarify the abnormality in its translocation to the plasma membrane, where SOS activates RAS. The association and dissociation kinetics between SOS tagged with a fluorescent protein and the living cell surface were observed in single molecules. All three mutants showed increased affinity for the plasma membrane, inducing excessive RAS signalling. However, the mechanisms by which their affinity was increased were specific to each mutant. Conformational disorder in the resting state, increased probability of a conformational change on the plasma membrane, and an increased association rate constant with the membrane receptor are the suggested mechanisms. These different properties cause the specific phenotypes of the mutants, which should be rescuable with different therapeutic strategies. Therefore, single-molecule kinetic analyses of living cells are useful for the pathological analysis of genetic diseases.

The recX gene product is involved in the SOS response in Herbaspirillum seropedicae

International Nuclear Information System (INIS)

Galvao, C.W.; Pedrosa, F.O.; Souza, E.M.; Yates, M.G.; Chubatsu, L.S.; Steffens, M.B.R.

2003-01-01

The recA and the recX genes of Herbaspirillum seropedicae were sequenced. The recX is located 359 bp downstream from recA. Sequence analysis indicated the presence of a putative operator site overlapping a probable σ 70 -dependent promoter upstream of recA and a transcription terminator downstream from recX, with no apparent promoter sequence in the intergenic region. Transcriptional analysis using lacZ promoter fusions indicated that recA expression increased three- to fourfold in the presence of methyl methanesulfonate (MMS). The roles of recA and recX genes in the SOS response were determined from studies of chromosomal mutants. The recA mutant showed the highest sensitivity to MMS and UV, and the recX mutant had an intermediate sensitivity, compared with the wild type (SMR1), confirming the essential role of the RecA protein in cell viability in the presence of mutagenic agents and also indicating a role for RecX in the SOS response. (author)

The recX gene product is involved in the SOS response in Herbaspirillum seropedicae

Energy Technology Data Exchange (ETDEWEB)

Galvao, C.W.; Pedrosa, F.O.; Souza, E.M.; Yates, M.G.; Chubatsu, L.S.; Steffens, M.B.R. [Univ. Federal do Parana, Dept. of Biochemistry and Molecular Biology, Curitiba (Brazil)]. E-mail: steffens@bioufpr.br

2003-02-15

The recA and the recX genes of Herbaspirillum seropedicae were sequenced. The recX is located 359 bp downstream from recA. Sequence analysis indicated the presence of a putative operator site overlapping a probable {sigma}{sup 70}-dependent promoter upstream of recA and a transcription terminator downstream from recX, with no apparent promoter sequence in the intergenic region. Transcriptional analysis using lacZ promoter fusions indicated that recA expression increased three- to fourfold in the presence of methyl methanesulfonate (MMS). The roles of recA and recX genes in the SOS response were determined from studies of chromosomal mutants. The recA mutant showed the highest sensitivity to MMS and UV, and the recX mutant had an intermediate sensitivity, compared with the wild type (SMR1), confirming the essential role of the RecA protein in cell viability in the presence of mutagenic agents and also indicating a role for RecX in the SOS response. (author)

The recX gene product is involved in the SOS response in Herbaspirillum seropedicae.

Science.gov (United States)

Galvão, Carolina W; Pedrosa, Fábio O; Souza, Emanuel M; Yates, M Geoffrey; Chubatsu, Leda S; Steffens, Maria Berenice R

2003-02-01

The recA and the recX genes of Herbaspirillum seropedicae were sequenced. The recX is located 359 bp downstream from recA. Sequence analysis indicated the presence of a putative operator site overlapping a probable sigma70-dependent promoter upstream of recA and a transcription terminator downstream from recX, with no apparent promoter sequence in the intergenic region. Transcriptional analysis using lacZ promoter fusions indicated that recA expression increased three- to fourfold in the presence of methyl methanesulfonate (MMS). The roles of recA and recX genes in the SOS response were determined from studies of chromosomal mutants. The recA mutant showed the highest sensitivity to MMS and UV, and the recX mutant had an intermediate sensitivity, compared with the wild type (SMR1), confirming the essential role of the RecA protein in cell viability in the presence of mutagenic agents and also indicating a role for RecX in the SOS response.

Identification of genes involved in low aminoglycoside-induced SOS response in Vibrio cholerae: a role for transcription stalling and Mfd helicase.

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Baharoglu, Zeynep; Babosan, Anamaria; Mazel, Didier

2014-02-01

Sub-inhibitory concentrations (sub-MIC) of antibiotics play a very important role in selection and development of resistances. Unlike Escherichia coli, Vibrio cholerae induces its SOS response in presence of sub-MIC aminoglycosides. A role for oxidized guanine residues was observed, but the mechanisms of this induction remained unclear. To select for V. cholerae mutants that do not induce low aminoglycoside-mediated SOS induction, we developed a genetic screen that renders induction of SOS lethal. We identified genes involved in this pathway using two strategies, inactivation by transposition and gene overexpression. Interestingly, we obtained mutants inactivated for the expression of proteins known to destabilize the RNA polymerase complex. Reconstruction of the corresponding mutants confirmed their specific involvement in induction of SOS by low aminoglycoside concentrations. We propose that DNA lesions formed on aminoglycoside treatment are repaired through the formation of single-stranded DNA intermediates, inducing SOS. Inactivation of functions that dislodge RNA polymerase leads to prolonged stalling on these lesions, which hampers SOS induction and repair and reduces viability under antibiotic stress. The importance of these mechanisms is illustrated by a reduction of aminoglycoside sub-MIC. Our results point to a central role for transcription blocking at DNA lesions in SOS induction, so far underestimated.

Mathematical model of the SOS response regulation in wild-type Escherichia coli

International Nuclear Information System (INIS)

Aksenov, S.V.

1997-01-01

Regulation of the SOS response in Escherichia coli, which is a set of inducible cellular reactions introduced after DNA damage, is due to specific interaction of LexA and RecA proteins. LexA protein is a common repressor of the genes of the SOS system, and RecA protein, once transiently activated by the so-called SOS-inducing signal, promotes LexA protein destruction. We have described the SOS regulation by means of differential equations with regard to LexA and RecA concentrations elsewhere. The 'input' function for model equations is the level of the SOS-inducing signal against time. Here we present a means for calculating the concentration of single-stranded DNA (SOS-inducing signal) as a function of time in wild-type cells after ultraviolet irradiation. With model equations one can simulate kinetic curves of SOS regulatory proteins after DNA damage to survey the SOS response kinetics. Simulation of LexA protein kinetics agrees with experimental data. We compare simulated LexA kinetic curves in wild-type and uνr - mutant bacteria, which is useful in investigating the way uνrABC-dependent excision repair modulates the SOS response kinetics. Possible applications of the model to investigating various aspects of the SOS induction are discussed

Influence of very short patch mismatch repair on SOS inducing lesions after aminoglycoside treatment in Escherichia coli.

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Baharoglu, Zeynep; Mazel, Didier

2014-01-01

Low concentrations of aminoglycosides induce the SOS response in Vibrio cholerae but not in Escherichia coli. In order to determine whether a specific factor present in E. coli prevents this induction, we developed a genetic screen where only SOS inducing mutants are viable. We identified the vsr gene coding for the Vsr protein of the very short patch mismatch repair (VSPR) pathway. The effect of mismatch repair (MMR) mutants was also studied. We propose that lesions formed upon aminoglycoside treatment are preferentially repaired by VSPR without SOS induction in E. coli and by MMR when VSPR is impaired. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Interaction of caffeine with the SOS response pathway in Escherichia coli.

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Whitney, Alyssa K; Weir, Tiffany L

2015-01-01

Previous studies have highlighted the antimicrobial activity of caffeine, both individually and in combination with other compounds. A proposed mechanism for caffeine's antimicrobial effects is inhibition of bacterial DNA repair pathways. The current study examines the influence of sub-lethal caffeine levels on the growth and morphology of SOS response pathway mutants of Escherichia coli. Growth inhibition after treatment with caffeine and methyl methane sulfonate (MMS), a mutagenic agent, was determined for E. coli mutants lacking key genes in the SOS response pathway. The persistence of caffeine's effects was explored by examining growth and morphology of caffeine and MMS-treated bacterial isolates in the absence of selective pressure. Caffeine significantly reduced growth of E. coli recA- and uvrA-mutants treated with MMS. However, there was no significant difference in growth between umuC-isolates treated with MMS alone and MMS in combination with caffeine after 48 h of incubation. When recA-isolates from each treatment group were grown in untreated medium, bacterial isolates that had been exposed to MMS or MMS with caffeine showed increased growth relative to controls and caffeine-treated isolates. Morphologically, recA-isolates that had been treated with caffeine and both caffeine and MMS together had begun to display filamentous growth. Caffeine treatment further reduced growth of recA- and uvrA-mutants treated with MMS, despite a non-functional SOS response pathway. However, addition of caffeine had very little effect on MMS inhibition of umuC-mutants. Thus, growth inhibition of E. coli with caffeine treatment may be driven by caffeine interaction with UmuC, but also appears to induce damage by additional mechanisms as evidenced by the additive effects of caffeine in recA- and uvrA-mutants.

A cellulose synthase-like protein is required for osmotic stress tolerance in Arabidopsis

KAUST Repository

Zhu, Jianhua

2010-04-16

Osmotic stress imposed by soil salinity and drought stress significantly affects plant growth and development, but osmotic stress sensing and tolerance mechanisms are not well understood. Forward genetic screens using a root-bending assay have previously identified salt overly sensitive (sos) mutants of Arabidopsis that fall into five loci, SOS1 to SOS5. These loci are required for the regulation of ion homeostasis or cell expansion under salt stress, but do not play a major role in plant tolerance to the osmotic stress component of soil salinity or drought. Here we report an additional sos mutant, sos6-1, which defines a locus essential for osmotic stress tolerance. sos6-1 plants are hypersensitive to salt stress and osmotic stress imposed by mannitol or polyethylene glycol in culture media or by water deficit in the soil. SOS6 encodes a cellulose synthase-like protein, AtCSLD5. Only modest differences in cell wall chemical composition could be detected, but we found that sos6-1 mutant plants accumulate high levels of reactive oxygen species (ROS) under osmotic stress and are hypersensitive to the oxidative stress reagent methyl viologen. The results suggest that SOS6/AtCSLD5 is not required for normal plant growth and development but has a critical role in osmotic stress tolerance and this function likely involves its regulation of ROS under stress. © 2010 Blackwell Publishing Ltd.

Adherence to abiotic surface induces SOS response in Escherichia coli K-12 strains under aerobic and anaerobic conditions.

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Costa, Suelen B; Campos, Ana Carolina C; Pereira, Ana Claudia M; de Mattos-Guaraldi, Ana Luiza; Júnior, Raphael Hirata; Rosa, Ana Cláudia P; Asad, Lídia M B O

2014-09-01

During the colonization of surfaces, Escherichia coli bacteria often encounter DNA-damaging agents and these agents can induce several defence mechanisms. Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species (ROS) generated by chemical and physical agents or by metabolism. In this work, we have evaluated whether the interaction with an abiotic surface by mutants derived from E. coli K-12 deficient in some enzymes that are part of BER causes DNA damage and associated filamentation. Moreover, we studied the role of endonuclease V (nfi gene; 1506 mutant strain) in biofilm formation. Endonuclease V is an enzyme that is involved in DNA repair of nitrosative lesions. We verified that endonuclease V is involved in biofilm formation. Our results showed more filamentation in the xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) than in the wild-type strain (AB1157). By contrast, the mutant nfi did not present filamentation in biofilm, although its wild-type strain (1466) showed rare filaments in biofilm. The filamentation of bacterial cells attaching to a surface was a consequence of SOS induction measured by the SOS chromotest. However, biofilm formation depended on the ability of the bacteria to induce the SOS response since the mutant lexA Ind(-) did not induce the SOS response and did not form any biofilm. Oxygen tension was an important factor for the interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, our results showed that the presence or absence of oxygen did not affect the viability of BW9091 and BW535 strains. The nfi mutant and its wild-type did not exhibit decreased biofilm formation under anaerobic conditions. Scanning electron microscopy was also performed on the E. coli K-12 strains that had adhered to the glass, and we observed the presence of a structure similar to an extracellular matrix that depended on the

Gain-of-function SOS1 mutations cause a distinctive form of noonansyndrome

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Tartaglia, Marco; Pennacchio, Len A.; Zhao, Chen; Yadav, KamleshK.; Fodale, Valentina; Sarkozy, Anna; Pandit, Bhaswati; Oishi, Kimihiko; Martinelli, Simone; Schackwitz, Wendy; Ustaszewska, Anna; Martin, Joes; Bristow, James; Carta, Claudio; Lepri, Francesca; Neri, Cinzia; Vasta,Isabella; Gibson, Kate; Curry, Cynthia J.; Lopez Siguero, Juan Pedro; Digilio, Maria Cristina; Zampino, Giuseppe; Dallapiccola, Bruno; Bar-Sagi, Dafna; Gelb, Brude D.

2006-09-01

Noonan syndrome (NS) is a developmental disordercharacterized by short stature, facial dysmorphia, congenital heartdefects and skeletal anomalies1. Increased RAS-mitogenactivated proteinkinase (MAPK) signaling due to PTPN11 and KRAS mutations cause 50 percentof NS2-6. Here, we report that 22 of 129 NS patients without PTPN11 orKRAS mutation (17 percent) have missense mutations in SOS1, which encodesa RAS-specific guanine nucleotide exchange factor (GEF). SOS1 mutationscluster at residues implicated in the maintenance of SOS1 in itsautoinhibited form and ectopic expression of two NS-associated mutantsinduced enhanced RAS activation. The phenotype associated with SOS1defects is distinctive, although within NS spectrum, with a highprevalence of ectodermal abnormalities but generally normal developmentand linear growth. Our findings implicate for the first timegain-of-function mutations in a RAS GEF in inherited disease and define anew mechanism by which upregulation of the RAS pathway can profoundlychange human development.

Rare variants in SOS2 and LZTR1 are associated with Noonan syndrome.

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Yamamoto, Guilherme Lopes; Aguena, Meire; Gos, Monika; Hung, Christina; Pilch, Jacek; Fahiminiya, Somayyeh; Abramowicz, Anna; Cristian, Ingrid; Buscarilli, Michelle; Naslavsky, Michel Satya; Malaquias, Alexsandra C; Zatz, Mayana; Bodamer, Olaf; Majewski, Jacek; Jorge, Alexander A L; Pereira, Alexandre C; Kim, Chong Ae; Passos-Bueno, Maria Rita; Bertola, Débora Romeo

2015-06-01

Noonan syndrome is an autosomal dominant, multisystemic disorder caused by dysregulation of the RAS/mitogen activated protein kinase (MAPK) pathway. Heterozygous, pathogenic variants in 11 known genes account for approximately 80% of cases. The identification of novel genes associated with Noonan syndrome has become increasingly challenging, since they might be responsible for very small fractions of the cases. A cohort of 50 Brazilian probands negative for pathogenic variants in the known genes associated with Noonan syndrome was tested through whole-exome sequencing along with the relatives in the familial cases. Families from the USA and Poland with mutations in the newly identified genes were included subsequently. We identified rare, segregating or de novo missense variants in SOS2 and LZTR1 in 4% and 8%, respectively, of the 50 Brazilian probands. SOS2 and LZTR1 variants were also found to segregate in one American and one Polish family. Notably, SOS2 variants were identified in patients with marked ectodermal involvement, similar to patients with SOS1 mutations. We identified two novel genes, SOS2 and LZTR1, associated with Noonan syndrome, thereby expanding the molecular spectrum of RASopathies. Mutations in these genes are responsible for approximately 3% of all patients with Noonan syndrome. While SOS2 is a natural candidate, because of its homology with SOS1, the functional role of LZTR1 in the RAS/MAPK pathway is not known, and it could not have been identified without the large pedigrees. Additional functional studies are needed to elucidate the role of LZTR1 in RAS/MAPK signalling and in the pathogenesis of Noonan syndrome. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Tolerance of Escherichia coli to fluoroquinolone antibiotics depends on specific components of the SOS response pathway.

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Theodore, Alyssa; Lewis, Kim; Vulic, Marin

2013-12-01

Bacteria exposed to bactericidal fluoroquinolone (FQ) antibiotics can survive without becoming genetically resistant. Survival of these phenotypically resistant cells, commonly called "persisters," depends on the SOS gene network. We have examined mutants in all known SOS-regulated genes to identify functions essential for tolerance in Escherichia coli. The absence of DinG and UvrD helicases and the Holliday junction processing enzymes RuvA and RuvB leads to a decrease in survival. Analysis of the respective mutants indicates that, in addition to repair of double-strand breaks, tolerance depends on the repair of collapsed replication forks and stalled transcription complexes. Mutation in recF results in increased survival, which identifies RecAF recombination as a poisoning mechanism not previously linked to FQ lethality. DinG acts upstream of SOS promoting its induction, whereas RuvAB participates in repair only. UvrD directly promotes all repair processes initiated by FQ-induced damage and prevents RecAF-dependent misrepair, making it one of the crucial SOS functions required for tolerance.

Ribonuclease E modulation of the bacterial SOS response.

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Robert Manasherob

Full Text Available Plants, animals, bacteria, and Archaea all have evolved mechanisms to cope with environmental or cellular stress. Bacterial cells respond to the stress of DNA damage by activation of the SOS response, the canonical RecA/LexA-dependent signal transduction pathway that transcriptionally derepresses a multiplicity of genes-leading to transient arrest of cell division and initiation of DNA repair. Here we report the previously unsuspected role of E. coli endoribonuclease RNase E in regulation of the SOS response. We show that RNase E deletion or inactivation of temperature-sensitive RNase E protein precludes normal initiation of SOS. The ability of RNase E to regulate SOS is dynamic, as down regulation of RNase E following DNA damage by mitomycin C resulted in SOS termination and restoration of RNase E function leads to resumption of a previously aborted response. Overexpression of the RraA protein, which binds to the C-terminal region of RNase E and modulates the actions of degradosomes, recapitulated the effects of RNase E deficiency. Possible mechanisms for RNase E effects on SOS are discussed.

Ribonuclease E modulation of the bacterial SOS response.

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Manasherob, Robert; Miller, Christine; Kim, Kwang-sun; Cohen, Stanley N

2012-01-01

Plants, animals, bacteria, and Archaea all have evolved mechanisms to cope with environmental or cellular stress. Bacterial cells respond to the stress of DNA damage by activation of the SOS response, the canonical RecA/LexA-dependent signal transduction pathway that transcriptionally derepresses a multiplicity of genes-leading to transient arrest of cell division and initiation of DNA repair. Here we report the previously unsuspected role of E. coli endoribonuclease RNase E in regulation of the SOS response. We show that RNase E deletion or inactivation of temperature-sensitive RNase E protein precludes normal initiation of SOS. The ability of RNase E to regulate SOS is dynamic, as down regulation of RNase E following DNA damage by mitomycin C resulted in SOS termination and restoration of RNase E function leads to resumption of a previously aborted response. Overexpression of the RraA protein, which binds to the C-terminal region of RNase E and modulates the actions of degradosomes, recapitulated the effects of RNase E deficiency. Possible mechanisms for RNase E effects on SOS are discussed.

[Expressions of Ras and Sos1 in epithelial ovarian cancer tissues and their clinical significance].

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Xiao, Zheng-Hua; Linghu, Hua; Liu, Qian-Fen

2016-11-20

To detect the expressions of Ras and Sos1 proteins in human epithelial ovarian cancer (EOC) tissues and explore their correlation with the clinicopathological features of the patients. The expressions of Ras and Sos1 proteins were detected immunohistochemically in 62 EOC tissues, 5 borderline ovarian cancer tissues, 15 benign epithelial ovarian neoplasm tissues, and 18 normal ovarian tissues. The EOC tissues showed significantly higher expression levels of both Ras and Sos1 than the other tissues tested (Ptissues, Ras and Sos1 proteins were expressed mostly on the cell membrane and in the cytoplasm. The expression level of Ras was correlated with pathological types of the tumor (Ptissue-specific variation of Ras expression can lend support to a specific diagnosis of ovarian serous adenocarcinoma. The association of Ras and Sos1 protein expression with the tumor-free survival time of the patients awaits further investigation with a larger sample size.

Thymineless death is inhibited by CsrA in Escherichia coli lacking the SOS response.

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Hamilton, Holly M; Wilson, Ray; Blythe, Martin; Nehring, Ralf B; Fonville, Natalie C; Louis, Edward J; Rosenberg, Susan M

2013-11-01

Thymineless death (TLD) is the rapid loss of colony-forming ability in bacterial, yeast and human cells starved for thymine, and is the mechanism of action of common chemotherapeutic drugs. In Escherichia coli, significant loss of viability during TLD requires the SOS replication-stress/DNA-damage response, specifically its role in inducing the inhibitor of cell division, SulA. An independent RecQ- and RecJ-dependent TLD pathway accounts for a similarly large additional component of TLD, and a third SOS- and RecQ/J-independent TLD pathway has also been observed. Although two groups have implicated the SOS-response in TLD, an SOS-deficient mutant strain from an earlier study was found to be sensitive to thymine deprivation. We performed whole-genome resequencing on that SOS-deficient strain and find that, compared with the SOS-proficient control strain, it contains five mutations in addition to the SOS-blocking lexA(Ind(-)) mutation. One of the additional mutations, csrA, confers TLD sensitivity specifically in SOS-defective strains. We find that CsrA, a carbon storage regulator, reduces TLD in SOS- or SulA-defective cells, and that the increased TLD that occurs in csrA(-) SOS-defective cells is dependent on RecQ. We consider a hypothesis in which the modulation of nucleotide pools by CsrA might inhibit TLD specifically in SOS-deficient (SulA-deficient) cells. Copyright © 2013 Elsevier B.V. All rights reserved.

Suppression of the E. coli SOS response by dNTP pool changes.

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Maslowska, Katarzyna H; Makiela-Dzbenska, Karolina; Fijalkowska, Iwona J; Schaaper, Roel M

2015-04-30

The Escherichia coli SOS system is a well-established model for the cellular response to DNA damage. Control of SOS depends largely on the RecA protein. When RecA is activated by single-stranded DNA in the presence of a nucleotide triphosphate cofactor, it mediates cleavage of the LexA repressor, leading to expression of the 30(+)-member SOS regulon. RecA activation generally requires the introduction of DNA damage. However, certain recA mutants, like recA730, bypass this requirement and display constitutive SOS expression as well as a spontaneous (SOS) mutator effect. Presently, we investigated the possible interaction between SOS and the cellular deoxynucleoside triphosphate (dNTP) pools. We found that dNTP pool changes caused by deficiencies in the ndk or dcd genes, encoding nucleoside diphosphate kinase and dCTP deaminase, respectively, had a strongly suppressive effect on constitutive SOS expression in recA730 strains. The suppression of the recA730 mutator effect was alleviated in a lexA-deficient background. Overall, the findings suggest a model in which the dNTP alterations in the ndk and dcd strains interfere with the activation of RecA, thereby preventing LexA cleavage and SOS induction. Published by Oxford University Press on behalf of Nucleic Acids Research 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

DinB Upregulation Is the Sole Role of the SOS Response in Stress-Induced Mutagenesis in Escherichia coli

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Galhardo, Rodrigo S.; Do, Robert; Yamada, Masami; Friedberg, Errol C.; Hastings, P. J.; Nohmi, Takehiko; Rosenberg, Susan M.

2009-01-01

Stress-induced mutagenesis is a collection of mechanisms observed in bacterial, yeast, and human cells in which adverse conditions provoke mutagenesis, often under the control of stress responses. Control of mutagenesis by stress responses may accelerate evolution specifically when cells are maladapted to their environments, i.e., are stressed. It is therefore important to understand how stress responses increase mutagenesis. In the Escherichia coli Lac assay, stress-induced point mutagenesis requires induction of at least two stress responses: the RpoS-controlled general/starvation stress response and the SOS DNA-damage response, both of which upregulate DinB error-prone DNA polymerase, among other genes required for Lac mutagenesis. We show that upregulation of DinB is the only aspect of the SOS response needed for stress-induced mutagenesis. We constructed two dinB(oc) (operator-constitutive) mutants. Both produce SOS-induced levels of DinB constitutively. We find that both dinB(oc) alleles fully suppress the phenotype of constitutively SOS-“off” lexA(Ind−) mutant cells, restoring normal levels of stress-induced mutagenesis. Thus, dinB is the only SOS gene required at induced levels for stress-induced point mutagenesis. Furthermore, although spontaneous SOS induction has been observed to occur in only a small fraction of cells, upregulation of dinB by the dinB(oc) alleles in all cells does not promote a further increase in mutagenesis, implying that SOS induction of DinB, although necessary, is insufficient to differentiate cells into a hypermutable condition. PMID:19270270

Phenomenology of an inducible mutagenic DNA repair pathway in Escherichia coli: SOS repair hypothesis

International Nuclear Information System (INIS)

Radman, M.

1974-01-01

A hypothesis is proposed according to which E. coli possesses an inducible DNA repair system. This hypothetical repair, which we call SOS repair, is manifested only following damage to DNA, and requires de novo protein synthesis. SOS repair in E. coli requires some known genetic elements: recA + , lex + and probably zab + . Mutagenesis by ultraviolet light is observed only under conditions of functional SOS repair: we therefore suspect that this is a mutation-prone repair. A number of phenomena and experiments is reviewed which at this point can best be interpreted in terms of an inducible mutagenic DNA repair system. Two recently discovered phenomena support the proposed hypothesis: existence of a mutant (tif) which, after a shift to elevated temperature, mimicks the effect of uv irradiation in regard to repair of phage lambda and uv mutagenesis, apparent activation of SOS repair by introduction into the recipient cell of damaged plasmid or Hfr DNA. Several specific predictions based on SOS repair hypothesis are presented in order to stimulate further experimental tests. (U.S.)

The investigation of SOS-response of Escherichia coli after γ-irradiation by means of SOS-chromotest

International Nuclear Information System (INIS)

Kozubek, S.; Ogievetskaya, M.M.; Krasavin, E.A.; Drasil, V.; Soska, J.

1988-01-01

The kinetics of the E.coli PQ37 SOS-system induction by γ-radiation has been studied by the SOS-chromotest technique. The experimental data are consistent with the following hypotheses. The production of DNA damages inducing the SOS-system is 0,021 Gy -1 per genome. The SOS-system is switched off approximately 200 min after γ-irradiation. The spontaneous triggering of the SOS-system is induced in the exponentially growing cells. The probability of its induction is independent of time up to 180 min of incubation. The synthesis of constitutive alkaline phosphatase proceeds for some time in the cells that suffered lethal damages from γ-irradiation. A correction has been proposed for the calculation of the induction factor. 5 refs.; 11 figs

Unexpected Cartilage Phenotype in CD4-Cre-Conditional SOS-Deficient Mice.

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Guittard, Geoffrey; Gallardo, Devorah L; Li, Wenmei; Melis, Nicolas; Lui, Julian C; Kortum, Robert L; Shakarishvili, Nicholas G; Huh, Sunmee; Baron, Jeffrey; Weigert, Roberto; Kramer, Joshua A; Samelson, Lawrence E; Sommers, Connie L

2017-01-01

RAS signaling is central to many cellular processes and SOS proteins promote RAS activation. To investigate the role of SOS proteins in T cell biology, we crossed Sos1 f/f Sos2 -/- mice to CD4-Cre transgenic mice. We previously reported an effect of these mutations on T cell signaling and T cell migration. Unexpectedly, we observed nodules on the joints of greater than 90% of these mutant mice at 5 months of age, especially on the carpal joints. As the mice aged further, some also displayed joint stiffness, hind limb paralysis, and lameness. Histological analysis indicated that the abnormal growth in joints originated from dysplastic chondrocytes. Second harmonic generation imaging of the carpal nodules revealed that nodules were encased by rich collagen fibrous networks. Nodules formed in mice also deficient in RAG2, indicating that conventional T cells, which undergo rearrangement of the T cell antigen receptor, are not required for this phenotype. CD4-Cre expression in a subset of cells, either immune lineage cells (e.g., non-conventional T cells) or non-immune lineage cells (e.g., chondrocytes) likely mediates the dramatic phenotype observed in this study. Disruptions of genes in the RAS signaling pathway are especially likely to cause this phenotype. These results also serve as a cautionary tale to those intending to use CD4-Cre transgenic mice to specifically delete genes in conventional T cells.

Starvation, Together with the SOS Response, Mediates High Biofilm-Specific Tolerance to the Fluoroquinolone Ofloxacin

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Bernier, Steve P.; Lebeaux, David; DeFrancesco, Alicia S.; Valomon, Amandine; Soubigou, Guillaume; Coppée, Jean-Yves; Ghigo, Jean-Marc; Beloin, Christophe

2013-01-01

High levels of antibiotic tolerance are a hallmark of bacterial biofilms. In contrast to well-characterized inherited antibiotic resistance, molecular mechanisms leading to reversible and transient antibiotic tolerance displayed by biofilm bacteria are still poorly understood. The physiological heterogeneity of biofilms influences the formation of transient specialized subpopulations that may be more tolerant to antibiotics. In this study, we used random transposon mutagenesis to identify biofilm-specific tolerant mutants normally exhibited by subpopulations located in specialized niches of heterogeneous biofilms. Using Escherichia coli as a model organism, we demonstrated, through identification of amino acid auxotroph mutants, that starved biofilms exhibited significantly greater tolerance towards fluoroquinolone ofloxacin than their planktonic counterparts. We demonstrated that the biofilm-associated tolerance to ofloxacin was fully dependent on a functional SOS response upon starvation to both amino acids and carbon source and partially dependent on the stringent response upon leucine starvation. However, the biofilm-specific ofloxacin increased tolerance did not involve any of the SOS-induced toxin–antitoxin systems previously associated with formation of highly tolerant persisters. We further demonstrated that ofloxacin tolerance was induced as a function of biofilm age, which was dependent on the SOS response. Our results therefore show that the SOS stress response induced in heterogeneous and nutrient-deprived biofilm microenvironments is a molecular mechanism leading to biofilm-specific high tolerance to the fluoroquinolone ofloxacin. PMID:23300476

Managing the SOS Response for Enhanced CRISPR-Cas-Based Recombineering in E. coli through Transient Inhibition of Host RecA Activity.

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Moreb, Eirik Adim; Hoover, Benjamin; Yaseen, Adam; Valyasevi, Nisakorn; Roecker, Zoe; Menacho-Melgar, Romel; Lynch, Michael D

2017-12-15

Phage-derived "recombineering" methods are utilized for bacterial genome editing. Recombineering results in a heterogeneous population of modified and unmodified chromosomes, and therefore selection methods, such as CRISPR-Cas9, are required to select for edited clones. Cells can evade CRISPR-Cas-induced cell death through recA-mediated induction of the SOS response. The SOS response increases RecA dependent repair as well as mutation rates through induction of the umuDC error prone polymerase. As a result, CRISPR-Cas selection is more efficient in recA mutants. We report an approach to inhibiting the SOS response and RecA activity through the expression of a mutant dominant negative form of RecA, which incorporates into wild type RecA filaments and inhibits activity. Using a plasmid-based system in which Cas9 and recA mutants are coexpressed, we can achieve increased efficiency and consistency of CRISPR-Cas9-mediated selection and recombineering in E. coli, while reducing the induction of the SOS response. To date, this approach has been shown to be independent of recA genotype and host strain lineage. Using this system, we demonstrate increased CRISPR-Cas selection efficacy with over 10 000 guides covering the E. coli chromosome. The use of dominant negative RecA or homologues may be of broad use in bacterial CRISPR-Cas-based genome editing where the SOS pathways are present.

A fasciclin-like arabinogalactan-protein (FLA mutant of Arabidopsis thaliana, fla1, shows defects in shoot regeneration.

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Kim L Johnson

Full Text Available BACKGROUND: The fasciclin-like arabinogalactan-proteins (FLAs are an enigmatic class of 21 members within the larger family of arabinogalactan-proteins (AGPs in Arabidopsis thaliana. Located at the cell surface, in the cell wall/plasma membrane, they are implicated in many developmental roles yet their function remains largely undefined. Fasciclin (FAS domains are putative cell-adhesion domains found in extracellular matrix proteins of organisms from all kingdoms, but the juxtaposition of FAS domains with highly glycosylated AGP domains is unique to plants. Recent studies have started to elucidate the role of FLAs in Arabidopsis development. FLAs containing a single FAS domain are important for the integrity and elasticity of the plant cell wall matrix (FLA11 and FLA12 and FLA3 is involved in microspore development. FLA4/SOS5 with two FAS domains and two AGP domains has a role in maintaining proper cell expansion under salt stressed conditions. The role of other FLAs remains to be uncovered. METHOD/PRINCIPAL FINDINGS: Here we describe the characterisation of a T-DNA insertion mutant in the FLA1 gene (At5g55730. Under standard growth conditions fla1-1 mutants have no obvious phenotype. Based on gene expression studies, a putative role for FLA1 in callus induction was investigated and revealed that fla1-1 has a reduced ability to regenerate shoots in an in vitro shoot-induction assay. Analysis of FLA1p:GUS reporter lines show that FLA1 is expressed in several tissues including stomata, trichomes, the vasculature of leaves, the primary root tip and in lateral roots near the junction of the primary root. CONCLUSION: The results of the developmental expression of FLA1 and characterisation of the fla1 mutant support a role for FLA1 in the early events of lateral root development and shoot development in tissue culture, prior to cell-type specification.

A Modular SOS for Action Notation - Revisited

DEFF Research Database (Denmark)

Mosses, Peter David

A draft modular SOS for the new version of AN, referred to as AN-2, has been available since 2000. It is written in CASL and has been checked for well-formedness using CATS (CASL Tool Set). It appears to be significantly more accessible than the original SOS of AN-1. However, it now appears......-notation for the modular SOS rules. After discussing the issues, we look at some illustrative examples taken from an improved modular SOS of AN-2 (in preparation). We also look at the possibility of empirical testing of the modular SOS by a straightforward translation to Prolog....

Comparative study of SOS2 and a novel PMP3-1 gene expression in two sunflower (Helianthus annuus L.) lines differing in salt tolerance.

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Saadia, Mubshara; Jamil, Amer; Ashraf, Muhammad; Akram, Nudrat Aisha

2013-06-01

Gene expression pattern of two important regulatory proteins, salt overly sensitive 2 (SOS2) and plasma membrane protein 3-1 (PMP3-1), involved in ion homeostasis, was analyzed in two salinity-contrasting sunflower (Helianthus annuus L.) lines, Hysun-38 (salt tolerant) and S-278 (moderately salt tolerant). The pattern was studied at selected time intervals (24 h) under 150 mM NaCl treatment. Using reverse transcription PCR, SOS2 gene fragment was obtained from young leaf and root tissues of opposing lines while that for PMP3-1 was obtained only from young root tissues. Both tolerant and moderately tolerant lines showed a gradual increase in SOS2 expression in sunflower root tissues. Leaf tissues showed the gradually increasing pattern of SOS2 expression in tolerant plants as compared to that for moderately tolerant ones that showed a relatively lower level of expression for this gene. We found the highest level of PMP 3-1 expression in the roots of tolerant sunflower line at 6 and 12 h postsalinity treatment. The moderately tolerant line showed higher expression of PMP3-1 at 12 and 24 h after salt treatment. Overall, the expression of genes for both the regulator proteins varied significantly in the two sunflower lines differing in salinity tolerance.

Activation of Extracellular Signal-Regulated Kinase but Not of p38 Mitogen-Activated Protein Kinase Pathways in Lymphocytes Requires Allosteric Activation of SOS

Science.gov (United States)

Jun, Jesse E.; Yang, Ming; Chen, Hang; Chakraborty, Arup K.

2013-01-01

Thymocytes convert graded T cell receptor (TCR) signals into positive selection or deletion, and activation of extracellular signal-related kinase (ERK), p38, and Jun N-terminal protein kinase (JNK) mitogen-activated protein kinases (MAPKs) has been postulated to play a discriminatory role. Two families of Ras guanine nucleotide exchange factors (RasGEFs), SOS and RasGRP, activate Ras and the downstream RAF-MEK-ERK pathway. The pathways leading to lymphocyte p38 and JNK activation are less well defined. We previously described how RasGRP alone induces analog Ras-ERK activation while SOS and RasGRP cooperate to establish bimodal ERK activation. Here we employed computational modeling and biochemical experiments with model cell lines and thymocytes to show that TCR-induced ERK activation grows exponentially in thymocytes and that a W729E allosteric pocket mutant, SOS1, can only reconstitute analog ERK signaling. In agreement with RasGRP allosterically priming SOS, exponential ERK activation is severely decreased by pharmacological or genetic perturbation of the phospholipase Cγ (PLCγ)-diacylglycerol-RasGRP1 pathway. In contrast, p38 activation is not sharply thresholded and requires high-level TCR signal input. Rac and p38 activation depends on SOS1 expression but not allosteric activation. Based on computational predictions and experiments exploring whether SOS functions as a RacGEF or adaptor in Rac-p38 activation, we established that the presence of SOS1, but not its enzymatic activity, is critical for p38 activation. PMID:23589333

Specificity in suppression of SOS expression by recA4162 and uvrD303.

Science.gov (United States)

Massoni, Shawn C; Sandler, Steven J

2013-12-01

Detection and repair of DNA damage is essential in all organisms and depends on the ability of proteins recognizing and processing specific DNA substrates. In E. coli, the RecA protein forms a filament on single-stranded DNA (ssDNA) produced by DNA damage and induces the SOS response. Previous work has shown that one type of recA mutation (e.g., recA4162 (I298V)) and one type of uvrD mutation (e.g., uvrD303 (D403A, D404A)) can differentially decrease SOS expression depending on the type of inducing treatments (UV damage versus RecA mutants that constitutively express SOS). Here it is tested using other SOS inducing conditions if there is a general feature of ssDNA generated during these treatments that allows recA4162 and uvrD303 to decrease SOS expression. The SOS inducing conditions tested include growing cells containing temperature-sensitive DNA replication mutations (dnaE486, dnaG2903, dnaN159, dnaZ2016 (at 37°C)), a del(polA)501 mutation and induction of Double-Strand Breaks (DSBs). uvrD303 could decrease SOS expression under all conditions, while recA4162 could decrease SOS expression under all conditions except in the polA strain or when DSBs occur. It is hypothesized that recA4162 suppresses SOS expression best when the ssDNA occurs at a gap and that uvrD303 is able to decrease SOS expression when the ssDNA is either at a gap or when it is generated at a DSB (but does so better at a gap). Copyright © 2013 Elsevier B.V. All rights reserved.

SOS2-LIKE PROTEIN KINASE5, an SNF1-RELATED PROTEIN KINASE3-Type Protein Kinase, Is Important for Abscisic Acid Responses in Arabidopsis through Phosphorylation of ABSCISIC ACID-INSENSITIVE51[OPEN

Science.gov (United States)

Zhou, Xiaona; Hao, Hongmei; Zhang, Yuguo; Bai, Yili; Zhu, Wenbo; Qin, Yunxia; Yuan, Feifei; Zhao, Feiyi; Wang, Mengyao; Hu, Jingjiang; Xu, Hong; Guo, Aiguang; Zhao, Huixian; Zhao, Yang; Cao, Cuiling; Yang, Yongqing; Schumaker, Karen S.; Guo, Yan; Xie, Chang Gen

2015-01-01

Abscisic acid (ABA) plays an essential role in seed germination. In this study, we demonstrate that one SNF1-RELATED PROTEIN KINASE3-type protein kinase, SOS2-LIKE PROTEIN KINASE5 (PKS5), is involved in ABA signal transduction via the phosphorylation of an interacting protein, ABSCISIC ACID-INSENSITIVE5 (ABI5). We found that pks5-3 and pks5-4, two previously identified PKS5 superactive kinase mutants with point mutations in the PKS5 FISL/NAF (a conserved peptide that is necessary for interaction with SOS3 or SOS3-LIKE CALCIUM BINDING PROTEINs) motif and the kinase domain, respectively, are hypersensitive to ABA during seed germination. PKS5 was found to interact with ABI5 in yeast (Saccharomyces cerevisiae), and this interaction was further confirmed in planta using bimolecular fluorescence complementation. Genetic studies revealed that ABI5 is epistatic to PKS5. PKS5 phosphorylates a serine (Ser) residue at position 42 in ABI5 and regulates ABA-responsive gene expression. This phosphorylation was induced by ABA in vivo and transactivated ABI5. Expression of ABI5, in which Ser-42 was mutated to alanine, could not fully rescue the ABA-insensitive phenotypes of the abi5-8 and pks5-4abi5-8 mutants. In contrast, mutating Ser-42 to aspartate rescued the ABA insensitivity of these mutants. These data demonstrate that PKS5-mediated phosphorylation of ABI5 at Ser-42 is critical for the ABA regulation of seed germination and gene expression in Arabidopsis (Arabidopsis thaliana). PMID:25858916

[SOS-repair--60 years].

Science.gov (United States)

Zavil'gel'skiĭ, G B

2013-01-01

This review integrates 60 years of research on SOS-repair and SOS-mutagenesis in procaryotes and eucaryotes, from Jean Weigle experiment in 1953 year (mutagenesis of lambda bacteriophage in UV-irradiated bacteria) to the latest achievements in studying SOS-mutagenesis on all living organisms--Eukarya, Archaea and Bacteria. A key role in establishing of a biochemical basis for SOS-mutagenesis belonges to the finding in 1998-1999 years that specific error-prone DNA polymerases (PolV and others) catalysed translesion synthesis on damaged DNA. This review focuses on recent studies addressing the new models for SOS-induced mutagenesis in Escherichia coli and Home sapiens cells.

NOAA NDBC SOS - waves

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have waves data. Because of the nature of SOS requests, requests for data...

DnaC inactivation in Escherichia coli K-12 induces the SOS response and expression of nucleotide biosynthesis genes

DEFF Research Database (Denmark)

Løbner-Olesen, Anders; Slominska-Wojewodzka, Monika; Hansen, Flemming G.

2008-01-01

Background: Initiation of chromosome replication in E. coli requires the DnaA and DnaC proteins and conditionally-lethal dnaA and dnaC mutants are often used to synchronize cell populations. Methodology/Principal Findings: DNA microarrays were used to measure mRNA steady-state levels in initiatio......C genes was increased at the non-permissive temperature in the respective mutant strains indicating auto-regulation of both genes. Induction of the SOS regulon was observed in dnaC2 cells at 38 degrees C and 42 degrees C. Flow cytometric analysis revealed that dnaC2 mutant cells at non......-permissive temperature had completed the early stages of chromosome replication initiation. Conclusion/Significance: We suggest that in dnaC2 cells the SOS response is triggered by persistent open-complex formation at oriC and/or by arrested forks that require DnaC for replication restart....

Arabidopsis thaliana ggt1 photorespiratory mutants maintain leaf carbon/nitrogen balance by reducing RuBisCO content and plant growth.

Science.gov (United States)

Dellero, Younès; Lamothe-Sibold, Marlène; Jossier, Mathieu; Hodges, Michael

2015-09-01

Metabolic and physiological analyses of glutamate:glyoxylate aminotransferase 1 (GGT1) mutants were performed at the global leaf scale to elucidate the mechanisms involved in their photorespiratory growth phenotype. Air-grown ggt1 mutants showed retarded growth and development, that was not observed at high CO2 (3000 μL L(-1) ). When compared to wild-type (WT) plants, air-grown ggt1 plants exhibited glyoxylate accumulation, global changes in amino acid amounts including a decrease in serine content, lower organic acid levels, and modified ATP/ADP and NADP(+) /NADPH ratios. When compared to WT plants, their net CO2 assimilation rates (An ) were 50% lower and this mirrored decreases in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) contents. High CO2 -grown ggt1 plants transferred to air revealed a rapid decrease of An and photosynthetic electron transfer rate while maintaining a high energetic state. Short-term (a night period and 4 h of light) transferred ggt1 leaves accumulated glyoxylate and exhibited low serine contents, while other amino acid levels were not modified. RuBisCO content, activity and activation state were not altered after a short-term transfer while the ATP/ADP ratio was lowered in ggt1 rosettes. However, plant growth and RuBisCO levels were both reduced in ggt1 leaves after a long-term (12 days) acclimation to air from high CO2 when compared to WT plants. The data are discussed with respect to a reduced photorespiratory carbon recycling in the mutants. It is proposed that the low An limits nitrogen-assimilation, this decreases leaf RuBisCO content until plants attain a new homeostatic state that maintains a constant C/N balance and leads to smaller, slower growing plants. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

SoS contract verification using statistical model checking

Directory of Open Access Journals (Sweden)

Alessandro Mignogna

2013-11-01

Full Text Available Exhaustive formal verification for systems of systems (SoS is impractical and cannot be applied on a large scale. In this paper we propose to use statistical model checking for efficient verification of SoS. We address three relevant aspects for systems of systems: 1 the model of the SoS, which includes stochastic aspects; 2 the formalization of the SoS requirements in the form of contracts; 3 the tool-chain to support statistical model checking for SoS. We adapt the SMC technique for application to heterogeneous SoS. We extend the UPDM/SysML specification language to express the SoS requirements that the implemented strategies over the SoS must satisfy. The requirements are specified with a new contract language specifically designed for SoS, targeting a high-level English- pattern language, but relying on an accurate semantics given by the standard temporal logics. The contracts are verified against the UPDM/SysML specification using the Statistical Model Checker (SMC PLASMA combined with the simulation engine DESYRE, which integrates heterogeneous behavioral models through the functional mock-up interface (FMI standard. The tool-chain allows computing an estimation of the satisfiability of the contracts by the SoS. The results help the system architect to trade-off different solutions to guide the evolution of the SoS.

A novel two-step method for screening shade tolerant mutant plants via dwarfism

Directory of Open Access Journals (Sweden)

Wei Li

2016-10-01

Full Text Available When subjected to shade, plants undergo rapid shoot elongation, which often makes them more prone to disease and mechanical damage. Shade-tolerant plants can be difficult to breed; however, they offer a substantial benefit over other varieties in low-light areas. Although perennial ryegrass (Lolium perenne L. is a popular species of turf grasses because of their good appearance and fast establishment, the plant normally does not perform well under shade conditions. It has been reported that, in turfgrass, induced dwarfism can enhance shade tolerance. Here we describe a two-step procedure for isolating shade tolerant mutants of perennial ryegrass by first screening for dominant dwarf mutants, and then screening dwarf plants for shade tolerance. The two-step screening process to isolate shade tolerant mutants can be done efficiently with limited space at early seedling stages, which enables quick and efficient isolation of shade tolerant mutants, and thus facilitates development of shade tolerant new cultivars of turfgrasses. Using the method, we isolated 136 dwarf mutants from 300,000 mutagenized seeds, with 65 being shade tolerant (0.022%. When screened directly for shade tolerance, we recovered only four mutants from a population of 150,000 (0.003% mutagenized seeds. One shade tolerant mutant, shadow-1, was characterized in detail. In addition to dwarfism, shadow-1 and its sexual progeny displayed high degrees of tolerance to both natural and artificial shade. We showed that endogenous gibberellin (GA content in shadow-1 was higher than wild-type controls, and shadow-1 was also partially GA insensitive. Our novel, simple and effective two-step screening method should be applicable to breeding shade tolerant cultivars of turfgrasses, ground covers, and other economically important crop plants that can be used under canopies of existing vegetation to increase productivity per unit area of land.

Dominant negative umuD mutations decreasing RecA-mediated cleavage suggest roles for intact UmuD in modulation of SOS mutagenesis

International Nuclear Information System (INIS)

Battista, J.R.; Ohta, Toshihiro; Nohmi, Takehiko; Sun, W.; Walker, G.C.

1990-01-01

The products of the SOS-regulated umuDC operon are required for most UV and chemical mutagenesis in Escherichia coli. The UmuD protein shares homology with a family of proteins that includes LexA and several bacteriophage repressors. UmuD is posttranslationally activated for its role n mutagenesis by a RecA-mediated proteolytic cleavage that yields UmuD'. A set of missense mutants of umuD was isolated and shown to encode mutant UmuD proteins that are deficient in RecA-mediated cleavage in vivo. Most of these mutations are dominant to umuD + with respect to UV mutagenesis yet do not interfere with SOS induction. Although both UmuD and UmuD' form homodimers, the authors provide evidence that they preferentially form heterodimers. The relationship of UmuD to LexA, λ repressor, and other members of the family of proteins is discussed and possible roles intact UmuD in modulating SOS mutagenesis are discussed

Survival and SOS response induction in ultraviolet B irradiated Escherichia coli cells with defective repair mechanisms.

Science.gov (United States)

Prada Medina, Cesar Augusto; Aristizabal Tessmer, Elke Tatjana; Quintero Ruiz, Nathalia; Serment-Guerrero, Jorge; Fuentes, Jorge Luis

2016-06-01

Purpose In this paper, the contribution of different genes involved in DNA repair for both survival and SOS induction in Escherichia coli mutants exposed to ultraviolet B radiation (UVB, [wavelength range 280-315 nm]) was evaluated. Materials and methods E. coli strains defective in uvrA, oxyR, recO, recN, recJ, exoX, recB, recD or xonA genes were used to determine cell survival. All strains also had the genetic sulA::lacZ fusion, which allowed for the quantification of SOS induction through the SOS Chromotest. Results Five gene products were particularly important for survival, as follows: UvrA > RecB > RecO > RecJ > XonA. Strains defective in uvrA and recJ genes showed elevated SOS induction compared with the wild type, which remained stable for up to 240 min after UVB-irradiation. In addition, E. coli strains carrying the recO or recN mutation showed no SOS induction. Conclusions The nucleotide excision and DNA recombination pathways were equally used to repair UVB-induced DNA damage in E. coli cells. The sulA gene was not turned off in strains defective in UvrA and RecJ. RecO protein was essential for processing DNA damage prior to SOS induction. In this study, the roles of DNA repair proteins and their contributions to the mechanisms that induce SOS genes in E. coli are proposed.

Evelin Ilves avas SOS Lasteküla

Index Scriptorium Estoniae

2010-01-01

SOS Lasteküla patroon proua Evelin Ilves avas 1. juunil 2010 Põltsamaal Eesti teise SOS Lasteküla. Presidendi abikaasa tõi kingiks õunapuuistikuid ja lasteraamatuid. Ilmunud ka: Eesti Päevaleht 2. juuni 2010, lk. 4

The Arabidopsis mutant iop1 exhibits induced over-expression of the plant defensin gene PDF1.2 and enhanced pathogen resistance

NARCIS (Netherlands)

Penninckx, I.A.M.A.; Eggermont, K.; Schenk, P.M.; Ackerveken, van den G.; Cammue, B.P.A.; Thomma, B.P.H.J.

2003-01-01

Jasmonate and ethylene are concomitantly involved in the induction of the Arabidopsis plant defensin gene PDF1.2. To define genes in the signal transduction pathway leading to the induction of PDF1.2, we screened for mutants with induced over-expression of a β-glucuronidase reporter, under the

Monitoring Ras Interactions with the Nucleotide Exchange Factor Son of Sevenless (Sos) Using Site-specific NMR Reporter Signals and Intrinsic Fluorescence*

Science.gov (United States)

Vo, Uybach; Vajpai, Navratna; Flavell, Liz; Bobby, Romel; Breeze, Alexander L.; Embrey, Kevin J.; Golovanov, Alexander P.

2016-01-01

The activity of Ras is controlled by the interconversion between GTP- and GDP-bound forms partly regulated by the binding of the guanine nucleotide exchange factor Son of Sevenless (Sos). The details of Sos binding, leading to nucleotide exchange and subsequent dissociation of the complex, are not completely understood. Here, we used uniformly 15N-labeled Ras as well as [13C]methyl-Met,Ile-labeled Sos for observing site-specific details of Ras-Sos interactions in solution. Binding of various forms of Ras (loaded with GDP and mimics of GTP or nucleotide-free) at the allosteric and catalytic sites of Sos was comprehensively characterized by monitoring signal perturbations in the NMR spectra. The overall affinity of binding between these protein variants as well as their selected functional mutants was also investigated using intrinsic fluorescence. The data support a positive feedback activation of Sos by Ras·GTP with Ras·GTP binding as a substrate for the catalytic site of activated Sos more weakly than Ras·GDP, suggesting that Sos should actively promote unidirectional GDP → GTP exchange on Ras in preference of passive homonucleotide exchange. Ras·GDP weakly binds to the catalytic but not to the allosteric site of Sos. This confirms that Ras·GDP cannot properly activate Sos at the allosteric site. The novel site-specific assay described may be useful for design of drugs aimed at perturbing Ras-Sos interactions. PMID:26565026

Vesiculation from Pseudomonas aeruginosa under SOS.

Science.gov (United States)

Maredia, Reshma; Devineni, Navya; Lentz, Peter; Dallo, Shatha F; Yu, Jiehjuen; Guentzel, Neal; Chambers, James; Arulanandam, Bernard; Haskins, William E; Weitao, Tao

2012-01-01

Bacterial infections can be aggravated by antibiotic treatment that induces SOS response and vesiculation. This leads to a hypothesis concerning association of SOS with vesiculation. To test it, we conducted multiple analyses of outer membrane vesicles (OMVs) produced from the Pseudomonas aeruginosa wild type in which SOS is induced by ciprofloxacin and from the LexA noncleavable (lexAN) strain in which SOS is repressed. The levels of OMV proteins, lipids, and cytotoxicity increased for both the treated strains, demonstrating vesiculation stimulation by the antibiotic treatment. However, the further increase was suppressed in the lexAN strains, suggesting the SOS involvement. Obviously, the stimulated vesiculation is attributed by both SOS-related and unrelated factors. OMV subproteomic analysis was performed to examine these factors, which reflected the OMV-mediated cytotoxicity and the physiology of the vesiculating cells under treatment and SOS. Thus, SOS plays a role in the vesiculation stimulation that contributes to cytotoxicity.

Characterization of the snowy cotyledon 1 mutant of Arabidopsis thaliana: the impact of chloroplast elongation factor G on chloroplast development and plant vitality.

Science.gov (United States)

Albrecht, Verónica; Ingenfeld, Anke; Apel, Klaus

2006-03-01

During seedling development chloroplast formation marks the transition from heterotrophic to autotrophic growth. The development and activity of chloroplasts may differ in cotyledons that initially serve as a storage organ and true leaves whose primary function is photosynthesis. A genetic screen was used for the identification of genes that affect selectively chloroplast function in cotyledons of Arabidopsis thaliana. Several mutants exhibiting pale cotyledons and green true leaves were isolated and dubbed snowy cotyledon (sco). One of the mutants, sco1, was characterized in more detail. The mutated gene was identified using map-based cloning. The mutant contains a point mutation in a gene encoding the chloroplast elongation factor G, leading to an amino acid exchange within the predicted 70S ribosome-binding domain. The mutation results in a delay in the onset of germination. At this early developmental stage embryos still contain undifferentiated proplastids, whose proper function seems necessary for seed germination. In light-grown sco1 seedlings the greening of cotyledons is severely impaired, whereas the following true leaves develop normally as in wild-type plants. Despite this apparent similarity of chloroplast development in true leaves of mutant and wild-type plants various aspects of mature plant development are also affected by the sco1 mutation such as the onset of flowering, the growth rate, and seed production. The onset of senescence in the mutant and the wild-type plants occurs, however, at the same time, suggesting that in the mutant this particular developmental step does not seem to suffer from reduced protein translation efficiency in chloroplasts.

The complex between SOS3 and SOS2 regulatory domain from Arabidopsis thaliana: cloning, expression, purification, crystallization and preliminary X-ray analysis

Energy Technology Data Exchange (ETDEWEB)

Sánchez-Barrena, María José; Moreno-Pérez, Sandra; Angulo, Iván; Martínez-Ripoll, Martín; Albert, Armando, E-mail: xalbert@iqfr.csic.es [Grupo de Cristalografía Macromolecular y Biología Estructural, Instituto de Química Física ‘Rocasolano’, Consejo Superior de Investigaciones Científicas, Serrano 119, E-28006 Madrid (Spain)

2007-07-01

Recombinant SOS3 and SOS2 regulatory domain from A. thaliana have been coexpressed in E. coli, purified and crystallized by the hanging-drop vapour-diffusion method. An X-ray data set has been collected at 2.0 Å resolution. The salt-tolerance genes SOS3 (salt overly sensitive 3) and SOS2 (salt overly sensitive 2) regulatory domain of Arabidopsis thaliana were cloned into a polycistronic plasmid and the protein complex was expressed in Escherichia coli, allowing purification to homogeneity in three chromatographic steps. Crystals were grown using vapour-diffusion techniques. The crystals belonged to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 44.14, b = 57.39, c = 141.90 Å.

Specificity determinants for autoproteolysis of LexA, a key regulator of bacterial SOS mutagenesis.

Science.gov (United States)

Mo, Charlie Y; Birdwell, L Dillon; Kohli, Rahul M

2014-05-20

Bacteria utilize the tightly regulated stress response (SOS) pathway to respond to a variety of genotoxic agents, including antimicrobials. Activation of the SOS response is regulated by a key repressor-protease, LexA, which undergoes autoproteolysis in the setting of stress, resulting in derepression of SOS genes. Remarkably, genetic inactivation of LexA's self-cleavage activity significantly decreases acquired antibiotic resistance in infection models and renders bacteria hypersensitive to traditional antibiotics, suggesting that a mechanistic study of LexA could help inform its viability as a novel target for combating acquired drug resistance. Despite structural insights into LexA, a detailed knowledge of the enzyme's protease specificity is lacking. Here, we employ saturation and positional scanning mutagenesis on LexA's internal cleavage region to analyze >140 mutants and generate a comprehensive specificity profile of LexA from the human pathogen Pseudomonas aeruginosa (LexAPa). We find that the LexAPa active site possesses a unique mode of substrate recognition. Positions P1-P3 prefer small hydrophobic residues that suggest specific contacts with the active site, while positions P5 and P1' show a preference for flexible glycine residues that may facilitate the conformational change that permits autoproteolysis. We further show that stabilizing the β-turn within the cleavage region enhances LexA autoproteolytic activity. Finally, we identify permissive positions flanking the scissile bond (P4 and P2') that are tolerant to extensive mutagenesis. Our studies shed light on the active site architecture of the LexA autoprotease and provide insights that may inform the design of probes of the SOS pathway.

Glutathione S-transferase M1-null genotype as risk factor for SOS in oxaliplatin-treated patients with metastatic colorectal cancer.

Science.gov (United States)

Vreuls, C P H; Olde Damink, S W M; Koek, G H; Winstanley, A; Wisse, E; Cloots, R H E; van den Broek, M A J; Dejong, C H C; Bosman, F T; Driessen, A

2013-02-19

Oxaliplatin is used as a neo-adjuvant therapy in hepatic colorectal carcinoma metastasis. This treatment has significant side effects, as oxaliplatin is toxic to the sinusoidal endothelial cells and can induce sinusoidal obstruction syndrome (SOS), which is related to decreased overall survival. Glutathione has an important role in the defence system, catalysed by glutathione S-transferase (GST), including two non-enzyme producing polymorphisms (GSTM1-null and GSTT1-null). We hypothesise that patients with a non-enzyme producing polymorphism have a higher risk of developing toxic injury owing to oxaliplatin. In the nontumour-bearing liver, the presence of SOS was studied histopathologically. The genotype was determined by a semi-nested PCR. Thirty-two of the 55 (58%) patients showed SOS lesions, consisting of 27% mild, 22% moderate and 9% severe lesions. The GSTM1-null genotype was present in 25 of the 55 (46%). Multivariate analysis showed that the GSTM1-null genotype significantly correlated with the presence of (moderate-severe) SOS (P=0.026). The GSTM1-null genotype is an independent risk factor for SOS. This finding allows us, in association with other risk factors, to conceive a potential risk profile predicting whether the patient is at risk of developing SOS, before starting oxaliplatin, and subsequently might result in adjustment of treatment.

Monitoring Ras Interactions with the Nucleotide Exchange Factor Son of Sevenless (Sos) Using Site-specific NMR Reporter Signals and Intrinsic Fluorescence.

Science.gov (United States)

Vo, Uybach; Vajpai, Navratna; Flavell, Liz; Bobby, Romel; Breeze, Alexander L; Embrey, Kevin J; Golovanov, Alexander P

2016-01-22

The activity of Ras is controlled by the interconversion between GTP- and GDP-bound forms partly regulated by the binding of the guanine nucleotide exchange factor Son of Sevenless (Sos). The details of Sos binding, leading to nucleotide exchange and subsequent dissociation of the complex, are not completely understood. Here, we used uniformly (15)N-labeled Ras as well as [(13)C]methyl-Met,Ile-labeled Sos for observing site-specific details of Ras-Sos interactions in solution. Binding of various forms of Ras (loaded with GDP and mimics of GTP or nucleotide-free) at the allosteric and catalytic sites of Sos was comprehensively characterized by monitoring signal perturbations in the NMR spectra. The overall affinity of binding between these protein variants as well as their selected functional mutants was also investigated using intrinsic fluorescence. The data support a positive feedback activation of Sos by Ras·GTP with Ras·GTP binding as a substrate for the catalytic site of activated Sos more weakly than Ras·GDP, suggesting that Sos should actively promote unidirectional GDP → GTP exchange on Ras in preference of passive homonucleotide exchange. Ras·GDP weakly binds to the catalytic but not to the allosteric site of Sos. This confirms that Ras·GDP cannot properly activate Sos at the allosteric site. The novel site-specific assay described may be useful for design of drugs aimed at perturbing Ras-Sos interactions. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Expansion of the SOS regulon of Vibrio cholerae through extensive transcriptome analysis and experimental validation.

Science.gov (United States)

Krin, Evelyne; Pierlé, Sebastian Aguilar; Sismeiro, Odile; Jagla, Bernd; Dillies, Marie-Agnès; Varet, Hugo; Irazoki, Oihane; Campoy, Susana; Rouy, Zoé; Cruveiller, Stéphane; Médigue, Claudine; Coppée, Jean-Yves; Mazel, Didier

2018-05-21

The SOS response is an almost ubiquitous response of cells to genotoxic stresses. The full complement of genes in the SOS regulon for Vibrio species has only been addressed through bioinformatic analyses predicting LexA binding box consensus and in vitro validation. Here, we perform whole transcriptome sequencing from Vibrio cholerae treated with mitomycin C as an SOS inducer to characterize the SOS regulon and other pathways affected by this treatment. Comprehensive transcriptional profiling allowed us to define the full landscape of promoters and transcripts active in V. cholerae. We performed extensive transcription start site (TSS) mapping as well as detection/quantification of the coding and non-coding RNA (ncRNA) repertoire in strain N16961. To improve TSS detection, we developed a new technique to treat RNA extracted from cells grown in various conditions. This allowed for identification of 3078 TSSs with an average 5'UTR of 116 nucleotides, and peak distribution between 16 and 64 nucleotides; as well as 629 ncRNAs. Mitomycin C treatment induced transcription of 737 genes and 28 ncRNAs at least 2 fold, while it repressed 231 genes and 17 ncRNAs. Data analysis revealed that in addition to the core genes known to integrate the SOS regulon, several metabolic pathways were induced. This study allowed for expansion of the Vibrio SOS regulon, as twelve genes (ubiEJB, tatABC, smpA, cep, VC0091, VC1190, VC1369-1370) were found to be co-induced with their adjacent canonical SOS regulon gene(s), through transcriptional read-through. Characterization of UV and mitomycin C susceptibility for mutants of these newly identified SOS regulon genes and other highly induced genes and ncRNAs confirmed their role in DNA damage rescue and protection. We show that genotoxic stress induces a pervasive transcriptional response, affecting almost 20% of the V. cholerae genes. We also demonstrate that the SOS regulon is larger than previously known, and its syntenic organization is

NOAA NDBC SOS, 2007-present, currents

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have currents data. Because of the nature of SOS requests, requests for...

NOAA NDBC SOS, 2006-present, winds

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have winds data. Because of the nature of SOS requests, requests for data...

The research progress on plant mutant germplasm resources in China

International Nuclear Information System (INIS)

He Cexi; Ji Linzhen; Zhao Shirong

1991-07-01

Mutants induced by nuclear radiation or other mutagens are new artificial germplasm resources. Some mutants have been applied in plant breeding and great achievements have been reached. The status and progress on the collection, identification and utilization of mutants in China are introduced. A proposal for developing mutant germplasm resources with good agronomic characters is suggested

RUNX1 positively regulates the ErbB2/HER2 signaling pathway through modulating SOS1 expression in gastric cancer cells.

Science.gov (United States)

Mitsuda, Yoshihide; Morita, Ken; Kashiwazaki, Gengo; Taniguchi, Junichi; Bando, Toshikazu; Obara, Moeka; Hirata, Masahiro; Kataoka, Tatsuki R; Muto, Manabu; Kaneda, Yasufumi; Nakahata, Tatsutoshi; Liu, Pu Paul; Adachi, Souichi; Sugiyama, Hiroshi; Kamikubo, Yasuhiko

2018-04-23

The dual function of runt-related transcriptional factor 1 (RUNX1) as an oncogene or oncosuppressor has been extensively studied in various malignancies, yet its role in gastric cancer remains elusive. Up-regulation of the ErbB2/HER2 signaling pathway is frequently-encountered in gastric cancer and contributes to the maintenance of these cancer cells. This signaling cascade is partly mediated by son of sevenless homolog (SOS) family, which function as adaptor proteins in the RTK cascades. Herein we report that RUNX1 regulates the ErbB2/HER2 signaling pathway in gastric cancer cells through transactivating SOS1 expression, rendering itself an ideal target in anti-tumor strategy toward this cancer. Mechanistically, RUNX1 interacts with the RUNX1 binding DNA sequence located in SOS1 promoter and positively regulates it. Knockdown of RUNX1 led to the decreased expression of SOS1 as well as dephosphorylation of ErbB2/HER2, subsequently suppressed the proliferation of gastric cancer cells. We also found that our novel RUNX inhibitor (Chb-M') consistently led to the deactivation of the ErbB2/HER2 signaling pathway and was effective against several gastric cancer cell lines. Taken together, our work identified a novel interaction of RUNX1 and the ErbB2/HER2 signaling pathway in gastric cancer, which can potentially be exploited in the management of this malignancy.

Ras activation by SOS

DEFF Research Database (Denmark)

Iversen, Lars; Tu, Hsiung-Lin; Lin, Wan-Chen

2014-01-01

Activation of the small guanosine triphosphatase H-Ras by the exchange factor Son of Sevenless (SOS) is an important hub for signal transduction. Multiple layers of regulation, through protein and membrane interactions, govern activity of SOS. We characterized the specific activity of individual ...

The Arabidopsis thiamin-deficient mutant pale green1 lacks thiamin monophosphate phosphatase of the vitamin B1 biosynthesis pathway.

Science.gov (United States)

Hsieh, Wei-Yu; Liao, Jo-Chien; Wang, Hsin-Tzu; Hung, Tzu-Huan; Tseng, Ching-Chih; Chung, Tsui-Yun; Hsieh, Ming-Hsiun

2017-07-01

Thiamin diphosphate (TPP, vitamin B 1 ) is an essential coenzyme present in all organisms. Animals obtain TPP from their diets, but plants synthesize TPPde novo. We isolated and characterized an Arabidopsis pale green1 (pale1) mutant that contained higher concentrations of thiamin monophosphate (TMP) and less thiamin and TPP than the wild type. Supplementation with thiamin, but not the thiazole and pyrimidine precursors, rescued the mutant phenotype, indicating that the pale1 mutant is a thiamin-deficient mutant. Map-based cloning and whole-genome sequencing revealed that the pale1 mutant has a mutation in At5g32470 encoding a TMP phosphatase of the TPP biosynthesis pathway. We further confirmed that the mutation of At5g32470 is responsible for the mutant phenotypes by complementing the pale1 mutant with constructs overexpressing full-length At5g32470. Most plant TPP biosynthetic enzymes are located in the chloroplasts and cytosol, but At5g32470-GFP localized to the mitochondrion of the root, hypocotyl, mesophyll and guard cells of the 35S:At5g32470-GFP complemented plants. The subcellular localization of a functional TMP phosphatase suggests that the complete vitamin B1 biosynthesis pathway may involve the chloroplasts, mitochondria and cytosol in plants. Analysis of PALE1 promoter-uidA activity revealed that PALE1 is mainly expressed in vascular tissues of Arabidopsis seedlings. Quantitative RT-PCR analysis of TPP biosynthesis genes and genes encoding the TPP-dependent enzymes pyruvate dehydrogenase, α-ketoglutarate dehydrogenase and transketolase revealed that the transcript levels of these genes were upregulated in the pale1 mutant. These results suggest that endogenous levels of TPP may affect the expression of genes involved in TPP biosynthesis and TPP-dependent enzymes. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Competitive fitness during feast and famine: how SOS DNA polymerases influence physiology and evolution in Escherichia coli.

Science.gov (United States)

Corzett, Christopher H; Goodman, Myron F; Finkel, Steven E

2013-06-01

Escherichia coli DNA polymerases (Pol) II, IV, and V serve dual roles by facilitating efficient translesion DNA synthesis while simultaneously introducing genetic variation that can promote adaptive evolution. Here we show that these alternative polymerases are induced as cells transition from exponential to long-term stationary-phase growth in the absence of induction of the SOS regulon by external agents that damage DNA. By monitoring the relative fitness of isogenic mutant strains expressing only one alternative polymerase over time, spanning hours to weeks, we establish distinct growth phase-dependent hierarchies of polymerase mutant strain competitiveness. Pol II confers a significant physiological advantage by facilitating efficient replication and creating genetic diversity during periods of rapid growth. Pol IV and Pol V make the largest contributions to evolutionary fitness during long-term stationary phase. Consistent with their roles providing both a physiological and an adaptive advantage during stationary phase, the expression patterns of all three SOS polymerases change during the transition from log phase to long-term stationary phase. Compared to the alternative polymerases, Pol III transcription dominates during mid-exponential phase; however, its abundance decreases to SOS induction by exogenous agents and indicate that cell populations require appropriate expression of all three alternative DNA polymerases during exponential, stationary, and long-term stationary phases to attain optimal fitness and undergo adaptive evolution.

Characterization of the Burkholderia thailandensis SOS response by using whole-transcriptome shotgun sequencing.

Science.gov (United States)

Ulrich, Ricky L; Deshazer, David; Kenny, Tara A; Ulrich, Melanie P; Moravusova, Anna; Opperman, Timothy; Bavari, Sina; Bowlin, Terry L; Moir, Donald T; Panchal, Rekha G

2013-10-01

The bacterial SOS response is a well-characterized regulatory network encoded by most prokaryotic bacterial species and is involved in DNA repair. In addition to nucleic acid repair, the SOS response is involved in pathogenicity, stress-induced mutagenesis, and the emergence and dissemination of antibiotic resistance. Using high-throughput sequencing technology (SOLiD RNA-Seq), we analyzed the Burkholderia thailandensis global SOS response to the fluoroquinolone antibiotic, ciprofloxacin (CIP), and the DNA-damaging chemical, mitomycin C (MMC). We demonstrate that a B. thailandensis recA mutant (RU0643) is ∼4-fold more sensitive to CIP in contrast to the parental strain B. thailandensis DW503. Our RNA-Seq results show that CIP and MMC treatment (P SOS response were induced and include lexA, uvrA, dnaE, dinB, recX, and recA. At the genome-wide level, we found an overall decrease in gene expression, especially for genes involved in amino acid and carbohydrate transport and metabolism, following both CIP and MMC exposure. Interestingly, we observed the upregulation of several genes involved in bacterial motility and enhanced transcription of a B. thailandensis genomic island encoding a Siphoviridae bacteriophage designated E264. Using B. thailandensis plaque assays and PCR with B. mallei ATCC 23344 as the host, we demonstrate that CIP and MMC exposure in B. thailandensis DW503 induces the transcription and translation of viable bacteriophage in a RecA-dependent manner. This is the first report of the SOS response in Burkholderia spp. to DNA-damaging agents. We have identified both common and unique adaptive responses of B. thailandensis to chemical stress and DNA damage.

The SOS Response Master Regulator LexA Regulates the Gene Transfer Agent of Rhodobacter capsulatus and Represses Transcription of the Signal Transduction Protein CckA.

Science.gov (United States)

Kuchinski, Kevin S; Brimacombe, Cedric A; Westbye, Alexander B; Ding, Hao; Beatty, J Thomas

2016-02-01

The gene transfer agent of Rhodobacter capsulatus (RcGTA) is a genetic exchange element that combines central aspects of bacteriophage-mediated transduction and natural transformation. RcGTA particles resemble a small double-stranded DNA bacteriophage, package random ∼4-kb fragments of the producing cell genome, and are released from a subpopulation (SOS response in many bacteria, as a regulator of RcGTA activity. Deletion of the lexA gene resulted in the abolition of detectable RcGTA production and an ∼10-fold reduction in recipient capability. A search for SOS box sequences in the R. capsulatus genome sequence identified a number of putative binding sites located 5' of typical SOS response coding sequences and also 5' of the RcGTA regulatory gene cckA, which encodes a hybrid histidine kinase homolog. Expression of cckA was increased >5-fold in the lexA mutant, and a lexA cckA double mutant was found to have the same phenotype as a ΔcckA single mutant in terms of RcGTA production. The data indicate that LexA is required for RcGTA production and maximal recipient capability and that the RcGTA-deficient phenotype of the lexA mutant is largely due to the overexpression of cckA. This work describes an unusual phenotype of a lexA mutant of the alphaproteobacterium Rhodobacter capsulatus in respect to the phage transduction-like genetic exchange carried out by the R. capsulatus gene transfer agent (RcGTA). Instead of the expected SOS response characteristic of prophage induction, this lexA mutation not only abolishes the production of RcGTA particles but also impairs the ability of cells to receive RcGTA-borne genes. The data show that, despite an apparent evolutionary relationship to lambdoid phages, the regulation of RcGTA gene expression differs radically. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Effects of Light Intensity on Development and Chlorophyll Content in the Arabidopsis Mutant Plants with Defects in Photosynthesis

Directory of Open Access Journals (Sweden)

E.Yu. Garnik

2015-12-01

Full Text Available The developmental stages and adaptability to different light intensity (150 µmol*m-2*s-1 and 100 µmol*m-2*s-1 in Arabidopsis mutant lines with defects of photosynthetic apparatus were analyzed. Plant development in the mutant lines depended on the light intensity to varying degrees. Lines ch1-1 (lack of the chlorophyllide a oxygenase and rtn16 (decreased chlorophyll a and b amounts were the most susceptible to the light decrease. No one of the investigated lines demonstrated chlorophyll a/b rate alteration under the different light conditions. The depleted chlorophyll content has had the major effect on the mutant plants development under the different light conditions. The different chlorophyll a/b rate correlated with the different adaptability of mutant plants to low light.

Sinusoidal obstruction syndrome (SOS) related to chemotherapy for colorectal liver metastases: factors predictive of severe SOS lesions and protective effect of bevacizumab.

Science.gov (United States)

Hubert, Catherine; Sempoux, Christine; Humblet, Yves; van den Eynde, Marc; Zech, Francis; Leclercq, Isabelle; Gigot, Jean-François

2013-11-01

The most frequent presentation of chemotherapy-related toxicity in colorectal liver metastases (CRLM) is sinusoidal obstruction syndrome (SOS). The purpose of the present study was to identify preoperative factors predictive of SOS and to establish associations between type of chemotherapy and severity of SOS. A retrospective study was carried out in a tertiary academic referral hospital. Patients suffering from CRLM who had undergone resection of at least one liver segment were included. Grading of SOS on the non-tumoral liver parenchyma was accomplished according to the Rubbia-Brandt criteria. A total of 151 patients were enrolled and divided into four groups according to the severity of SOS (grades 0-3). Multivariate analysis identified oxaliplatin and 5-fluorouracil as chemotherapeutic agents responsible for severe SOS lesions (P SOS lesions (P = 0.005). Univariate analysis identified the score on the aspartate aminotransferase : platelets ratio index (APRI) as the most significant biological factor predictive of severe SOS lesions. Splenomegaly is also significantly associated with the occurrence of severe SOS lesions. The APRI score and splenomegaly are effective as factors predictive of SOS. Bevacizumab has a protective effect against SOS. © 2013 International Hepato-Pancreato-Biliary Association.

Effect of SOS-induced levels of imuABC on spontaneous and damage-induced mutagenesis in Caulobacter crescentus.

Science.gov (United States)

Alves, Ingrid R; Lima-Noronha, Marco A; Silva, Larissa G; Fernández-Silva, Frank S; Freitas, Aline Luiza D; Marques, Marilis V; Galhardo, Rodrigo S

2017-11-01

imuABC (imuAB dnaE2) genes are responsible for SOS-mutagenesis in Caulobacter crescentus and other bacterial species devoid of umuDC. In this work, we have constructed operator-constitutive mutants of the imuABC operon. We used this genetic tool to investigate the effect of SOS-induced levels of these genes upon both spontaneous and damage-induced mutagenesis. We showed that constitutive expression of imuABC does not increase spontaneous or damage-induced mutagenesis, nor increases cellular resistance to DNA-damaging agents. Nevertheless, the presence of the operator-constitutive mutation rescues mutagenesis in a recA background, indicating that imuABC are the only genes required at SOS-induced levels for translesion synthesis (TLS) in C. crescentus. Furthermore, these data also show that TLS mediated by ImuABC does not require RecA, unlike umuDC-dependent mutagenesis in E. coli. Copyright © 2017 Elsevier B.V. All rights reserved.

Genetic analysis of plant height in induced mutants of aromatic rice

International Nuclear Information System (INIS)

Kole, P.C.

2005-01-01

Inheritance of plant height in five gamma-ray induced mutants of aromatic rice cultivar Gobindabhog was studied through 6 x 6 diallel cross and segregation analyses. Diallel analysis revealed presence of additive and non-additive gene action with the preponderance of the latter. Proportion of dominant and recessive alleles was distributed unequally among the parents. The direction of dominance was towards tallness. The number of groups of genes was found to be three. The segregation analysis indicated the role of a single major recessive gene for height reduction in three mutants and, in another mutant, a single major recessive gene with negative modifiers. The other semi-dwarf mutant had two major recessive genes with almost equal effect in height reduction. The mutant allele(s) of the latter two mutants were non-allelic to sd sub(1) gene, which could be used as an alternative source of Dee Gee Woo Gen to widen the genetic diversity in semi-dwarfism [it

NKS/SOS-1 seminar on safety analysis

Energy Technology Data Exchange (ETDEWEB)

Lauridsen, K. [Risoe National Lab., Roskilde (Denmark); Anderson, K. [Karinta-Konsult (Sweden); Pulkkinen, U. [VTT Automation (Finland)

2001-05-01

The report describes presentations and discussions at a seminar held at Risoe on March 22-23, 2000. The title of the seminar was NKS/SOS-1 - Safety Analysis. It dealt with issues of relevance for the safety analysis for the entire nuclear safety field (notably reactors and nuclear waste repositories). Such issues were: objectives of safety analysis, risk criteria, decision analysis, expert judgement and risk communication. In addition, one talk dealt with criteria for chemical industries in Europe. The seminar clearly showed that the concept of risk is multidimensional, which makes clarity and transparency essential elements in risk communication, and that there are issues of common concern between different applications, such as how to deal with different kinds of uncertainty and expert judgement. (au)

NOAA NOS SOS, EXPERIMENTAL - Currents

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have currents data. *These services are for testing and evaluation use...

DNA degradation, UV sensitivity and SOS-mediated mutagenesis in strains of Escherichia coli deficient in single-strand DNA binding protein: Effects of mutations and treatments that alter levels of exonuclease V or RecA protein

International Nuclear Information System (INIS)

Lieberman, H.B.; Witkin, E.M.

1983-01-01

Certain strains suppress the temperature-sensitivity caused by ssb-1, which encodes a mutant ssDNA binding protein (SSB). At 42 0 C, such strains are extremely UV-sensitive, degrade their DNA extensively after UV irradiation, and are defficient in UV mutability and UV induction of recA protein synthesis. We transduced recC22, which eliminates Exonuclease V activity, and recAo281, which causes operator-constitutive synthesis of recA protein, into such an ssb-1 strain. Both double mutants degraded their DNA extensively at 42 0 C after UV irradiation, and both were even more UV-sensitive than the ssb-1 single mutant. We conclude that one or more nucleases other than Exonuclease V degrades DNA in the ssb recC strain, and that recA protein, even if synthesized copiously, can function efficiently in recombinational DNA repair and in control of post-UV DNA degradation only if normal SSB is also present. Pretreatment with nalidixic acid at 30 0 C restored normal UV mutability at 42 0 C, but did not increase UV resistance, in an ssb-1 strain. Another ssb allele, ssb-113, which blocks SOS induction at 30 0 C, increases spontaneous mutability more than tenfold. The ssb-113 allele was transduced into the SOS-constitutive recA730 strain SC30. This double mutant expressed the same elevated spontaneous and UV-induced mutability at 30 0 C as the ssb + recA730 strain, and was three times more UV-resistant than its ssb-113 recA + parent. We conclude that ssb-1 at 42 0 C and ssb-113 at 30 0 C block UV-induced activation of recA protease, but that neither allele interferes with subsequent steps in SOS-mediated mutagenesis. (orig.)

NOAA NOS SOS, EXPERIMENTAL - Wind

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have wind data. *These services are for testing and evaluation use only*...

Coronary artery ectasia in Noonan syndrome: Report of an individual with SOS1 mutation and literature review.

Science.gov (United States)

Calcagni, Giulio; Baban, Anwar; De Luca, Enrica; Leonardi, Benedetta; Pongiglione, Giacomo; Digilio, Maria Cristina

2016-03-01

Noonan syndrome (NS) is the second most frequent hereditary syndrome with cardiac involvement. Pulmonary valve stenosis and hypertrophic cardiomyopathy are the most prevalent cardiovascular abnormalities. We report on a 14-year-old girl with NS due to SOS1 mutation with pulmonary stenosis and idiopathic coronary ectasia. To the best of our knowledge, this is the first report describing coronary ectasia in a patient with NS secondary to a SOS1 mutation. We include a literature review of this rare association. © 2015 Wiley Periodicals, Inc.

Structural inhibition and reactivation of Escherichia coli septation by elements of the SOS and TER pathways

International Nuclear Information System (INIS)

Dopazo, A.; Tormo, A.; Aldea, M.; Vicente, M.

1987-01-01

The inhibition of cell division caused by induction of the SOS pathway in Escherichia coli structurally blocks septation, as deduced from two sets of results. Potential septation sites active at the time of SOS induction became inactivated, while those initiated during the following doubling time were active. Penicillin resistance increased in wild-type UV light-irradiated cells, a behavior similar to that observed in mutants in which structural blocks were introduced by inactivation of FtsA. Potential septation sites that have been structurally blocked by either the SOS division inhibitor, furazlocillin inhibition of PBP3, or inactivation of a TER pathway component, FtsA3, could be reactivated one doubling time after removal of the inhibitory agent in the presence of an active lon gene product. Reactivation of potential septation sites blocked by the presence of an inactivated FtsA3 was significantly lower when the lon protease was not active, suggesting that Lon plays a role in the removal of inactivated TER pathway products from the blocked potential septation sites

Lastekaitsepäeval avati Põltsamaal SOS-peremajad / Raivo Feldmann

Index Scriptorium Estoniae

Feldmann, Raivo

2010-01-01

Eesti teise SOS Lasteküla ametlikul avamisel Põltsamaal 1. juunil 2010. a. osalesid ka Norra suursaadik Eestis Stein Vegard Hagen ja SOS Lasteküla patroon proua Evelin Ilves. Presidendi abikaasa kinkis igale perele pereõunapuu ja koos kirjastusega Varrak igale peremajale väikese koduraamatukogu

The meaning of ordered SOS

NARCIS (Netherlands)

Mousavi, M.R.; Phillips, I.C.C.; Reniers, M.A.; Ulidowski, I.; Arun-Kumar, S.; Garg, N.

2006-01-01

Structured Operational Semantics (SOS) is a popular method for defining semantics by means of deduction rules. An important feature of deduction rules, or simply SOS rules, are negative premises, which are crucial in the definitions of such phenomena as priority mechanisms and time-outs. Orderings

Photochemistry in Power Plant and Urban Plumes over Forested and Agricultural Regions during SOS (1990s) and SENEX (2013) field intensives (Invited)

Science.gov (United States)

Trainer, M.; Frost, G. J.; Kim, S.; Ryerson, T. B.; Pollack, I. B.; Roberts, J. M.; Veres, P. R.; Flocke, F. M.; Neuman, J. A.; Nowak, J. B.; Nenes, A.; Warneke, C.; Graus, M.; Gilman, J.; Lerner, B. M.; Kuster, W.; Atlas, E. L.; Hanisco, T. F.; Wolfe, G. M.; Keutsch, F. N.; Kaiser, J.; Lee, Y.; Brock, C. A.; Middlebrook, A. M.; Liao, J.; Welti, A.; Parrish, D. D.; Fehsenfeld, F. C.; De Gouw, J. A.

2013-12-01

Extensive forested regions of the southeastern United States show high emissions of biogenic reactive hydrocarbons such as isoprene, while emissions of these compounds are typically much lower from agricultural areas. The Southern Oxidant Study (SOS) field intensives during the 1990s contributed to an improved understanding of ozone (O3) formation resulting from nitrogen oxides (NOx) emitted from urban areas and power plants in the presence and absence of the biogenic hydrocarbons. Decreases in NOx emissions from power plants and urban areas have contributed to the widespread reduction of ambient O3 over the southeastern US during the past two decades. Measurements of Volatile Organic Compounds (VOCs), NOx, and their reaction products made at successive distances downwind of emission sources during the SOS (1999) and the Southeast Nexus (SENEX, 2013) campaigns reflect the modulation of the photochemical processing of biogenic VOCs by ambient NOx concentrations. The results constrain the ambient levels of HOx radicals as a function of NOx, and they reflect the mechanisms of the coupling between anthropogenic and biogenic emissions that form species such as ozone, formaldehyde, PeroxyAcetic Nitric anhydride (PAN), nitric acid, as well as, inorganic and organic aerosols.

Induction and selection of mutants from in vitro cultured plant cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Yung Il; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-07-01

Mutant cell lines are useful for biochemical, physiological and genetical material for marker in various genetic manipulation experiments and for the direct use in crop plant improvement. Mutant selection may lead to the production of plants showing resistance or tolerance to specific environmental stress, such as solinity, drought, toxed metals, herbicides, pathogens and low temperature. In this review, these included the production of the somatic variation, the selection process itself and stability of the selected characters in cell culture and regenerated plant. Which would seem to be useful for improving plants and securring genetic resources. 45 refs. (Author).

Induction and selection of mutants from in vitro cultured plant cells

International Nuclear Information System (INIS)

Lee, Yung Il; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae

1994-07-01

Mutant cell lines are useful for biochemical, physiological and genetical material for marker in various genetic manipulation experiments and for the direct use in crop plant improvement. Mutant selection may lead to the production of plants showing resistance or tolerance to specific environmental stress, such as solinity, drought, toxed metals, herbicides, pathogens and low temperature. In this review, these included the production of the somatic variation, the selection process itself and stability of the selected characters in cell culture and regenerated plant. Which would seem to be useful for improving plants and securring genetic resources. 45 refs. (Author)

Primisulfuron herbicide-resistant tobacco plants: mutant selection in vitro by adventitious shoot formation from cultured leaf discs

International Nuclear Information System (INIS)

Harms, C.T.; DiMaio, J.J.; Jayne, S.M.; Middlesteadt, L.A.; Negrotto, D.V.; Thompson-Taylor, H.; Montoya, A.L.

1991-01-01

A simple procedure has been developed for the rapid and direct selection of herbicide-resistant mutant plants. The procedure uses adventitious shoot formation from suitable explants, such as leaf discs, on a shoot-inducing culture medium containing a toxic herbicide concentration. Resistant green shoots were thus isolated from tobacco (Nicotiana tabacum L.) leaf explants cultured on medium containing 100 μg 1−1 primisulfuron, a new sulfonylurea herbicide. Resistant shoots were recovered from both haploid and diploid explants after UV mutagenesis, as well as without mutagenic treatment. Three mutant plants of separate origin were further analyzed biochemically and genetically. Their acetohydroxyacid synthase (AHAS) enzyme activity was less inhibited by sulfonylurea herbicides than that of unselected, sensitive wild type plants. The extent of inhibition of the AHAS enzyme among the three mutants was different for different sulfonylurea and imidazolinone herbicides suggesting different sites were affected by each mutation. Herbicide tolerance was scored for germinating seedling populations and was found to be inherited as a single dominant nuclear gene. Adventitious shoot formation from cultured leaf discs was used to determine the cross tolerance of mutant plants to various herbicidal AHAS inhibitors. The usefulness of this rapid and direct scheme for mutant selection based on adventitious shoot formation or embryogenesis is discussed. (author)

NOAA NDBC SOS, 2006-present, sea_water_temperature

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have sea_water_temperature data. Because of the nature of SOS requests,...

SNAP Operating System (SOS) user's guide

International Nuclear Information System (INIS)

Sabuda, J.D.; Polito, J.; Walker, J.L.; Grant, F.H. III.

1982-03-01

The SNAP Operating System (SOS) is a FORTRAN 77 program which provides assistance to the safeguards analyst who uses the Safeguards Automated Facility Evaluation (SAFE) and the Safeguards Network Analysis Procedure (SNAP) techniques. Features offered by SOS are a data base system for storing a library of SNAP applications, computer graphics representation of SNAP models, a computer graphics editor to develop and modify SNAP models, a SAFE-to-SNAP interface, automatic generation of SNAP input data, and a computer graphics postprocessor for SNAP. The SOS User's Guide is designed to provide the user with the information necessary to use SOS effectively. Examples are used throughout to illustrate the concepts. The format of the user's guide follows the same sequence as would be used in executing an actual application

Homologous series of induced early mutants in indican rice. Pt.1. The production of homologous series of early mutants

International Nuclear Information System (INIS)

Chen Xiulan; Yang Hefeng; He Zhentian; Han Yuepeng; Liu Xueyu

1999-01-01

The percentage of homologous series of early mutants induced from the same Indican rice variety were almost the same (1.37%∼1.64%) in 1983∼1993, but the ones from the different eco-typical varieties were different. The early variety was 0.73%, the mid variety was 1.51%, and the late variety was 1.97%. The percentage of homologous series of early mutants from the varieties with the same pedigree and relationship were similar, but the one from the cog nation were lower than those from distant varieties. There are basic laws and characters in the homologous series of early mutants: 1. The inhibited phenotype is the basic of the homologous series of early mutants; 2. The production of the homologous series of early mutants is closely related with the growing period of the parent; 3. The parallel mutation of the stem and leaves are simultaneously happened with the variation of early or late maturing; 4. The occurrence of the homologous series of early mutants is in a state of imbalance. According to the law of parallel variability, the production of homologous series of early mutants can be predicted as long as the parents' classification of plant, pedigree and ecological type are identified. Therefore, the early breeding can be guided by the law of homologous series of early mutants

Use of the "gl1" Mutant and the "CA-rop2" Transgenic Plants of "Arabidopsis thaliana" in the Biology Laboratory Course

Science.gov (United States)

Zheng, Zhi-Liang

2006-01-01

This article describes the use of the "glabrous1 (g11)" mutant and constitutively active "(CA)-rop2" transgenic plants of "Arabidopsis thaliana" in teaching genetics laboratory for both high school and undergraduate students. The experiments provide students with F[subscript 1] and F[subscript 2] generations within a semester for genetic and…

One-way membrane trafficking of SOS in receptor-triggered Ras activation.

Science.gov (United States)

Christensen, Sune M; Tu, Hsiung-Lin; Jun, Jesse E; Alvarez, Steven; Triplet, Meredith G; Iwig, Jeffrey S; Yadav, Kamlesh K; Bar-Sagi, Dafna; Roose, Jeroen P; Groves, Jay T

2016-09-01

SOS is a key activator of the small GTPase Ras. In cells, SOS-Ras signaling is thought to be initiated predominantly by membrane recruitment of SOS via the adaptor Grb2 and balanced by rapidly reversible Grb2-SOS binding kinetics. However, SOS has multiple protein and lipid interactions that provide linkage to the membrane. In reconstituted-membrane experiments, these Grb2-independent interactions were sufficient to retain human SOS on the membrane for many minutes, during which a single SOS molecule could processively activate thousands of Ras molecules. These observations raised questions concerning how receptors maintain control of SOS in cells and how membrane-recruited SOS is ultimately released. We addressed these questions in quantitative assays of reconstituted SOS-deficient chicken B-cell signaling systems combined with single-molecule measurements in supported membranes. These studies revealed an essentially one-way trafficking process in which membrane-recruited SOS remains trapped on the membrane and continuously activates Ras until being actively removed via endocytosis.

The SH2 and SH3 domains of mammalian Grb2 couple the EGF receptor to the Ras activator mSos1.

Science.gov (United States)

Rozakis-Adcock, M; Fernley, R; Wade, J; Pawson, T; Bowtell, D

1993-05-06

Many tyrosine kinases, including the receptors for hormones such as epidermal growth factor (EGF), nerve growth factor and insulin, transmit intracellular signals through Ras proteins. Ligand binding to such receptors stimulates Ras guanine-nucleotide-exchange activity and increases the level of GTP-bound Ras, suggesting that these tyrosine kinases may activate a guanine-nucleotide releasing protein (GNRP). In Caenorhabditis elegans and Drosophila, genetic studies have shown that Ras activation by tyrosine kinases requires the protein Sem-5/drk, which contains a single Src-homology (SH) 2 domain and two flanking SH3 domains. Sem-5 is homologous to the mammalian protein Grb2, which binds the autophosphorylated EGF receptor and other phosphotyrosine-containing proteins such as Shc through its SH2 domain. Here we show that in rodent fibroblasts, the SH3 domains of Grb2 are bound to the proline-rich carboxy-terminal tail of mSos1, a protein homologous to Drosophila Sos. Sos is required for Ras signalling and contains a central domain related to known Ras-GNRPs. EGF stimulation induces binding of the Grb2-mSos1 complex to the autophosphorylated EGF receptor, and mSos1 phosphorylation. Grb2 therefore appears to link tyrosine kinases to a Ras-GNRP in mammalian cells.

The Arabidopsis mutant cev1 links cell wall signaling to jasmonate and ethylene responses.

Science.gov (United States)

Ellis, Christine; Karafyllidis, Ioannis; Wasternack, Claus; Turner, John G

2002-07-01

Biotic and abiotic stresses stimulate the synthesis of jasmonates and ethylene, which, in turn, induce the expression of genes involved in stress response and enhance defense responses. The cev1 mutant has constitutive expression of stress response genes and has enhanced resistance to fungal pathogens. Here, we show that cev1 plants have increased production of jasmonate and ethylene and that its phenotype is suppressed by mutations that interrupt jasmonate and ethylene signaling. Genetic mapping, complementation analysis, and sequence analysis revealed that CEV1 is the cellulose synthase CeSA3. CEV1 was expressed predominantly in root tissues, and cev1 roots contained less cellulose than wild-type roots. Significantly, the cev1 mutant phenotype could be reproduced by treating wild-type plants with cellulose biosynthesis inhibitors, and the cellulose synthase mutant rsw1 also had constitutive expression of VSP. We propose that the cell wall can signal stress responses in plants.

Plants Regeneration Derived From Various on Peanut on Mutant Lines

International Nuclear Information System (INIS)

Dewi, Kumala; Masrizal; Mugiono

1998-01-01

The study of calli, greenspot formation and shoot regeneration on peanut mutant lines has ben conducted by MS media. Three explants derived from shoot tips, embryo and seeding root of two mutant lines a/20/3 and D/25/3/2 were used in this experiment. the explants were cultured on modified MS media enriched by vitamins, growth regulation, amino acids for fourth teen calli were transferred on regeneration media. The ability of calli formation and plant regeneration of each explant and genotypes of plants was varied. Greenspot and shoot formation were observed seventh days after the calli transferred on regeneration media. It is shown that the ability of calli, greenspot and shoot formation of each explants and genotypes was varied. the high ability of calli, greenspot and shoot formation were found in explant derived from shoot tip and embryo. Seedling root explant has lower ability in calli formation, while greenspot and shoot was formatted. The ability of calli, greenspot and shoot formation on A/20/3 mutant line was better than D/25/3/2 mutant line. (author)

Induction of UV-resistant DNA replication in Escherichia coli: Induced stable DNA replication as an SOS function

International Nuclear Information System (INIS)

Kogoma, T.; Torrey, T.A.; Connaughton, M.J.

1979-01-01

The striking similarity between the treatments that induce SOS functions and those that result in stable DNA replication (continuous DNA replication in the absence of protein synthesis) prompted us to examine the possibility of stable DNA replication being a recA + lexA + -dependent SOS function. In addition to the treatments previously reported, ultraviolet (UV) irradiation or treatment with mitomycin C was also found to induce stable DNA replication. The thermal treatment of tif-1 strains did not result in detectable levels of stable DNA replication, but nalidixic acid readily induced the activity in these strains. The induction of stable DNA replication with nalidixic acid was severely suppressed in tif-1 lex A mutant strains. The inhibitory activity of lexA3 was negated by the presence of the spr-5l mutation, an intragenic suppressor of lexA3. Induced stable DNA replication was found to be considerably more resistant to UV irradiation than normal replication both in a uvr A6 strain and a uvr + strain. The UV-resistant replication occurred mostly in the semiconservative manner. The possible roles of stable DNA replication in repair of damaged DNA are discussed. (orig.)

Characterization of Foliage Mutants for Plant Variety Registration

International Nuclear Information System (INIS)

Affrida Abu Hassan; Shuhaimi Shamsuddin; Zaiton Ahmad

2011-01-01

Breeding for new plant varieties requires a substantial investment in terms of skill, labour, material resources and financing. Thus, registration of new plant variety is important to ensure return of revenue and protection of the breeder's right. Before a new variety is registered, it has to comply certain requirements under Plant Variety Protection Act. One of the most important requirements is, the new species/variety must be morphologically distinguishable from existing plant varieties. This paper discusses detailed leaf characteristics of 4 foliage mutants produced by Malaysian Nuclear Agency as part of the requirement for new variety registration. (author)

Structural landscape of the proline-rich domain of Sos1 nucleotide exchange factor.

Science.gov (United States)

McDonald, Caleb B; Bhat, Vikas; Kurouski, Dmitry; Mikles, David C; Deegan, Brian J; Seldeen, Kenneth L; Lednev, Igor K; Farooq, Amjad

2013-01-01

Despite its key role in mediating a plethora of cellular signaling cascades pertinent to health and disease, little is known about the structural landscape of the proline-rich (PR) domain of Sos1 guanine nucleotide exchange factor. Herein, using a battery of biophysical tools, we provide evidence that the PR domain of Sos1 is structurally disordered and adopts an extended random coil-like conformation in solution. Of particular interest is the observation that while chemical denaturation of PR domain results in the formation of a significant amount of polyproline II (PPII) helices, it has little or negligible effect on its overall size as measured by its hydrodynamic radius. Our data also show that the PR domain displays a highly dynamic conformational basin in agreement with the knowledge that the intrinsically unstructured proteins rapidly interconvert between an ensemble of conformations. Collectively, our study provides new insights into the conformational equilibrium of a key signaling molecule with important consequences on its physiological function. Copyright © 2013 Elsevier B.V. All rights reserved.

An orthosteric inhibitor of the RAS-SOS interaction.

Science.gov (United States)

Nickerson, Seth; Joy, Stephen T; Arora, Paramjit S; Bar-Sagi, Dafna

2013-01-01

Rat sarcoma (RAS) proteins are signaling nodes that transduce extracellular cues into precise alterations in cellular physiology by engaging effector pathways. RAS signaling thus regulates diverse cell processes including proliferation, migration, differentiation, and survival. Owing to this central role in governing mitogenic signals, RAS pathway components are often dysregulated in human diseases. Targeted therapy of RAS pathways has generally not been successful, largely because of the robust biochemistry of the targets and their multifaceted network of molecular regulators. The rate-limiting step of RAS activation is Son of Sevenless (SOS)-mediated nucleotide exchange involving a single evolutionarily conserved catalytic helix from SOS. Structure function data of this mechanism provided a strong platform to design an SOS-derived, helically constrained peptide mimic as an inhibitor of the RAS-SOS interaction. In this chapter, we review RAS-SOS signaling dynamics and present evidence supporting the novel paradigm of inhibiting their interaction as a therapeutic strategy. We then describe a method of generating helically constrained peptide mimics of protein surfaces, which we have employed to inhibit the RAS-SOS active site interaction. The biochemical and functional properties of this SOS mimic support the premise that inhibition of RAS-nucleotide exchange can effectively block RAS activation and downstream signaling. © 2013 Elsevier Inc. All rights reserved.

SOS1 gene polymorphisms are associated with gestational diabetes mellitus in a Chinese population: Results from a nested case-control study in Taiyuan, China.

Science.gov (United States)

Chen, Qiong; Yang, Hailan; Feng, Yongliang; Zhang, Ping; Wu, Weiwei; Li, Shuzhen; Thompson, Brian; Wang, Xin; Peng, Tingting; Wang, Fang; Xie, Bingjie; Guo, Pengge; Li, Mei; Wang, Ying; Zhao, Nan; Wang, Suping; Zhang, Yawei

2018-03-01

Gestational diabetes mellitus is a growing public health concern due to its large disease burden; however, the underlying pathophysiology remains unclear. Therefore, we examined the relationship between 107 single-nucleotide polymorphisms in insulin signalling pathway genes and gestational diabetes mellitus risk using a nested case-control study. The SOS1 rs7598922 GA and AA genotype were statistically significantly associated with reduced gestational diabetes mellitus risk ( p trend  = 0.0006) compared with GG genotype. At the gene level, SOS1 was statistically significantly associated with gestational diabetes mellitus risk after adjusting for multiple comparisons. Moreover, AGGA and GGGG haplotypes in SOS1 gene were associated with reduced risk of gestational diabetes mellitus. Our study provides evidence for an association between the SOS1 gene and risk of gestational diabetes mellitus; however, its role in the pathogenesis of gestational diabetes mellitus will need to be verified by further studies.

Prototyping SOS meta-theory in Maude

NARCIS (Netherlands)

Mousavi, M.R.; Reniers, M.A.; Mosses, P.D.; Ulidowski, I.

2006-01-01

We present a prototype implementation of SOS meta-theory in the Maude term rewriting language. The prototype defines the basic concepts of SOS meta-theory (e.g., transition formulae, deduction rules and transition system specifications) in Maude. Besides the basic definitions, we implement methods

Semantics and expressiveness of ordered SOS

NARCIS (Netherlands)

Mousavi, M.R.; Phillips, I.C.C.; Reniers, M.A.; Ulidowski, I.

2009-01-01

Structured Operational Semantics (SOS) is a popular method for defining semantics by means of transition rules. An important feature of SOS rules is negative premises, which are crucial in the definitions of such phenomena as priority mechanisms and time-outs. However, the inclusion of negative

Collection for SOS animaux

CERN Multimedia

2005-01-01

The Pays de Gex animal shelter is collecting funds. There will be things to buy. You will be able to make a donation and/or become a member of the association or simply get information. SOS Animaux stall (Hall, Build. 60, next to restaurant 1) On Wednesday 23 November 2005 (from 9h - 17h non-stop)

Forward and reverse genetics: The LORE1 retrotransposon insertion mutants

DEFF Research Database (Denmark)

Fukai, Eigo; Malolepszy, Anna; Sandal, Niels Nørgaard

2014-01-01

The endogenous Lotus retrotransposon 1 (LORE1) transposes in the germ line of Lotus japonicus plants that carry an active element. This feature of LORE1 has been exploited for generation of a large non-transgenic insertion mutant population, where insertions have been annotated using next-generat...

Drastic anthocyanin increase in response to PAP1 overexpression in fls1 knockout mutant confers enhanced osmotic stress tolerance in Arabidopsis thaliana.

Science.gov (United States)

Lee, Won Je; Jeong, Chan Young; Kwon, Jaeyoung; Van Kien, Vu; Lee, Dongho; Hong, Suk-Whan; Lee, Hojoung

2016-11-01

KEY MESSAGE : pap1 - D/fls1ko double mutant plants that produce substantial amounts of anthocyanin show tolerance to abiotic stress. Anthocyanins are flavonoids that are abundant in various plants and have beneficial effects on both plants and humans. Many genes in flavonoid biosynthetic pathways have been identified, including those in the MYB-bHLH-WD40 (MBW) complex. The MYB gene Production of Anthocyanin Pigment 1 (PAP1) plays a particularly important role in anthocyanin accumulation. PAP1 expression in many plant systems strongly increases anthocyanin levels, resulting in a dark purple color in many plant organs. In this study, we generated double mutant plants that harbor fls1ko in the pap1-D background (i.e., pap1-D/fls1ko plants), to examine whether anthocyanins can be further enhanced by blocking flavonol biosynthesis under PAP1 overexpression. We also wanted to examine whether the increased anthocyanin levels contribute to defense against osmotic stresses. The pap1-D/fls1ko mutants accumulated higher anthocyanin levels than pap1-D plants in both control and sucrose-treated conditions. However, flavonoid biosynthesis genes were slightly down-regulated in the pap1-D/fls1ko seedlings as compared to their expression in pap1-D seedlings. We also report the performance of pap1-D/fls1ko seedlings in response to plant osmotic stresses.

Inducible error-prone repair in B. subtilis. Progress report, September 1, 1978-August 31, 1979

International Nuclear Information System (INIS)

Yasbin, R.E.

1979-01-01

The mechanism of activation and the mode of action of the SOS system in the bacterium Bacillus subtilis is under study. Interesting aspects of the SOS system in B. subtilis are: (1) the differences between SOS functions in this bacterium and in the enteric bacteria; (2) the spontaneous activation of SOS functions in component cells; and (3) the difficulty in obtaining consistent results for mutation studies in this bacterium. In order to characterize the SOS system of B. subtilis, it was proposed to: (1) isolate bacteria mutated in genes controlling various repair function; (2) investigate inducible repair; (3) determine the role of endogeneous Bacillus prophages in SOS functions; and (4) develop a tester system for potential carcinogens from competent Bacillus subtilis cells. Research has been able to: (1) isolate strains of B. subtilis in which the endogeneous prophages have been removed or neutralized; (2) demonstrate the association of one SOS function with prophage SPB; (3) demonstrate that the survival of uv-irradiated B. subtilis is not significantly altered by the removal and neutralization of the endogeneous prophages; (4) develop competant B. subtilis into a tester system; and (5) show that DNA polymerase III is absolutely necessary for W reactivation. In addition, uv and mitomycin C resistant mutants have been isolated and inducible postreplication repair in excision-repair deficient mutants of B. subtilis has been studied. The last two results are somewaht confusing but highly exciting in regards to DNA repair mechanisms in B. subtilis

NOAA NDBC SOS, 2007-present, sea_water_practical_salinity

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have sea_water_practical_salinity data. Because of the nature of SOS...

Structural analyses of polymorphic transitions of sn-1, 3-distearoyl-2-oleoylglycerol (SOS) and sn-1, 3-dioleoyl-2-stearoylglycerol (OSO): assessment on steric hindrance of unsaturated and saturated acyl chain interactions.

Science.gov (United States)

Yano, J; Sato, K; Kaneko, F; Small, D M; Kodali, D R

1999-01-01

Polymorphic transformations in two saturated-unsaturated mixed acid triacylglycerols, SOS (sn -1,3-distearoyl-2-oleoylglycerol) and OSO (sn -1,3-dioleoyl-2-stearoylglycerol), have been studied by FT-IR spectroscopy using deuterated specimens in which stearoyl chains are fully deuterated. A reversible phase transition between sub alpha and alpha and a series of irreversible transitions (alpha-->gamma-->beta'-->beta (beta2, beta1) for SOS and alpha-->beta'-->beta for OSO) were studied with an emphasis on the conformational ordering process of stearoyl and oleoyl chains. The alpha-->sub alpha reversible transition was due to the orientational change of stearoyl chains in the lateral directions from the hexagonal subcell to a perpendicularly packed one. As the first stage of the series of irreversible transitions from alpha to beta, the conformational ordering of saturated chains took place in the alpha-->gamma transition of SOS and in the alpha-->beta' transition of OSO; one stearoyl chain in SOS and OSO takes the all-trans conformation and the second stearoyl chain in SOS takes the bent conformation like those observed in the most stable beta-type. As the final stage, the ordering of unsaturated chains occurred in the beta'-->beta transition both for SOS and OSO. A conversion in the layered structure from bilayer to trilayer was also accompanied by the conformational ordering in the alpha-->gamma transition of SOS and in the beta'-->beta transition of OSO.

Nominal SOS

NARCIS (Netherlands)

Cimini, M.; Mousavi, M.R.; Reniers, M.A.; Gabbay, M.J.

2012-01-01

Plotkin's style of Structural Operational Semantics (SOS) has become a de facto standard in giving operational semantics to formalisms and process calculi. In many such formalisms and calculi, the concepts of names, variables and binders are essential ingredients. In this paper, we propose a formal

NOAA NOS SOS, EXPERIMENTAL, 1902-present, Salinity

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have salinity data. *These services are for testing and evaluation use...

NOAA NOS SOS, EXPERIMENTAL, 1902-present, Conductivity

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have conductivity data. *These services are for testing and evaluation use...

Gamma ray induced mutants in Coleus

Energy Technology Data Exchange (ETDEWEB)

Vasudevan, K; Jos, J S [Central Tuber Crops Research Institute, Trivandrum, Kerala (India)

1988-07-01

The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M{sub 1}V{sub 1} generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m{sup 2} area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing.

Gamma ray induced mutants in Coleus

International Nuclear Information System (INIS)

Vasudevan, K.; Jos, J.S.

1988-01-01

The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M 1 V 1 generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m 2 area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing

Root hair mutants of barley

International Nuclear Information System (INIS)

Engvild, K.C.; Rasmussen, K.

2005-01-01

Barley mutants without root hairs or with short or reduced root hairs were isolated among M 2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M 2 seeds were sown in the field the same day. Spikes, 4-6 per M 1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants

Science.gov (United States)

Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

2016-01-01

The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na+/H+) antiporter that transports Na+ into the vacuole and exports H+ into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na+/H+ antiporter that exports Na+ to the extracellular space and imports H+ into the plant cell. Plants rely on these enzymes either to keep Na+ out of the cell or to sequester Na+ into vacuoles to avoid the toxic level of Na+ in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. PMID:26985021

A method for the production and expedient screening of CRISPR/Cas9-mediated non-transgenic mutant plants.

Science.gov (United States)

Chen, Longzheng; Li, Wei; Katin-Grazzini, Lorenzo; Ding, Jing; Gu, Xianbin; Li, Yanjun; Gu, Tingting; Wang, Ren; Lin, Xinchun; Deng, Ziniu; McAvoy, Richard J; Gmitter, Frederick G; Deng, Zhanao; Zhao, Yunde; Li, Yi

2018-01-01

Developing CRISPR/Cas9-mediated non-transgenic mutants in asexually propagated perennial crop plants is challenging but highly desirable. Here, we report a highly useful method using an Agrobacterium -mediated transient CRISPR/Cas9 gene expression system to create non-transgenic mutant plants without the need for sexual segregation. We have also developed a rapid, cost-effective, and high-throughput mutant screening protocol based on Illumina sequencing followed by high-resolution melting (HRM) analysis. Using tetraploid tobacco as a model species and the phytoene desaturase ( PDS ) gene as a target, we successfully created and expediently identified mutant plants, which were verified as tetra-allelic mutants. We produced pds mutant shoots at a rate of 47.5% from tobacco leaf explants, without the use of antibiotic selection. Among these pds plants, 17.2% were confirmed to be non-transgenic, for an overall non-transgenic mutation rate of 8.2%. Our method is reliable and effective in creating non-transgenic mutant plants without the need to segregate out transgenes through sexual reproduction. This method should be applicable to many economically important, heterozygous, perennial crop species that are more difficult to regenerate.

Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants.

Science.gov (United States)

Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

2016-05-01

The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na(+)/H(+)) antiporter that transports Na(+) into the vacuole and exports H(+) into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na(+)/H(+) antiporter that exports Na(+) to the extracellular space and imports H(+) into the plant cell. Plants rely on these enzymes either to keep Na(+) out of the cell or to sequester Na(+) into vacuoles to avoid the toxic level of Na(+) in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

Micro-Tom Tomato as an Alternative Plant Model System: Mutant Collection and Efficient Transformation.

Science.gov (United States)

Shikata, Masahito; Ezura, Hiroshi

2016-01-01

Tomato is a model plant for fruit development, a unique feature that classical model plants such as Arabidopsis and rice do not have. The tomato genome was sequenced in 2012 and tomato is becoming very popular as an alternative system for plant research. Among many varieties of tomato, Micro-Tom has been recognized as a model cultivar for tomato research because it shares some key advantages with Arabidopsis including its small size, short life cycle, and capacity to grow under fluorescent lights at a high density. Mutants and transgenic plants are essential materials for functional genomics research, and therefore, the availability of mutant resources and methods for genetic transformation are key tools to facilitate tomato research. Here, we introduce the Micro-Tom mutant database "TOMATOMA" and an efficient transformation protocol for Micro-Tom.

Genetic separation of Escherichia coli recA functions for SOS mutagenesis and repressor cleavage

International Nuclear Information System (INIS)

Ennis, D.G.; Ossanna, N.; Mount, D.W.

1989-01-01

Evidence is presented that recA functions which promote the SOS functions of mutagenesis, LexA protein proteolysis, and lambda cI repressor proteolysis are each genetically separable from the others. This separation was observed in recombination-proficient recA mutants and rec+ (F' recA56) heterodiploids. recA430, recA433, and recA435 mutants and recA+ (F' recA56) heterodiploids were inducible for only one or two of the three functions and defective for mutagenesis. recA80 and recA432 mutants were constitutively activated for two of the three functions in that these mutants did not have to be induced to express the functions. We propose that binding of RecA protein to damaged DNA and subsequent interaction with small inducer molecules gives rise to conformational changes in RecA protein. These changes promote surface-surface interactions with other target proteins, such as cI and LexA proteins. By this model, the recA mutants are likely to have incorrect amino acids substituted as sites in the RecA protein structure which affect surface regions required for protein-protein interactions. The constitutively activated mutants could likewise insert altered amino acids at sites in RecA which are involved in the activation of RecA protein by binding small molecules or polynucleotides which metabolically regulate RecA protein

Comparative study of SOS response induced by hydrogen peroxide in the absence or presence of iron ions, in Escherichia coli; Estudo comparativo da resposta SOS induzida pelo peroxido de hidrogenio em presenca e ausencia de ions ferro, em Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Almeida, Carlos Eduardo Bonacossa de

1994-07-01

The H{sub 2}O{sub 2} is an reactive oxygen specie that arises from cell respiration process. It may cause deleterious effects on cell, by reacting with transition metals like iron. In this way it yields free radicals that are able to damage organic molecules, mainly DNA. Recent works have suggested that in the absence of Fe ions H{sub 2}O{sub 2} still damages Escherichia coli DNA. This work presents a comparative analysis of cell SOS responses to DNA damage in Escherichia coli and Salmonella typhimurium mutants pretreated or not with a Fe{sup 2+} ion chelator (dipyridyl) and then treated with H{sub 2}O{sub 2}. The systems analysed were the lysogenic induction, Weigle reactivation, mutagenesis and cell inactivation curves. The cell inactivation curves were themselves distinct, in relation to both treatments. The increased sensitivity found in the lexA1 and recA13 mutants, when treated with dipyridyl and H{sub 2}O{sub 2}, suggests an important role of SOS response in repairing the lesions caused by this treatment. The profiles of the lysogenic induction and mutagenesis curves were also distinct in both treatments. The results of Weigle reactivation suggest that the products of uvrA and lexA genes have an important role in UV-damaged bacteriophage DNA repair, when dipyridyl-pretreated cells are treated with H{sub 2}O{sub 2}. All the results suggest that Fe-independent lesions produced by H{sub 2}O{sub 2} are different from the ones produced in the presence of this ion. (author)

Inhibition of the SOS response of Escherichia coli by the Ada protein

International Nuclear Information System (INIS)

Vericat, J.A.; Guerrero, R.; Barbe, J.

1988-01-01

Induction of the adaptive response by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) caused a decrease in the UV-mediated expression of both recA and sfiA genes but not of the umuDC gene. On the other hand, the adaptive response did not affect the temperature-promoted induction of SOS response in a RecA441 mutant. The inhibitory effect on the UV-triggered expression of the recA and sfiA genes was not dependent on either the alkA gene or the basal level of RecA protein, but rather required the ada gene. Furthermore, an increase in the level of the Ada protein, caused by the runaway plasmid pYN3059 in which the ada gene is regulated by the lac promoter, inhibited UV-mediated recA gene expression even in cells to which the MNNG-adaptive treatment had not been applied. This inhibitory effect of the adaptive pretreatment was not observed either in RecBC- strains or in RecBC mutants lacking exonuclease V-related nuclease activity. However, RecF- mutants showed an adaptive response-mediated decrease in UV-promoted induction of the recA gene

Bacterial SOS response: a food safety perspective

NARCIS (Netherlands)

Veen, van der S.; Abee, T.

2011-01-01

The SOS response is a conserved inducible pathway in bacteria that is involved in DNA repair and restart of stalled replication forks. Activation of the SOS response can result in stress resistance and mutagenesis. In food processing facilities and during food preservation, bacteria are exposed to

SOS-projektet

DEFF Research Database (Denmark)

Blomhøj, Morten; Jensen, Tomas Højgaard

2007-01-01

Artiklen beretter om og analyserer det såkaldte SOS-projekt, hvor matematiklærere fra grundskolen, gymnasiet og læreruddannelsen har samarbejdet med matematikdidaktiske forskere om at undersøge og afhjælpe nogle af de udfordringer som danske elever møder i matematik ved overgangen fra grundskole...

Mighty Dwarfs: Arabidopsis autoimmune mutants and their usages in genetic dissection of plant immunity

Directory of Open Access Journals (Sweden)

Rowan Wersch

2016-11-01

Full Text Available Plants lack the adaptive immune system possessed by mammals. Instead they rely on innate immunity to defend against pathogen attacks. Genomes of higher plants encode a large number of plant immune receptors belonging to different protein families, which are involved in the detection of pathogens and activation of downstream defense pathways. Plant immunity is tightly controlled to avoid activation of defense responses in the absence of pathogens, as failure to do so can lead to autoimmunity that compromises plant growth and development. Many autoimmune mutants have been reported, most of which are associated with dwarfism and often spontaneous cell death. In this review, we summarize previously reported Arabidopsis autoimmune mutants, categorizing them based on their functional groups. We also discuss how their obvious morphological phenotypes make them ideal tools for epistatic analysis and suppressor screens, and summarize genetic screens that have been carried out in various autoimmune mutant backgrounds.

Comparative study of SOS response induced by hydrogen peroxide in the absence or presence of iron ions, in Escherichia coli

International Nuclear Information System (INIS)

Almeida, Carlos Eduardo Bonacossa de

1994-01-01

The H 2 O 2 is an reactive oxygen specie that arises from cell respiration process. It may cause deleterious effects on cell, by reacting with transition metals like iron. In this way it yields free radicals that are able to damage organic molecules, mainly DNA. Recent works have suggested that in the absence of Fe ions H 2 O 2 still damages Escherichia coli DNA. This work presents a comparative analysis of cell SOS responses to DNA damage in Escherichia coli and Salmonella typhimurium mutants pretreated or not with a Fe 2+ ion chelator (dipyridyl) and then treated with H 2 O 2 . The systems analysed were the lysogenic induction, Weigle reactivation, mutagenesis and cell inactivation curves. The cell inactivation curves were themselves distinct, in relation to both treatments. The increased sensitivity found in the lexA1 and recA13 mutants, when treated with dipyridyl and H 2 O 2 , suggests an important role of SOS response in repairing the lesions caused by this treatment. The profiles of the lysogenic induction and mutagenesis curves were also distinct in both treatments. The results of Weigle reactivation suggest that the products of uvrA and lexA genes have an important role in UV-damaged bacteriophage DNA repair, when dipyridyl-pretreated cells are treated with H 2 O 2 . All the results suggest that Fe-independent lesions produced by H 2 O 2 are different from the ones produced in the presence of this ion. (author)

Genetic characterization of the inducible SOS-like system of Bacillus subtilis

Energy Technology Data Exchange (ETDEWEB)

Love, P.E.; Yasbin, R.E.

1984-12-01

The SOS-like system of Bacillus subtilis consists of several coordinately induced phenomena which are expressed after cellular insult such as DNA damage of inhibition of DNA replication. Mutagenesis of the bacterial chromosomes and the development of maintenance of competence also appear to be involved in the SOS-like response in this bacterium. The genetic characterization of the SOS-like system has involved an analysis of (i) the effects of various DNA repair mutations on the expression of inducible phenomena and (ii) the tsi-23 mutation, which renders host strains thermally inducible for each of the SOS-like functions. Bacterial filamentation was unaffected by any of the DNA repair mutations studied. In contrast, the induction of prophage after thermal or UV pretreatment was abolished in strains carrying the recE4, recA1, recB2, or recG13 mutation. The Weigle reactivation of UV-damaged bacteriophage was also inhibited by the recE4, recA1, recB2, or recG13 mutation, whereas levels of Weigle reactivation were lower in strains which carried the uvrA42, polA5, or rec-961 mutation than in the DNA repair-proficient strain. Strains which carried the recE4 mutation were incapable of chromosomal DNA-mediated transformation, and the frequency of this event was decreased in strains carrying recA1, recB2, or tsi-23 mutation. Plasmid DNA transformation efficiency was decreased only in strains carrying the tsi-23 mutation in addition to the recE4, recA1, or recB2 mutation. The results indicate that the SOS-like system of B. subtilis is regulated at different levels by two or more gene products. In this report, the current data regarding the genetic regulation of inducible phenomena are summarized, and a model is proposed to explain the mechanism of SOS-like induction in B. subtillis. 50 references, 3 figures, 6 tables.

Isolation of uvh1, an Arabidopsis mutant hypersensitive to ultraviolet light and ionizing radiation

International Nuclear Information System (INIS)

Harlow, G.R.; Jenkins, M.E.; Pittalwala, T.S.; Mount, D.W.

1994-01-01

A genetic screen for mutants of Arabidopsis that are hypersensitive to UV light was developed and used to isolate a new mutant designated uvh1. UV hypersensitivity in uvh1 was due to a single recessive trait that is probably located on chromosome 3. Although isolated as hypersensitive to an acute exposure to UV-C light, uvh1 was also hypersensitive to UV-B wavelengths, which are present in sunlight that reaches the earth's surface. UV-B damage to both wild-type and uvh1 plants could be significantly reduced by subsequent exposure of UV-irradiated plants to photoreactivating light, showing that photoreactivation of UV-B damage is important for plant viability and that uvh1 plants are not defective in photoreactivation. A new assay for DNA damage, the Dral assay, was developed and used to show that exposure of wild-type and uvh1 plants to a given dose of UV light induces the same amount of damage in chloroplast and nuclear DNA. Thus, uvh1 is not defective in a UV protective mechanism. uvh1 plants were also found to be hypersensitive to ionizing radiation. These results suggest that uvh1 is defective in a repair or tolerance mechanism that normally provides plants with resistance to several types of DNA damage

Isolation of uvh1, an Arabidopsis mutant hypersensitive to ultraviolet light and ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Harlow, G. R.; Jenkins, M. E.; Pittalwala, T. S.; Mount, D. W.

1994-02-15

A genetic screen for mutants of Arabidopsis that are hypersensitive to UV light was developed and used to isolate a new mutant designated uvh1. UV hypersensitivity in uvh1 was due to a single recessive trait that is probably located on chromosome 3. Although isolated as hypersensitive to an acute exposure to UV-C light, uvh1 was also hypersensitive to UV-B wavelengths, which are present in sunlight that reaches the earth's surface. UV-B damage to both wild-type and uvh1 plants could be significantly reduced by subsequent exposure of UV-irradiated plants to photoreactivating light, showing that photoreactivation of UV-B damage is important for plant viability and that uvh1 plants are not defective in photoreactivation. A new assay for DNA damage, the Dral assay, was developed and used to show that exposure of wild-type and uvh1 plants to a given dose of UV light induces the same amount of damage in chloroplast and nuclear DNA. Thus, uvh1 is not defective in a UV protective mechanism. uvh1 plants were also found to be hypersensitive to ionizing radiation. These results suggest that uvh1 is defective in a repair or tolerance mechanism that normally provides plants with resistance to several types of DNA damage.

Behavior of radionuclides and related elements in plants. Screening and characterization of cesium requirement mutants from mutagenized arabidopsis thaliana

Energy Technology Data Exchange (ETDEWEB)

Yamagami, Mutsumi; Yanai, Masumi; Hisamatsu, Shunichi; Inaba, Jiro [Inst. for Environmental Sciences, Rokkasho, Aomori (Japan)

2002-07-01

We have investigated the effect of climate on the metabolic behavior of various elements in a specific plant. The following items have been examined: the effect of climate conditions including Yamase (prevailing windows from the Pacific Ocean side area of Aomori Prefecture) on the elemental transfer factor of rice, the effect of light conditions on metabolism of elements in a plant, the effect of environmental factors on elemental movements at a cell level, and establishment of a mutant plant strain to obtain elemental requirement. This paper describes the development of a method for screening and characterizing cesium resistance mutants from Arabidopsis thaliana. Arabidopsis is a small herbaceous plant which is used for experimental molecular botany. To isolate mutant in cesium uptake or accumulation, we have devised a screening method using energy-dispersive x-ray microanalysis (EDX) of mutagenized Arabidopsis leaves. The seeds for the selection were M{sub 2} seeds derived from ethyl methane sulfonate (EMS)-treated plants. A double screening method was used to isolate about 50 Cs-resistant mutants. In the first screening experiment, EMS-mutagenized seeds were grown in medium containing 3 mM Cs. The wild type Arabidopsis usually died, but Cs-resistant mutants survived. These were transferred into soil for harvest of first-screening-seeds. In the successive experiment, first-screening-seeds were grown in medium containing 1 mM Cs, and Cs of the leaves was analyzed by EDX. We identified about 50 mutants in Cs uptake or accumulation after screening over 100,000 seedlings. These mutants showed either excessive accumulation of Cs in leaves or an inability to accumulate Cs at a normal concentration. The uptake rates of Cs in those mutants were also examined by using {sup 134}Cs radioactive tracer. (author)

Dwarf mutant of rice variety Seratus Malam

International Nuclear Information System (INIS)

Mugiono, P. S.; Soemanggono, A.M.R.

1989-01-01

Full text: Seeds of 'Seratus Malam', a local tall upland variety with long panicles and high yield potential were irradiated with 10-50 krad gamma rays in 1983. From 50,000 M 2 plants, 130 semidwarf mutants and 1 dwarf mutant were selected. The dwarf mutant M-362 was obtained from the 10 krad treatment. The mutant shows about 50% reduction in plant height, but also in number of productive tillers. Thus the yield per plant is also significantly less. However, the mutant gene is not allelic to DGWG and therefore may be useful in cross breeding. (author)

CMOS/SOS processing

Science.gov (United States)

Ramondetta, P.

1980-01-01

Report describes processes used in making complementary - metal - oxide - semiconductor/silicon-on-sapphire (CMOS/SOS) integrated circuits. Report lists processing steps ranging from initial preparation of sapphire wafers to final mapping of "good" and "bad" circuits on a wafer.

SOS2 and ACP1 Loci Identified through Large-Scale Exome Chip Analysis Regulate Kidney Development and Function

DEFF Research Database (Denmark)

Li, Man; Li, Yong; Weeks, Olivia

2017-01-01

Genome-wide association studies have identified >50 common variants associated with kidney function, but these variants do not fully explain the variation in eGFR. We performed a two-stage meta-analysis of associations between genotypes from the Illumina exome array and eGFR on the basis of serum...... creatinine (eGFRcrea) among participants of European ancestry from the CKDGen Consortium (nStage1: 111,666; nStage2: 48,343). In single-variant analyses, we identified single nucleotide polymorphisms at seven new loci associated with eGFRcrea (PPM1J, EDEM3, ACP1, SPEG, EYA4, CYP1A1, and ATXN2L; PStage1......associations of functional rare variants in three genes with eGFRcrea, including a novel association with the SOS Ras/Rho guanine nucleotide exchange factor 2 gene, SOS2 (P=5.4×10(-8) by sequence kernel...

Hydrothermal Carbonization of Spent Osmotic Solution (SOS Generated from Osmotic Dehydration of Blueberries

Directory of Open Access Journals (Sweden)

Kaushlendra Singh

2014-09-01

Full Text Available Hydrothermal carbonization of spent osmotic solution (SOS, a waste generated from osmotic dehydration of fruits, has the potential of transformation into hydrochars, a value-added product, while reducing cost and overall greenhouse gas emissions associated with waste disposal. Osmotic solution (OS and spent osmotic solution (SOS generated from the osmotic dehydration of blueberries were compared for their thermo-chemical decomposition behavior and hydrothermal carbonization. OS and SOS samples were characterized for total solids, elemental composition, and thermo-gravimetric analysis (TGA. In addition, hydrothermal carbonization was performed at 250 °C and for 30 min to produce hydrochars. The hydrochars were characterized for elemental composition, Brunauer-Emmett-Teller (BET surface area, particle shape and surface morphology. TGA results show that the SOS sample loses more weight in the lower temperature range than the OS sample. Both samples produced, approximately, 40%–42% (wet-feed basis hydrochar during hydrothermal carbonization but with different properties. The OS sample produced hydrochar, which had spherical particles of 1.79 ± 1.30 μm diameter with a very smooth surface. In contrast, the SOS sample produced hydrochar with no definite particle shape but with a raspberry-like surface.

NOAA NOS SOS, EXPERIMENTAL, 1853-present, Barometric Pressure

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have barometric pressure data. *These services are for testing and...

Allosteric Mutant IDH1 Inhibitors Reveal Mechanisms for IDH1 Mutant and Isoform Selectivity

Energy Technology Data Exchange (ETDEWEB)

Xie, Xiaoling; Baird, Daniel; Bowen, Kimberly; Capka, Vladimir; Chen, Jinyun; Chenail, Gregg; Cho, YoungShin; Dooley, Julia; Farsidjani, Ali; Fortin, Pascal; Kohls, Darcy; Kulathila, Raviraj; Lin, Fallon; McKay, Daniel; Rodrigues, Lindsey; Sage, David; Touré, B. Barry; van der Plas, Simon; Wright, Kirk; Xu, Ming; Yin, Hong; Levell, Julian; Pagliarini, Raymond A. (Novartis)

2017-03-01

Oncogenic IDH1 and IDH2 mutations contribute to cancer via production of R-2-hydroxyglutarate (2-HG). Here, we characterize two structurally distinct mutant- and isoform-selective IDH1 inhibitors that inhibit 2-HG production. Both bind to an allosteric pocket on IDH1, yet shape it differently, highlighting the plasticity of this site. Oncogenic IDH1R132H mutation destabilizes an IDH1 “regulatory segment,” which otherwise restricts compound access to the allosteric pocket. Regulatory segment destabilization in wild-type IDH1 promotes inhibitor binding, suggesting that destabilization is critical for mutant selectivity. We also report crystal structures of oncogenic IDH2 mutant isoforms, highlighting the fact that the analogous segment of IDH2 is not similarly destabilized. This intrinsic stability of IDH2 may contribute to observed inhibitor IDH1 isoform selectivity. Moreover, discrete residues in the IDH1 allosteric pocket that differ from IDH2 may also guide IDH1 isoform selectivity. These data provide a deeper understanding of how IDH1 inhibitors achieve mutant and isoform selectivity.

Flowering responses to light-breaks in photomorphogenic mutants of Arabidopsis thaliana, a long-day plant

International Nuclear Information System (INIS)

Goto, N.; Kumagai, T.; Koornneef, M.

1991-01-01

Flowering response and plant form of photomorphogenic mutants (hy1, hy2, hy3, hy4 and hy5) of Arabidopsis thaliana (L.), a long-day plant, were examined in long and short days. There were only slight differences among genotypes including Landsberg wild type with respect to the flowering time under long days. The effect of 1 h light-(night)-breaks of far-red, red, blue and white light given in the middle of the dark period of plants grown under short days, was studied. Effects of far-red light applied at the end or the beginning of the main photoperiod on flowering and plant form were also examined. The light-breaks with all the above mentioned light qualities promoted floral initiation of all the genotypes including the wild type in terms of both the flowering time and the number of rosette leaves. In general, far-red light was most effective. It is possible to classify the hy-mutants into 3 groups by their responses to light-breaks under short day conditions: (a) Mutants hy2 and hy3, which have a reduced number of rosette leaves, and flower early. Red light is as effective as far-red light. The wavelength of light-breaks is relatively unimportant for flowering response. (b) Mutants hy4, hy5 and Landsberg wild type, which have a greater number of rosette leaves, and flower relatively late. The effectiveness of light-breaks is in the following order, far-red, blue, and red light, which is in reverse order to the transformation of phytochrome to the P fr form. (c) Mutant hy1, which behaves anomalously with respect to relations between flowering time and number of rosette leaves; late flowering with reduced number of rosette leaves. Red, blue and far-red light are effective, but white light is ineffective for reducing the number of rosette leaves. When far-red light was given in the middle of the night or at the end of the main photoperiod, it markedly reduced the number of rosette leaves compared to those grown under short days for all the genotypes, while when

SOS, the formidable strategy of bacteria against aggressions.

Science.gov (United States)

Baharoglu, Zeynep; Mazel, Didier

2014-11-01

The presence of an abnormal amount of single-stranded DNA in the bacterial cell constitutes a genotoxic alarm signal that induces the SOS response, a broad regulatory network found in most bacterial species to address DNA damage. The aim of this review was to point out that beyond being a repair process, SOS induction leads to a very strong but transient response to genotoxic stress, during which bacteria can rearrange and mutate their genome, induce several phenotypic changes through differential regulation of genes, and sometimes acquire characteristics that potentiate bacterial survival and adaptation to changing environments. We review here the causes and consequences of SOS induction, but also how this response can be modulated under various circumstances and how it is connected to the network of other important stress responses. In the first section, we review articles describing the induction of the SOS response at the molecular level. The second section discusses consequences of this induction in terms of DNA repair, changes in the genome and gene expression, and sharing of genomic information, with their effects on the bacteria's life and evolution. The third section is about the fine tuning of this response to fit with the bacteria's 'needs'. Finally, we discuss recent findings linking the SOS response to other stress responses. Under these perspectives, SOS can be perceived as a powerful bacterial strategy against aggressions. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

NOAA NOS SOS, EXPERIMENTAL, 1853-present, Air Temperature

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have air temperature data. *These services are for testing and evaluation...

NOAA NOS SOS, EXPERIMENTAL, 1853-present, Water Temperature

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have water temperature data. *These services are for testing and evaluation...

Theoretical model of the SOS effect

Energy Technology Data Exchange (ETDEWEB)

Darznek, S A; Mesyats, G A; Rukin, S N; Tsiranov, S N [Russian Academy of Sciences, Ural Division, Ekaterinburg (Russian Federation). Institute of Electrophysics

1997-12-31

Physical principles underlying the operation of semiconductor opening switches (SOS) are highlighted. The SOS effect occurs at a current density of up to 60 kA/cm{sup 2} in silicon p{sup +}-p-n-n{sup +} structures filled with residual electron-hole plasma. Using a theoretical model developed for plasma dynamic calculations, the mechanism by which current passes through the structure at the stage of high conduction and the processes that take place at the stage of current interruption were analyzed. The dynamics of the processes taking place in the structure was calculated with allowance for both diffusive and drift mechanisms of carrier transport. In addition, two recombination types, viz. recombination via impurities and impact Auger recombination, were included in the model. The effect of the structure on the pumping-circuit current and voltage was also taken into account. The real distribution of the doped impurity in the structure and the avalanche mechanism of carrier multiplication were considered. The results of calculations of a typical SOS are presented. The dynamics of the electron-hole plasma is analyzed. It is shown that the SOS effect represents a qualitatively new mechanism of current interruption in semiconductor structures. (author). 4 figs., 7 refs.

NOAA NOS SOS, EXPERIMENTAL, 1853-present, Water Level

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have water surface height above a reference datum. *These services are for...

Investigation of potential genotoxic activity using the SOS Chromotest for real paracetamol wastewater and the wastewater treated by the Fenton process.

Science.gov (United States)

Kocak, Emel

2015-01-01

The potential genotoxic activity associated with high strength real paracetamol (PCT) wastewater (COD = 40,000 mg/L, TOC = 12,000 mg/L, BOD5 = 19,320 mg/L) from a large-scale drug-producing plant in the Marmara Region, was investigated in pre- and post- treated wastewater by the Fenton process (COD = 2,920 mg/L, TOC = 880 mg/L; BOD5 = 870 mg/L). The SOS Chromotest, which is based on Escherichia coli PQ37 activities, was used for the assessment of genotoxicity. The corrected induction factors (CIF) values used as quantitative measurements of the genotoxic activity were obtained from a total of four different dilutions (100, 50, 6.25, and 0.078 % v/v.) for two samples, in triplicate, to detect potentially genotoxic activities with the SOS Chromotest. The results of the SOS Chromotest demonstrated CIFmax value of 1.24, indicating that the PCT effluent (non-treated) is genotoxic. The results of the SOS Chromotest showed an CIFmax value of 1.72, indicating that the wastewater treated by Fenton process is genotoxic. The findings of this study clearly reveal that the PCT wastewater (non-treated) samples have a potentially hazardous impact on the aquatic environment before treatment, and in the wastewater that was treated by the Fenton process, genotoxicity generally increased.

SNAP/SOS: a package for simulating and analyzing safeguards systems

International Nuclear Information System (INIS)

Grant, F.H. III; Polito, J.; Sabuda, J.

1983-01-01

The effective analysis of safeguards systems at nuclear facilities requires significant effort. The Safeguards Network Analysis Procedure (SNAP) and the SNAP Operating System (SOS) reduce that effort to a manageable level. SNAP provides a detailed analysis of site safeguards for tactical evaluation. SOS helps the analyst organize and manage the SNAP effort effectively. SOS provides a database for model storage, automatic model generation, and computer graphics. The SOS/SNAP combination is a working example of a simulation system including executive-level control, database system, and facilities for model creation, editing, and output analysis

A novel Arabidopsis CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) mutant with enhanced pathogen-induced cell death and altered receptor processing.

Science.gov (United States)

Petutschnig, Elena K; Stolze, Marnie; Lipka, Ulrike; Kopischke, Michaela; Horlacher, Juliane; Valerius, Oliver; Rozhon, Wilfried; Gust, Andrea A; Kemmerling, Birgit; Poppenberger, Brigitte; Braus, Gerhard H; Nürnberger, Thorsten; Lipka, Volker

2014-12-01

Plants detect pathogens by sensing microbe-associated molecular patterns (MAMPs) through pattern recognition receptors. Pattern recognition receptor complexes also have roles in cell death control, but the underlying mechanisms are poorly understood. Here, we report isolation of cerk1-4, a novel mutant allele of the Arabidopsis chitin receptor CERK1 with enhanced defense responses. We identified cerk1-4 in a forward genetic screen with barley powdery mildew and consequently characterized it by pathogen assays, mutant crosses and analysis of defense pathways. CERK1 and CERK1-4 proteins were analyzed biochemically. The cerk1-4 mutation causes an amino acid exchange in the CERK1 ectodomain. Mutant plants maintain chitin signaling capacity but exhibit hyper-inducible salicylic acid concentrations and deregulated cell death upon pathogen challenge. In contrast to chitin signaling, the cerk1-4 phenotype does not require kinase activity and is conferred by the N-terminal part of the receptor. CERK1 undergoes ectodomain shedding, a well-known process in animal cell surface proteins. Wild-type plants contain the full-length CERK1 receptor protein as well as a soluble form of the CERK1 ectodomain, whereas cerk1-4 plants lack the N-terminal shedding product. Our work suggests that CERK1 may have a chitin-independent role in cell death control and is the first report of ectodomain shedding in plants. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

SOS reaction kinetics of bacterial cells induced by ultraviolet radiation and α particles

International Nuclear Information System (INIS)

Bonev, M.; Kolev, S.

2000-01-01

It is the purpose of the work to apply the SOS lux test for detecting α particles, as well as to study the SOS system kinetics. Two strains with plasmid pPLS-1 are used: wild type C600 lux and its isogen lysogen with α prophage one. Irradiation is done on dacron nuclear filters. The source of α particles is Am 241 with power 5 Gy/min, and the ultraviolet source - a lamp emitting rays with wave length 254 nm. The light yield is measured by installations made up of scintilometer VA-S-968, High-voltage electric power, and one channel analyzer Strahlugsmessgerat 20046. The SOS lux text is based on the recombinant plasmid pPLS-1 which is a derivative of pBR322 where the lux gene is set under the control of an SOS promoter. E coly recA + strains containing the construction produce considerable amount of photons in the visible zone following treatment with agents damaging the DNA of cells. The kinetic curves of SOS response are obtained after irradiation with α particles and UV rays. DNA damaging agents cause an increase in the initial SOS response rate in the range od smaller doses, and a decrease reaching to block of the one in the high doses range. The light yield of lysogenic cells is lower. As compared to nonelysogene ones. DNA damage caused by α particles are more difficult to repair as compared to pyrimidine dimers. (author)

Induction of the SOS system in Escherichia coli after UVA (320 - 400 nm) irradiation

International Nuclear Information System (INIS)

Batbyamba, G.; Drasil, V.

1988-01-01

Induction of the SOS repair system in E. coli caused by broad-band (320 - 400 nm) UVA radiation and an oxygen effect in this induction were studied using the sfiA::lacZ operon fusion. Moreover, an oxygen effect on the broad-band UVA radiation-induced cell killing was studied. The experiments indicate that: (1) Broad-band UVA light can produce lethal damage to cells as well as DNA damage able to generate an SOS-inducing signal. This damage is O 2 -dependent to a significant extent: SOSIP (O 2 )/ SOSIP (Ar) = 1.61 and OER = 1.96; (2) After UVA irradiation the SOS induction factor increases monotonously in the time interval longer than 4 h indicating that the SOS-inducing DNA damage caused by UVA irradiation has a 'long-lived' character; (3) Oxic and hypoxic incubation following UVA irradiation carried out under aerobic and anaerobic conditions resulted in a strong oxygen effect: SOSIP(O 2 )/SOSIP(Ar) ∼ 5. On the basis of these results and literary data it was concluded that one of the main toxic photoproducts formed as a result of UVA irradiation of the cells in a culture medium might be hydrogen peroxide (H 2 O 2 ). H 2 O 2 decays gradually during post-irradiation incubation and yields reactive radical species, mainly OH radical, that result in a formation of SOS-inducing DNA damages and contribute to cell lethality, and prolonged SOS induction. (author)

Gr and hp-1 tomato mutants unveil unprecedented interactions between arbuscular mycorrhizal symbiosis and fruit ripening.

Science.gov (United States)

Chialva, Matteo; Zouari, Inès; Salvioli, Alessandra; Novero, Mara; Vrebalov, Julia; Giovannoni, James J; Bonfante, Paola

2016-07-01

Systemic responses to an arbuscular mycorrhizal fungus reveal opposite phenological patterns in two tomato ripening mutants depending whether ethylene or light reception is involved. The availability of tomato ripening mutants has revealed many aspects of the genetics behind fleshy fruit ripening, plant hormones and light signal reception. Since previous analyses revealed that arbuscular mycorrhizal symbiosis influences tomato berry ripening, we wanted to test the hypothesis that an interplay might occur between root symbiosis and fruit ripening. With this aim, we screened seven tomato mutants affected in the ripening process for their responsiveness to the arbuscular mycorrhizal fungus Funneliformis mosseae. Following their phenological responses we selected two mutants for a deeper analysis: Green ripe (Gr), deficient in fruit ethylene perception and high-pigment-1 (hp-1), displaying enhanced light signal perception throughout the plant. We investigated the putative interactions between ripening processes, mycorrhizal establishment and systemic effects using biochemical and gene expression tools. Our experiments showed that both mutants, notwithstanding a normal mycorrhizal phenotype at root level, exhibit altered arbuscule functionality. Furthermore, in contrast to wild type, mycorrhization did not lead to a higher phosphate concentration in berries of both mutants. These results suggest that the mutations considered interfere with arbuscular mycorrhiza inducing systemic changes in plant phenology and fruits metabolism. We hypothesize a cross talk mechanism between AM and ripening processes that involves genes related to ethylene and light signaling.

The SOS Suicide Prevention Program: Further Evidence of Efficacy and Effectiveness.

Science.gov (United States)

Schilling, Elizabeth A; Aseltine, Robert H; James, Amy

2016-02-01

This study replicated and extended previous evaluations of the Signs of Suicide (SOS) prevention program in a high school population using a more rigorous pre-test post-test randomized control design than used in previous SOS evaluations in high schools (Aseltine and DeMartino 2004; Aseltine et al. 2007). SOS was presented to an ethnically diverse group of ninth grade students in technical high schools in Connecticut. After controlling for the pre-test reports of suicide behaviors, exposure to the SOS program was associated with significantly fewer self-reported suicide attempts in the 3 months following the program. Ninth grade students in the intervention group were approximately 64% less likely to report a suicide attempt in the past 3 months compared with students in the control group. Similarly, exposure to the SOS program resulted in greater knowledge of depression and suicide and more favorable attitudes toward (1) intervening with friends who may be exhibiting signs of suicidal intent and (2) getting help for themselves if they were depressed or suicidal. In addition, high-risk SOS participants, defined as those with a lifetime history of suicide attempt, were significantly less likely to report planning a suicide in the 3 months following the program compared to lower-risk participants. Differential attrition is the most serious limitation of the study; participants in the intervention group who reported a suicide attempt in the previous 3 months at baseline were more likely to be missing at post-test than their counterparts in the control group.

NOAA NDBC SOS, 2008-present, sea_floor_depth_below_sea_surface

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have sea_floor_depth_below_sea_surface data. Because of the nature of SOS...

Development of Plant Mutant Resources with an useful characters by Radiation Fusion Technology

International Nuclear Information System (INIS)

Kang, Si Yong; Kim, Dong Sub; Lee, Geung Joo

2009-02-01

A mutation breeding is to use physical or chemical mutagens to induce mutagenesis, followed by individual selections with favorable traits. The mutation breeding has many advantages over other breeding methods, which include the usefulness for improving one or two inferior characteristics, applications to broad species with different reproductive systems or to diverse plant materials, native or plant introduction with narrow genetic background, time and cost-effectiveness, and valuable mutant resources for genomics researches. Recent applications of the radiation breeding techniques to developments of flowering plants or food crops with improved functional constituents heightened the public's interests in agriculture and in our genetic resources and seed industries. The goals of this project, therefore, include achieving advances in domestic seed industries and agricultural productivities by developing and using new radiation mutants with favored traits, protecting an intellectual property right of domestic seeds or germplasms, and sharing the valuable mutants and mutated gene information for the genomics and biotech researches that eventually leads to economic benefits

Productive mutants in lemongrass induced by gamma rays

International Nuclear Information System (INIS)

Gopinathan Nair, V.

1980-01-01

Seeds of the lemongrass variety O.D. 19 were irradiated with gamma rays at a dose range of 5 to 30 krad. M 1 plants with one or a few tillers differing from the standard plants of O.D. 19 were selected, split into single slips and planted as clonal progenies. Mutants were isolated in M 1 V 1 and carried forward. Forty two M 1 V 2 mutant clones differing from O.D. 19 in morphological characters such as vigour, plant height, growth habit, pigmentation and number of tillers have been established. These were evaluated for tiller number, grass yield and oil content. Six clones gave higher grass yield, the highest being 556 gm per plant per cutting as against 360 gm in the standard. Five clones gave higher oil yield, the highest being 0.42% as against 0.23% in the standard. Isolation of viable mutants with high grass yield and essential oil content indicate the scope for evolving productive mutant varieties in this perennial aromatic grass. The eleven M 1 V 2 mutant clones are being critically evaluated by estimating oil yield per hectare per year. (author)

Ras activation by SOS: Allosteric regulation by altered fluctuation dynamics

Science.gov (United States)

Iversen, Lars; Tu, Hsiung-Lin; Lin, Wan-Chen; Christensen, Sune M.; Abel, Steven M.; Iwig, Jeff; Wu, Hung-Jen; Gureasko, Jodi; Rhodes, Christopher; Petit, Rebecca S.; Hansen, Scott D.; Thill, Peter; Yu, Cheng-Han; Stamou, Dimitrios; Chakraborty, Arup K.; Kuriyan, John; Groves, Jay T.

2014-01-01

Activation of the small guanosine triphosphatase H-Ras by the exchange factor Son of Sevenless (SOS) is an important hub for signal transduction. Multiple layers of regulation, through protein and membrane interactions, govern activity of SOS. We characterized the specific activity of individual SOS molecules catalyzing nucleotide exchange in H-Ras. Single-molecule kinetic traces revealed that SOS samples a broad distribution of turnover rates through stochastic fluctuations between distinct, long-lived (more than 100 seconds), functional states. The expected allosteric activation of SOS by Ras–guanosine triphosphate (GTP) was conspicuously absent in the mean rate. However, fluctuations into highly active states were modulated by Ras-GTP. This reveals a mechanism in which functional output may be determined by the dynamical spectrum of rates sampled by a small number of enzymes, rather than the ensemble average. PMID:24994643

A homozygous recA mutant of Synechocystis PCC6803: construction strategy and characteristics eliciting a novel RecA independent UVC resistance in dark.

Science.gov (United States)

Minda, Renu; Ramchandani, Jyoti; Joshi, Vasudha P; Bhattacharjee, Swapan Kumar

2005-12-01

We report here the construction of a homozygous recA460::cam insertion mutant of Synechocystis sp. PCC 6803 that may be useful for plant molecular genetics by providing a plant like host free of interference from homologous recombination. The homozygous recA460::cam mutant is highly sensitive to UVC under both photoreactivating and non-photoreactivating conditions compared to the wild type (WT). The liquid culture of the mutant growing in approximately 800 lx accumulates nonviable cells to the tune of 86% as estimated by colony counts on plates incubated at the same temperature and light intensity. The generation time of recA mutant in standard light intensity (2,500 lx) increases to 50 h compared to 28 h in lower light intensity (approximately 800 lx) that was used for selection, thus explaining the earlier failures to obtain a homozygous recA mutant. The WT, in contrast, grows at faster rate (23 h generation time) in standard light intensity compared to that at approximately 800 lx (26 h). The Synechocystis RecA protein supports homologous recombination during conjugation in recA (-) mutant of Escherichia coli, but not the SOS response as measured by UV sensitivity. It is suggested that using this homozygous recA460::cam mutant, investigations can now be extended to dissect the network of DNA repair pathways involved in housekeeping activities that may be more active in cyanobacteria than in heterotrophs. Using this mutant for the first time we provide a genetic evidence of a mechanism independent of RecA that causes enhanced UVC resistance on light to dark transition.

Adaptive symbiotic organisms search (SOS algorithm for structural design optimization

Directory of Open Access Journals (Sweden)

Ghanshyam G. Tejani

2016-07-01

Full Text Available The symbiotic organisms search (SOS algorithm is an effective metaheuristic developed in 2014, which mimics the symbiotic relationship among the living beings, such as mutualism, commensalism, and parasitism, to survive in the ecosystem. In this study, three modified versions of the SOS algorithm are proposed by introducing adaptive benefit factors in the basic SOS algorithm to improve its efficiency. The basic SOS algorithm only considers benefit factors, whereas the proposed variants of the SOS algorithm, consider effective combinations of adaptive benefit factors and benefit factors to study their competence to lay down a good balance between exploration and exploitation of the search space. The proposed algorithms are tested to suit its applications to the engineering structures subjected to dynamic excitation, which may lead to undesirable vibrations. Structure optimization problems become more challenging if the shape and size variables are taken into account along with the frequency. To check the feasibility and effectiveness of the proposed algorithms, six different planar and space trusses are subjected to experimental analysis. The results obtained using the proposed methods are compared with those obtained using other optimization methods well established in the literature. The results reveal that the adaptive SOS algorithm is more reliable and efficient than the basic SOS algorithm and other state-of-the-art algorithms.

Enhanced Abscisic Acid-Mediated Responses in nia1nia2noa1-2 Triple Mutant Impaired in NIA/NR- and AtNOA1-Dependent Nitric Oxide Biosynthesis in Arabidopsis1[W

Science.gov (United States)

Lozano-Juste, Jorge; León, José

2010-01-01

Nitric oxide (NO) regulates a wide range of plant processes from development to environmental adaptation. Despite its reported regulatory functions, it remains unclear how NO is synthesized in plants. We have generated a triple nia1nia2noa1-2 mutant that is impaired in nitrate reductase (NIA/NR)- and Nitric Oxide-Associated1 (AtNOA1)-mediated NO biosynthetic pathways. NO content in roots of nia1nia2 and noa1-2 plants was lower than in wild-type plants and below the detection limit in nia1nia2noa1-2 plants. NIA/NR- and AtNOA1-mediated biosynthesis of NO were thus active and responsible for most of the NO production in Arabidopsis (Arabidopsis thaliana). The nia1nia2noa1-2 plants displayed reduced size, fertility, and seed germination potential but increased dormancy and resistance to water deficit. The increasing deficiency in NO of nia1nia2, noa1-2, and nia1nia2noa1-2 plants correlated with increased seed dormancy, hypersensitivity to abscisic acid (ABA) in seed germination and establishment, as well as dehydration resistance. In nia1nia2noa1-2 plants, enhanced drought tolerance was due to a very efficient stomata closure and inhibition of opening by ABA, thus uncoupling NO from ABA-triggered responses in NO-deficient guard cells. The NO-deficient mutants in NIA/NR- and AtNOA1-mediated pathways in combination with the triple mutant will be useful tools to functionally characterize the role of NO and the contribution of both biosynthetic pathways in regulating plant development and defense. PMID:20007448

Transcriptome changes associated wtih delayed flower senescence on transgenic petunia by inducing expression of etr1-1, a mutant ethylene receptor

Science.gov (United States)

Flowers of ethylene-sensitive ornamental plants transformed with ethylene-insensitive 1-1(etr 1-1), a mutant ethylene receptor first isolated from Arabidopsis, are known to have longer shelf lives. We have generated petunia plants in which the etr 1-1 gene was over-expressed under the control of a c...

Multiple spinal nerve enlargement and SOS1 mutation: Further evidence of overlap between neurofibromatosis type 1 and Noonan phenotype.

Science.gov (United States)

Santoro, C; Giugliano, T; Melone, M A B; Cirillo, M; Schettino, C; Bernardo, P; Cirillo, G; Perrotta, S; Piluso, G

2018-01-01

Neurofibromatosis type 1 (NF1) has long been considered a well-defined, recognizable monogenic disorder, with neurofibromas constituting a pathognomonic sign. This dogma has been challenged by recent descriptions of patients with enlarged nerves or paraspinal tumors, suggesting that neurogenic tumors and hypertrophic neuropathy may be a complication of Noonan syndrome with multiple lentigines (NSML) or RASopathy phenotype. We describe a 15-year-old boy, whose mother previously received clinical diagnosis of NF1 due to presence of bilateral cervical and lumbar spinal lesions resembling plexiform neurofibromas and features suggestive of NS. NF1 molecular analysis was negative in the mother. The boy presented with Noonan features, multiple lentigines and pectus excavatum. Next-generation sequencing analysis of all RASopathy genes identified p.Ser548Arg missense mutation in SOS1 in the boy, confirmed in his mother. Brain and spinal magnetic resonance imaging scans were negative in the boy. No heart involvement or deafness was observed in proband or mother. This is the first report of a SOS1 mutation associated with hypertrophic neuropathy resembling plexiform neurofibromas, a rare complication in Noonan phenotypes with mutations in RASopathy genes. Our results highlight the overlap between RASopathies, suggesting that NF1 diagnostic criteria need rethinking. Genetic analysis of RASopathy genes should be considered when diagnosis is uncertain. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

High-throughput screening identifies small molecules that bind to the RAS:SOS:RAS complex and perturb RAS signaling.

Science.gov (United States)

Burns, Michael C; Howes, Jennifer E; Sun, Qi; Little, Andrew J; Camper, DeMarco V; Abbott, Jason R; Phan, Jason; Lee, Taekyu; Waterson, Alex G; Rossanese, Olivia W; Fesik, Stephen W

2018-05-01

K-RAS is mutated in approximately 30% of human cancers, resulting in increased RAS signaling and tumor growth. Thus, RAS is a highly validated therapeutic target, especially in tumors of the pancreas, lung and colon. Although directly targeting RAS has proven to be challenging, it may be possible to target other proteins involved in RAS signaling, such as the guanine nucleotide exchange factor Son of Sevenless (SOS). We have previously reported on the discovery of small molecules that bind to SOS1, activate SOS-mediated nucleotide exchange on RAS, and paradoxically inhibit ERK phosphorylation (Burns et al., PNAS, 2014). Here, we describe the discovery of additional, structurally diverse small molecules that also bind to SOS1 in the same pocket and elicit similar biological effects. We tested >160,000 compounds in a fluorescence-based assay to assess their effects on SOS-mediated nucleotide exchange. X-Ray structures revealed that these small molecules bind to the CDC25 domain of SOS1. Compounds that elicited high levels of nucleotide exchange activity in vitro increased RAS-GTP levels in cells, and inhibited phospho ERK levels at higher treatment concentrations. The identification of structurally diverse SOS1 binding ligands may assist in the discovery of new molecules designed to target RAS-driven tumors. Copyright © 2018 Elsevier Inc. All rights reserved.

SOS response and its regulation on the fluoroquinolone resistance.

Science.gov (United States)

Qin, Ting-Ting; Kang, Hai-Quan; Ma, Ping; Li, Peng-Peng; Huang, Lin-Yan; Gu, Bing

2015-12-01

Bacteria can survive fluoroquinolone antibiotics (FQs) treatment by becoming resistant through a genetic change-mutation or gene acquisition. The SOS response is widespread among bacteria and exhibits considerable variation in its composition and regulation, which is repressed by LexA protein and derepressed by RecA protein. Here, we take a comprehensive review of the SOS gene network and its regulation on the fluoroquinolone resistance. As a unique survival mechanism, SOS may be an important factor influencing the outcome of antibiotic therapy in vivo.

Evidence for a Ustilago maydis Steroid 5α-Reductase by Functional Expression in Arabidopsis det2-1 Mutants1

Science.gov (United States)

Basse, Christoph W.; Kerschbamer, Christine; Brustmann, Markus; Altmann, Thomas; Kahmann, Regine

2002-01-01

We have identified a gene (udh1) in the basidiomycete Ustilago maydis that is induced during the parasitic interaction with its host plant maize (Zea mays). udh1 encodes a protein with high similarity to mammalian and plant 5α-steroid reductases. Udh1 differs from those of known 5α-steroid reductases by six additional domains, partially predicted to be membrane-spanning. A fusion protein of Udh1 and the green fluorescent protein provided evidence for endoplasmic reticulum localization in U. maydis. The function of the Udh1 protein was demonstrated by complementing Arabidopsis det2-1 mutants, which display a dwarf phenotype due to a mutation in the 5α-steroid reductase encoding DET2 gene. det2-1 mutant plants expressing either the udh1 or the DET2 gene controlled by the cauliflower mosaic virus 35S promoter differed from wild-type Columbia plants by accelerated stem growth, flower and seed development and a reduction in size and number of rosette leaves. The accelerated growth phenotype of udh1 transgenic plants was stably inherited and was favored under reduced light conditions. Truncation of the N-terminal 70 amino acids of the Udh1 protein abolished the ability to restore growth in det2-1 plants. Our results demonstrate the existence of a 5α-steroid reductase encoding gene in fungi and suggest a common ancestor between fungal, plant, and mammalian proteins. PMID:12068114

Mapping Modular SOS to Rewriting Logic

DEFF Research Database (Denmark)

Braga, Christiano de Oliveira; Haeusler, Erik Hermann; Meseguer, José

Modular SOS (MSOS) is a framework created to improve the modularity of structural operational semantics specifications, a formalism frequently used in the fields of programming languages semantics and process algebras. With the objective of defining formal tools to support the execution and verif......Modular SOS (MSOS) is a framework created to improve the modularity of structural operational semantics specifications, a formalism frequently used in the fields of programming languages semantics and process algebras. With the objective of defining formal tools to support the execution...

Mapping Modular SOS to Rewriting Logic

DEFF Research Database (Denmark)

Braga, Christiano de Oliveira; Haeusler, Edward Hermann; Meseguer, José

2003-01-01

Modular SOS (MSOS) is a framework created to improve the modularity of structural operational semantics specifications, a formalism frequently used in the fields of programming languages semantics and process algebras. With the objective of defining formal tools to support the execution and verif......Modular SOS (MSOS) is a framework created to improve the modularity of structural operational semantics specifications, a formalism frequently used in the fields of programming languages semantics and process algebras. With the objective of defining formal tools to support the execution...

Arabidopsis thaliana cdd1 mutant uncouples the constitutive activation of salicylic acid signalling from growth defects.

Science.gov (United States)

Swain, Swadhin; Roy, Shweta; Shah, Jyoti; Van Wees, Saskia; Pieterse, Corné M; Nandi, Ashis K

2011-12-01

Arabidopsis genotypes with a hyperactive salicylic acid-mediated signalling pathway exhibit enhanced disease resistance, which is often coupled with growth and developmental defects, such as dwarfing and spontaneous necrotic lesions on the leaves, resulting in reduced biomass yield. In this article, we report a novel recessive mutant of Arabidopsis, cdd1 (constitutive defence without defect in growth and development1), that exhibits enhanced disease resistance associated with constitutive salicylic acid signalling, but without any observable pleiotropic phenotype. Both NPR1 (NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES1)-dependent and NPR1-independent salicylic acid-regulated defence pathways are hyperactivated in cdd1 mutant plants, conferring enhanced resistance against bacterial pathogens. However, a functional NPR1 allele is required for the cdd1-conferred heightened resistance against the oomycete pathogen Hyaloperonospora arabidopsidis. Salicylic acid accumulates at elevated levels in cdd1 and cdd1 npr1 mutant plants and is necessary for cdd1-mediated PR1 expression and disease resistance phenotypes. In addition, we provide data which indicate that the cdd1 mutation negatively regulates the npr1 mutation-induced hyperactivation of ethylene/jasmonic acid signalling. © 2011 The Authors. Molecular Plant Pathology © 2011 BSPP and Blackwell Publishing Ltd.

Genetical, cytological and physiological studies on the induced mutants with special regard to effective methods for obtaining useful mutants in perennial woody plant

International Nuclear Information System (INIS)

Kukimura, H.; Ikeda, F.; Fujita, H.; Maeta, T.; Nakajima, K.; Katagiri, K.; Nakahira, K.; Somegou, M.

1976-01-01

The plants studied included apple trees, cryptomeria (japanese cedar) and mulberry. In apple, dwarf and compact types of mutants from cv. Fuji were found to be graft incompatible on Maruba-kaido(Malus prunifolia) rootstock. In Sunki mandarin(Citrus sunki), the number of nucellar embryo per seed was affected by gamma-irradiation, and morphological mutants from nucellar seedlings were obtained at high rate by irradiation at floral bud stage with 2kR exposure. In Cryptomeria, re-irradiated waxless mutants by gamma-rays showed very high rate of somatic mutation when compared to other morphological mutants. Pollen sterility and pollen shaped PMC were found in the most of gamma-induced-mutants. Mutants forming pollen shaped PMC had a genetical tendency of continuous male flower bud formation for a longer term. With mulberry, time of sprouting of induced mutants differed from the originals. Ability of root initiation of semi-softwood cuttings in morphological mutants were tested. Cytochimera induction were found at considerably high rate when actively growing diploid plants were irradiated by gamma-rays. Eight kinds of cytochimeras were induced. Frequency of 2-4-4 was extremely high(approx. 50%), then 4-2-2 and 2-4-2 chimeras followed. Seven kinds were induced by semi-acute irradiation(200R/h), while 4 kinds by acute irradiation(5kR/h). By breeding test it was cleared that the elongate and entire leaf was sexually transmissible, whereas the 'dwarf' was not obvious and the 'marginally curledleaf' was not transmissible. Pyronin-methylgreen staining method proved to be useful in some morphological mutants to distinguish the histo-genetical differences which exist in the shoot apex.

Differential disease resistance response in the barley necrotic mutant nec1

Directory of Open Access Journals (Sweden)

Kunga Laura

2011-04-01

Full Text Available Abstract Background Although ion fluxes are considered to be an integral part of signal transduction during responses to pathogens, only a few ion channels are known to participate in the plant response to infection. CNGC4 is a disease resistance-related cyclic nucleotide-gated ion channel. Arabidopsis thaliana CNGC4 mutants hlm1 and dnd2 display an impaired hypersensitive response (HR, retarded growth, a constitutively active salicylic acid (SA-mediated pathogenesis-related response and elevated resistance against bacterial pathogens. Barley CNGC4 shares 67% aa identity with AtCNGC4. The barley mutant nec1 comprising of a frame-shift mutation of CNGC4 displays a necrotic phenotype and constitutively over-expresses PR-1, yet it is not known what effect the nec1 mutation has on barley resistance against different types of pathogens. Results nec1 mutant accumulated high amount of SA and hydrogen peroxide compared to parental cv. Parkland. Experiments investigating nec1 disease resistance demonstrated positive effect of nec1 mutation on non-host resistance against Pseudomonas syringae pv. tomato (Pst at high inoculum density, whereas at normal Pst inoculum concentration nec1 resistance did not differ from wt. In contrast to augmented P. syringae resistance, penetration resistance against biotrophic fungus Blumeria graminis f. sp. hordei (Bgh, the causal agent of powdery mildew, was not altered in nec1. The nec1 mutant significantly over-expressed race non-specific Bgh resistance-related genes BI-1 and MLO. Induction of BI-1 and MLO suggested putative involvement of nec1 in race non-specific Bgh resistance, therefore the effect of nec1on mlo-5-mediated Bgh resistance was assessed. The nec1/mlo-5 double mutant was as resistant to Bgh as Nec1/mlo-5 plants, suggesting that nec1 did not impair mlo-5 race non-specific Bgh resistance. Conclusions Together, the results suggest that nec1 mutation alters activation of systemic acquired resistance

Genetics of leaf rust-resistant mutant WH 147-LM-1 in hexaploid wheat variety WH 147

International Nuclear Information System (INIS)

Reddy, V.R.K.; Viswanathan, P.

1999-01-01

By applying gamma rays, EMS and their combination in hexaploid wheat variety WH 147, a total of 20 mutants (0.0226%) exhibiting complete leaf rust resistance were isolated from segregating M2 rows.When one of the rust-resistant mutants, WH 147-LM-1 was crossed with the universally susceptible, suggesting that the mutant character is controlled by one dominant gene and one recessive gene.The F2 plants derived by crossing the mutant WH 147-LM with seven near-isogenic wheat lines showed segregation for susceptibility, indicating that the mutant character was indeed generated through induced mutations

SOS - Der kaldes på Smartere Offentlig Styring

DEFF Research Database (Denmark)

Hjortdal, Henrik

2017-01-01

Smartere Offentlig Styring eller SOS. Det var temaet da over hundrede kommunale direktører drøftede offentlig ledelse med en lang række toneangivende danske forskere.......Smartere Offentlig Styring eller SOS. Det var temaet da over hundrede kommunale direktører drøftede offentlig ledelse med en lang række toneangivende danske forskere....

Plant cells without detectable plastids are generated in the crumpled leaf mutant of Arabidopsis thaliana.

Science.gov (United States)

Chen, Yuling; Asano, Tomoya; Fujiwara, Makoto T; Yoshida, Shigeo; Machida, Yasunori; Yoshioka, Yasushi

2009-05-01

Plastids are maintained in cells by proliferating prior to cell division and being partitioned to each daughter cell during cell division. It is unclear, however, whether cells without plastids are generated when plastid division is suppressed. The crumpled leaf (crl) mutant of Arabidopsis thaliana is a plastid division mutant that displays severe abnormalities in plastid division and plant development. We show that the crl mutant contains cells lacking detectable plastids; this situation probably results from an unequal partitioning of plastids to each daughter cell. Our results suggest that crl has a partial defect in plastid expansion, which is suggested to be important in the partitioning of plastids to daughter cells when plastid division is suppressed. The absence of cells without detectable plastids in the accumulation and replication of chloroplasts 6 (arc6) mutant, another plastid division mutant of A. thaliana having no significant defects in plant morphology, suggests that the generation of cells without detectable plastids is one of the causes of the developmental abnormalities seen in crl plants. We also demonstrate that plastids with trace or undetectable amounts of chlorophyll are generated from enlarged plastids by a non-binary fission mode of plastid replication in both crl and arc6.

Analysis of AtCry1 and Mutants

Science.gov (United States)

Burdick, Derek; Purvis, Adam; Ahmad, Margaret; Link, Justin J.; Engle, Dorothy

Cryptochrome is an incredibly versatile protein that influences numerous biological processes such as plant growth, bird migration, and sleep cycles. Due to the versatility of this protein, understanding the mechanism would allow for advances in numerous fields such as crop growth, animal behavior, and sleep disorders. It is known that cryptochrome requires blue light to function, but the exact processes in the regulation of biological activity are still not fully understood. It is believed that the c-terminal domain of the protein undergoes a conformational change when exposed to blue light which allows for biological function. Three different non-functioning mutants were tested during this study to gain insight on the mechanism of cryptochrome. Absorbance spectra showed a difference between two of the mutants and the wild type with one mutant showing little difference. Immunoprecipitation experiments were also conducted to identify the different c-terminal responses of the mutants. By studying non functioning mutants of this protein, the mechanism of the protein can be further characterized. This two-month research experience in Paris allowed us to experience international and interdisciplinary collaborations in science and immerse in a different culture. The Borcer Fund for Student Research, Xavier University, Cincinnati, OH, and John Hauck Foundation.

Stent-over-sponge (SOS): a novel technique complementing endosponge therapy for foregut leaks and perforations.

Science.gov (United States)

Valli, Piero V; Mertens, Joachim C; Kröger, Arne; Gubler, Christoph; Gutschow, Christian; Schneider, Paul M; Bauerfeind, Peter

2018-02-01

 Endoluminal vacuum therapy (EVT) has evolved as a promising option for endoscopic treatment of foregut wall injuries in addition to the classic closure techniques using clips or stents. To improve vacuum force and maintain esophageal passage, we combined endosponge treatment with a partially covered self-expandable metal stent (stent-over-sponge; SOS).  Twelve patients with infected upper gastrointestinal wall defects were treated with the SOS technique.  Indications for SOS were anastomotic leakage after surgery (n = 11) and chronic foregut fistula (n = 1). SOS treatment was used as a first-line treatment in seven patients with a success rate of 71.4 % (5/7) and as a second-line treatment after failed previous EVT treatment in five patients (success rate 80 %; 4/5). Overall, SOS treatment was successful in 75 % of patients (9/12). No severe adverse events occurred. CONCLUSION : SOS is an effective method to treat severely infected foregut wall defects in patients where EVT has failed, and also as a first-line treatment. Comparative prospective studies are needed to confirm our preliminary results. © Georg Thieme Verlag KG Stuttgart · New York.

Suppression of the UV-sensitive phenotype of Escherichia coli recF mutants by recA(Srf) and recA(Tif) mutations requires recJ+

International Nuclear Information System (INIS)

Thoms, B.; Wackernagel, W.

1988-01-01

Mutations in recA, such as recA801(Srf) (suppressor of RecF) or recA441(Tif) (temperature-induced filamentation) partially suppress the deficiency in postreplication repair of UV damage conferred by recF mutations. We observed that spontaneous recA(Srf) mutants accumulated in cultures of recB recC sbcB sulA::Mu dX(Ap lac) lexA51 recF cells because they grew faster than the parental strain. We show that in a uvrA recB+ recC+ genetic background there are two prerequisites for the suppression by recA(Srf) of the UV-sensitive phenotype of recF mutants. (i) The recA(Srf) protein must be provided in increased amounts either by SOS derepression or by a recA operator-constitutive mutation in a lexA(Ind) (no induction of SOS functions) genetic background. (ii) The gene recJ, which has been shown previously to be involved in the recF pathway of recombination and repair, must be functional. The level of expression of recJ in a lexA(Ind) strain suffices for full suppression. Suppression by recA441 at 30 degrees C also depends on recJ+. The hampered induction by UV of the SOS gene uvrA seen in a recF mutant was improved by a recA(Srf) mutation. This improvement did not require recJ+. We suggest that recA(Srf) and recA(Tif) mutant proteins can operate in postreplication repair independent of recF by using the recJ+ function

Advances/applications of MAGIC and SOS

Science.gov (United States)

Warren, Gary; Ludeking, Larry; Nguyen, Khanh; Smithe, David; Goplen, Bruce

1993-12-01

MAGIC and SOS have been applied to investigate a variety of accelerator-related devices. Examples include high brightness electron guns, beam-RF interactions in klystrons, cold-test modes in an RFQ and in RF sources, and a high-quality, flexible, electron gun with operating modes appropriate for gyrotrons, peniotrons, and other RF sources. Algorithmic improvements for PIC have been developed and added to MAGIC and SOS to facilitate these modeling efforts. Two new field algorithms allow improved control of computational numerical noise and selective control of harmonic modes in RF cavities. An axial filter in SOS accelerates simulations in cylindrical coordinates. The recent addition of an export/import feature now allows long devices to be modeled in sections. Interfaces have been added to receive electromagnetic field information from the Poisson group of codes and from EGUN and to send beam information to PARMELA for subsequent tracing of bunches through beam optics. Post-processors compute and display beam properties including geometric, normalized, and slice emittances, and phase-space parameters, and video. VMS, UNIX, and DOS versions are supported, with migration underway toward windows environments.

Mechanical touch responses of Arabidopsis TCH1-3 mutant roots on inclined hard-agar surface

Science.gov (United States)

Zha, Guodong; Wang, Bochu; Liu, Junyu; Yan, Jie; Zhu, Liqing; Yang, Xingyan

2016-01-01

The gravity-induced mechanical touch stimulus can affect plant root architecture. Mechanical touch responses of plant roots are an important aspect of plant root growth and development. Previous studies have reported that Arabidopsis TCH1-3 genes are involved in mechano-related events, how-ever, the physiological functions of TCH1-3 genes in Arabidopsis root mechanoresponses remain unclear. In the present study, we applied an inclined hard agar plate method to produce mechanical touch stimulus, and provided evidence that altered mechanical environment could influence root growth. Furthermore, tch1-3 Arabidopsis mutants were investigated on inclined agar surfaces to explore the functions of TCH1-3 genes on Arabidopsis root mechanoresponses. The results showed that two tch2 mutants, cml24-2 and cml24-4, exhibited significantly reduced root length, biased skewing, and decreased density of lateral root. In addition, primary root length and density of lateral root of tch3 (cml12-2) was significantly decreased on inclined agar surfaces. This study indicates that the tch2 and tch3 mutants are hypersensitive to mechanical touch stimulus, and TCH2 (CML24-2 and CML24-4) and TCH3 (CML12-2) genes may participate in the mechanical touch response of Arabidopsis roots.

Inhibitors of LexA Autoproteolysis and the Bacterial SOS Response Discovered by an Academic-Industry Partnership.

Science.gov (United States)

Mo, Charlie Y; Culyba, Matthew J; Selwood, Trevor; Kubiak, Jeffrey M; Hostetler, Zachary M; Jurewicz, Anthony J; Keller, Paul M; Pope, Andrew J; Quinn, Amy; Schneck, Jessica; Widdowson, Katherine L; Kohli, Rahul M

2018-03-09

The RecA/LexA axis of the bacterial DNA damage (SOS) response is a promising, yet nontraditional, drug target. The SOS response is initiated upon genotoxic stress, when RecA, a DNA damage sensor, induces LexA, the SOS repressor, to undergo autoproteolysis, thereby derepressing downstream genes that can mediate DNA repair and accelerate mutagenesis. As genetic inhibition of the SOS response sensitizes bacteria to DNA damaging antibiotics and decreases acquired resistance, inhibitors of the RecA/LexA axis could potentiate our current antibiotic arsenal. Compounds targeting RecA, which has many mammalian homologues, have been reported; however, small-molecules targeting LexA autoproteolysis, a reaction unique to the prokaryotic SOS response, have remained elusive. Here, we describe the logistics and accomplishments of an academic-industry partnership formed to pursue inhibitors against the RecA/LexA axis. A novel fluorescence polarization assay reporting on RecA-induced self-cleavage of LexA enabled the screening of 1.8 million compounds. Follow-up studies on select leads show distinct activity patterns in orthogonal assays, including several with activity in cell-based assays reporting on SOS activation. Mechanistic assays demonstrate that we have identified first-in-class small molecules that specifically target the LexA autoproteolysis step in SOS activation. Our efforts establish a realistic example for navigating academic-industry partnerships in pursuit of anti-infective drugs and offer starting points for dedicated lead optimization of SOS inhibitors that could act as adjuvants for current antibiotics.

Biochemical analysis of plant protection afforded by a nonpathogenic endophytic mutant of Colletotrichum magna

Energy Technology Data Exchange (ETDEWEB)

Redman, R.S.; Rodriguez, R.J. (Geological Survey, Seattle, WA (United States) Univ. of Washington, Seattle, WA (United States). Dept. of Botany); Clifton, D.R.; Morrel, J.; Brown, G. (Geological Survey, Seattle, WA (United States)); Freeman, S. (Volcani Center, Bet Dagan (Israel). Dept. of Plant Pathology)

1999-02-01

A nonpathogenic mutant of Colletotrichum magna (path-1) was previously shown to protect watermelon (Citrullus lanatus) and cucumber (Cucumis sativus) seedlings from anthracnose disease elicited by wild-type C. magna. Disease protection was observed in stems of path-1-colonized cucurbits but not in cotyledons, indicating that path-1 conferred tissue-specific and/or localized protection. Plant biochemical indicators of a localized and systemic (peroxidase, phenylalanine ammonia-lyase, lignin, and salicylic acid) plant-defense response were investigated in anthracnose-resistant and-susceptible cultivars of cucurbit seedlings exposed to four treatments: (1) water (control), (2) path-1 conidia, (3) wild-type conidia, and (4) challenge conditions (inoculation into path-1 conidia for 48 h and then exposure to wild-type conidia). Collectively, these analyses indicated that disease protection in path-1-colonized plants was correlated with the ability of these plants to mount a defense response more rapidly and to equal or greater levels than plants exposed to wild-type C. magna alone. Watermelon plants colonized with path-1 were also protected against disease caused by Colletotrichum orbiculare and Fusarium oxysporum. A model based on the kinetics of plant-defense activation is presented to explain the mechanism of path-1-conferred disease protection.

Recovery from ultraviolet light-induced inhibition of DNA synthesis requires umuDC gene products in recA718 mutant strains but not in recA+ strains of Escherichia coli

International Nuclear Information System (INIS)

Witkin, E.M.; Roegner-Maniscalco, V.; Sweasy, J.B.; McCall, J.O.

1987-01-01

Ultraviolet light (UV) inhibits DNA replication in Eschericia coli and induces the SOS response, a set of survival-enhancing phenotypes due to derepression of DNA damage-inducible genes, including recA and umuDC. Recovery of DNA synthesis after UV irradiation (induced replisome reactivation, or IRR) is an SOS function requiring RecA protein and postirradiation synthesis of additional protein(s), but this recovery does not require UmuDC protein. IRR occurs in strains carrying either recA718 (which does not reduce recombination, SOS inducibility, or UV mutagenesis) or umuC36 (which eliminates UV mutability), but not in recA718 umuC36 double mutants. In recA430 mutant strains, IRR does not occur whether or not functional UmuDC protein is present. IRR occurs in lexA-(Ind-) (SOS noninducible) strains if they carry an operator-constitutive recA allele and are allowed to synthesize proteins after irradiation. We conclude the following: (i) that UmuDC protein corrects or complements a defect in the ability of RecA718 protein (but not of RecA430 protein) to promote IRR and (ii) that in lexA(Ind-) mutant strains, IRR requires amplification of RecA+ protein (but not of any other LexA-repressed protein) plus post-UV synthesis of at least one other protein not controlled by LexA protein. We discuss the results in relation to the essential, but unidentified, roles of RecA and UmuDC proteins in UV mutagenesis

An extra early mutant of pigeonpea

International Nuclear Information System (INIS)

Ravikesavan, R.; Kalaimagal, T.; Rathnaswamy, R.

2001-01-01

The redgram (Cajanus cajan (L.) Huth) variety 'Prabhat DT' was gamma irradiated with 100, 200, 300 and 400 Gy doses. Several mutants have been identified viz., extra early mutants, monostem mutants, obcordifoliate mutants and bi-stigmatic mutants. The extra early mutant was obtained when treated with 100 Gy dose. The mutant was selfed and forwarded from M 2 to M 4 generation. In the M 4 generation the mutant line was raised along with the parental variety. Normal cultural practices were followed and the biometrical observations were recorded. It was observed that for the characters viz., total number of branches per plant, number of pods per plants, seeds per pod, 100 seed weight and seed yield per plant there was no difference between the mutant and parent variety. Whereas, regarding the days to flowering and maturity the mutants were earlier than the parents. The observation was recorded from two hundred plants each. The mutant gives the same yield in 90 days as that of the parent variety in 107 days, which make it an economic mutant

Evaluation of some mutant lines of rice induced by gamma radiation treatment 1. mean performance of rice mutants in M4 generation

International Nuclear Information System (INIS)

El-Banna, M.N.; El-Wakil, H.M.F.; Ebaid, R.A.; Sallam, R.A.

2009-01-01

Grains of eight rice mutants; SC 1, SC 6, RTY 1, RTY 3, HY 14, HYI 17, EH 4 and HYPI 22 were secured from Botany Department Faculty of Agriculture Cairo university. The procedures and the methodology for induction these mutants as well as the original mean performance of such mutants are presented else where; Sabbour, (1989) and Sabbour etal. (2002). Grains were sown (M4 generation) at the experimental farm in Itai EI-Baroud Agricultural Research Station Behaira Governorate Agricultural Research Center (ARC) in the summer season (2007). The mean performance of such mutants was studied during M4 generation. The most exciting results were as follows: the selected line SC 1 showed in M4 generation superior agronomic and yield traits. Sc 1 mutant line is not bred truly and it need more generations to reach stability. SC 6 in M4 generation showed considerable number of individuals scored low mean values toward the negative direction and lowering the overall trait mean performance. The rice lines RTY 1 and RTY 3 proved that, the average number of fertile tillers per plant of the selected lines maintained previously recorded mean values of M3 generation in M4. The traits showed significant differences among their progeny that recorded high CV% values as compared with those showed no significant differences. The rice lines HY 14 and HYI 17 showed a true breeding signs and no more breeding generations are required. Rice lines EH 4, showed a considerable reduction in number of days elapsed from date of cultivation till harvest. As, this mutant maintained 86.58 days till heading. Rice mutant line HYPI 22 did not bred truly for the original selected traits (high yield and high protein content) and it still need more generations of selection to reach considerable stability

Systematically Altering Bacterial SOS Activity under Stress Reveals Therapeutic Strategies for Potentiating Antibiotics.

Science.gov (United States)

Mo, Charlie Y; Manning, Sara A; Roggiani, Manuela; Culyba, Matthew J; Samuels, Amanda N; Sniegowski, Paul D; Goulian, Mark; Kohli, Rahul M

2016-01-01

The bacterial SOS response is a DNA damage repair network that is strongly implicated in both survival and acquired drug resistance under antimicrobial stress. The two SOS regulators, LexA and RecA, have therefore emerged as potential targets for adjuvant therapies aimed at combating resistance, although many open questions remain. For example, it is not well understood whether SOS hyperactivation is a viable therapeutic approach or whether LexA or RecA is a better target. Furthermore, it is important to determine which antimicrobials could serve as the best treatment partners with SOS-targeting adjuvants. Here we derived Escherichia coli strains that have mutations in either lexA or recA genes in order to cover the full spectrum of possible SOS activity levels. We then systematically analyzed a wide range of antimicrobials by comparing the mean inhibitory concentrations (MICs) and induced mutation rates for each drug-strain combination. We first show that significant changes in MICs are largely confined to DNA-damaging antibiotics, with strains containing a constitutively repressed SOS response impacted to a greater extent than hyperactivated strains. Second, antibiotic-induced mutation rates were suppressed when SOS activity was reduced, and this trend was observed across a wider spectrum of antibiotics. Finally, perturbing either LexA or RecA proved to be equally viable strategies for targeting the SOS response. Our work provides support for multiple adjuvant strategies, while also suggesting that the combination of an SOS inhibitor with a DNA-damaging antibiotic could offer the best potential for lowering MICs and decreasing acquired drug resistance. IMPORTANCE Our antibiotic arsenal is becoming depleted, in part, because bacteria have the ability to rapidly adapt and acquire resistance to our best agents. The SOS pathway, a widely conserved DNA damage stress response in bacteria, is activated by many antibiotics and has been shown to play central role in

Semi-dwarf mutant lines of hexaploid triticale

International Nuclear Information System (INIS)

Pidra, M.

1989-01-01

A spring form of hexaploid secondary triticale ADD 143/71, bred by MOGILEVA at the Plant Breeding Station at Uhretice was used for the mutagen treatment. The mutation experiment started in 1979. Seeds were treated with a 0.8 mM water solution of N-methyl-N-nitrosourea (MNH) (CETL and RELICHOVA, unpublished). From 180 M 1 plants, one spike was harvested per plant. A random sample of these seeds was sown as M 2 in 1980 and several plants with shorter main culm were selected. Selfed progenies of eight mutant plants designated ADD 143-m1, ADD 143-m2, ADD 143-m3 etc. were further tested in M 3 and M 4 . There were significant differences in culm length and in some other characters between the original line and the mutant lines. Especially the line m8 looks like a promising source of semi-dwarfness for breeding programmes of hexaploid triticale. During 1985-1987 genetic analysis was performed on the ADD 143/71 and the mutant lines m2, m6, m7 and m8, which suggest that their mutant genes are allelic and recessive

Analysis of the SOS response of Vibrio and other bacteria with multiple chromosomes

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Sanchez-Alberola Neus

2012-02-01

Full Text Available Abstract Background The SOS response is a well-known regulatory network present in most bacteria and aimed at addressing DNA damage. It has also been linked extensively to stress-induced mutagenesis, virulence and the emergence and dissemination of antibiotic resistance determinants. Recently, the SOS response has been shown to regulate the activity of integrases in the chromosomal superintegrons of the Vibrionaceae, which encompasses a wide range of pathogenic species harboring multiple chromosomes. Here we combine in silico and in vitro techniques to perform a comparative genomics analysis of the SOS regulon in the Vibrionaceae, and we extend the methodology to map this transcriptional network in other bacterial species harboring multiple chromosomes. Results Our analysis provides the first comprehensive description of the SOS response in a family (Vibrionaceae that includes major human pathogens. It also identifies several previously unreported members of the SOS transcriptional network, including two proteins of unknown function. The analysis of the SOS response in other bacterial species with multiple chromosomes uncovers additional regulon members and reveals that there is a conserved core of SOS genes, and that specialized additions to this basic network take place in different phylogenetic groups. Our results also indicate that across all groups the main elements of the SOS response are always found in the large chromosome, whereas specialized additions are found in the smaller chromosomes and plasmids. Conclusions Our findings confirm that the SOS response of the Vibrionaceae is strongly linked with pathogenicity and dissemination of antibiotic resistance, and suggest that the characterization of the newly identified members of this regulon could provide key insights into the pathogenesis of Vibrio. The persistent location of key SOS genes in the large chromosome across several bacterial groups confirms that the SOS response plays an

Analysis of the SOS response of Vibrio and other bacteria with multiple chromosomes.

Science.gov (United States)

Sanchez-Alberola, Neus; Campoy, Susana; Barbé, Jordi; Erill, Ivan

2012-02-03

The SOS response is a well-known regulatory network present in most bacteria and aimed at addressing DNA damage. It has also been linked extensively to stress-induced mutagenesis, virulence and the emergence and dissemination of antibiotic resistance determinants. Recently, the SOS response has been shown to regulate the activity of integrases in the chromosomal superintegrons of the Vibrionaceae, which encompasses a wide range of pathogenic species harboring multiple chromosomes. Here we combine in silico and in vitro techniques to perform a comparative genomics analysis of the SOS regulon in the Vibrionaceae, and we extend the methodology to map this transcriptional network in other bacterial species harboring multiple chromosomes. Our analysis provides the first comprehensive description of the SOS response in a family (Vibrionaceae) that includes major human pathogens. It also identifies several previously unreported members of the SOS transcriptional network, including two proteins of unknown function. The analysis of the SOS response in other bacterial species with multiple chromosomes uncovers additional regulon members and reveals that there is a conserved core of SOS genes, and that specialized additions to this basic network take place in different phylogenetic groups. Our results also indicate that across all groups the main elements of the SOS response are always found in the large chromosome, whereas specialized additions are found in the smaller chromosomes and plasmids. Our findings confirm that the SOS response of the Vibrionaceae is strongly linked with pathogenicity and dissemination of antibiotic resistance, and suggest that the characterization of the newly identified members of this regulon could provide key insights into the pathogenesis of Vibrio. The persistent location of key SOS genes in the large chromosome across several bacterial groups confirms that the SOS response plays an essential role in these organisms and sheds light into the

Plant cultivars derived from mutation induction or the use of induced mutants in cross breeding

International Nuclear Information System (INIS)

Micke, A.; Maluszynski, M.; Donini, B.

1985-01-01

Since 1969 we have collected information on cultivated varieties of plants, developed by using induced mutations. Whenever we learn about a cultivar presumably derived from an induced mutant or from use of mutants in crosses. we mail a questionnaire to the breeder. The information gathered in this way is stored in our file on ''Mutant Varieties''. Excerpts are published regularly in the form of a list in the FAO/IAEA Mutation Breeding Newsletter. Our mutant variety list has repeatedly provided a basis for analyses on the value and prospects of mutation breeding

Plant cultivars derived from mutation induction or the use of induced mutants in cross breeding

Energy Technology Data Exchange (ETDEWEB)

Micke, A; Maluszynski, M; Donini, B [Joint FAO/IAEA Division, Plant Breeding and Genetics Section, Vienna (Austria)

1985-05-01

Since 1969 we have collected information on cultivated varieties of plants, developed by using induced mutations. Whenever we learn about a cultivar presumably derived from an induced mutant or from use of mutants in crosses. we mail a questionnaire to the breeder. The information gathered in this way is stored in our file on ''Mutant Varieties''. Excerpts are published regularly in the form of a list in the FAO/IAEA Mutation Breeding Newsletter. Our mutant variety list has repeatedly provided a basis for analyses on the value and prospects of mutation breeding.

Characteristics of mutant lines of sweet potato flour

International Nuclear Information System (INIS)

Aryanti

2012-01-01

Research on mutation induction of sweet potato Sari variety has been conducted. Flour mutant lines were obtained from selection of M1V5 tubers irradiated by gamma rays at the dose of 10 Gy. Flour was made by peeling of tubers, then dried, blended and sieved. The quality test of flour have been done by measuring degree of whiteness, proximate, amylose contents, water content, soluble water, swelling power, and flour characteristics. The result of this work showed that flour of C6.26.13 mutant line had higher protein content than the parent plant with concentration of 3.62 % and its amylose content was also higher than the other mutant lines. The soluble water value of mutant lines were significant different compared to the parent plant from 1.82 to 2.25 % and swelling power from 4.28 to 5.55 %. The flour granule of the mutant line was different compared to the parent plant. (author)

Construct Validity of the Societal Outreach Scale (SOS).

Science.gov (United States)

Fike, David S; Denton, Jason; Walk, Matt; Kish, Jennifer; Gorman, Ira

2018-04-01

The American Physical Therapy Association (APTA) has been working toward a vision of increasing professional focus on societal-level health. However, performance of social responsibility and related behaviors by physical therapists remain relatively poorly integrated into practice. Promoting a focus on societal outreach is necessary for all health care professionals to impact the health of their communities. The objective was to document the validity of the 14-item Societal Outreach Scale (SOS) for use with practicing physical therapists. This study used a cross-sectional survey. The SOS was transmitted via email to all therapists who were licensed and practicing in 10 states in the United States that were purposefully selected to assure a broad representation. A sample of 2612 usable responses was received. Factor analysis was applied to assess construct validity of the instrument. Of alternate models, a 3-factor model best demonstrated goodness of fit with the sample data according to conventional indices (standardized root mean squared residual = .03, comparative fit index .96, root mean square error of approximation = .06). The 3 factors measured by the SOS were labeled Societal-Level Health Advocacy, Community Engagement/Social Integration, and Political Engagement. Internal consistency reliability was 0.7 for all factors. The 3-factor SOS demonstrated acceptable validity and reliability. Though the sample included a broad representation of physical therapists, this was a single cross-sectional study. Additional confirmatory factor analysis, reliability testing, and word refinement of the tool are warranted. Given the construct validity and reliability of the 3-factor SOS, it is recommended for use as a validated instrument to measure physical therapists' performance of social responsibility and related behaviors.

A metabonomic evaluation of the monocrotaline-induced sinusoidal obstruction syndrome (SOS) in rats

International Nuclear Information System (INIS)

Conotte, R.; Colet, J.-M.

2014-01-01

The main curative treatment of colorectal cancer remains the surgery. However, when metastases are suspected, surgery is followed by a preventive chemotherapy using oxaliplatin which, unfortunately, may cause liver sinusoidal obstruction syndrome (SOS). Such hepatic damage is barely detected during or after chemotherapy due to a lack of effective diagnostic procedures, but liver biopsy. The primary objective of the present study was to identify potential early diagnosis biomarkers of SOS using a metabonomic approach. SOS was induced in rats by monocrotaline, a prototypical toxic substance. 1 H NMR spectroscopy analysis of urine samples collected from rats treated with monocrotaline showed significant metabolic changes as compared to controls. During a first phase, cellular protective mechanisms such as an increased synthesis of GSH (reduced taurine) and the recruitment of cell osmolytes in the liver (betaine) were seen. In the second phase, the disturbance of the urea cycle (increased ornithine and urea reduction) leading to the depletion of NO, the alteration in the GSH synthesis (increased creatine and GSH precursors (glutamate, dimethylglycine and sarcosine)), and the liver necrosis (decrease taurine and increase creatine) all indicate the development of SOS. - Highlights: • Urine metabonomic profiles of SOS have been identified. • Urine osmoprotectants and anti-oxidants indicated an initial liver protection. • Liver necrosis was demonstrated by increased urine levels of taurine and creatine. • NO depletion was suggested by changes in ornithine and urea

Bevacizumab exacerbates sinusoidal obstruction syndrome (SOS) in the animal model and increases MMP 9 production.

Science.gov (United States)

Jafari, Azin; Matthaei, Hanno; Wehner, Sven; Tonguc, Tolga; Kalff, Jörg C; Manekeller, Steffen

2018-04-24

Thanks to modern multimodal treatment the ouctome of patients with colorectal cancer has experienced significant improvements. As a downside, agent specific side effects have been observed such as sinusoidal obstruction syndrome (SOS) after oxaliplatin chemotherapy (OX). Bevazicumab targeting VEGF is nowadays comprehensively used in combination protocols with OX but its impact on hepatotoxicity is thus far elusive and focus of the present study. After MCT administration 67% of animals developed SOS. GOT serum concentration significantly increased in animals developing SOS ( p SOS. In contrast, animals receiving VEGF developed SOS merely in 40% while increasing the VEGF dose led to a further decrease in SOS development to 25%. MMP 9 concentration in animals developing SOS was significantly higher compared to controls ( p SOS paralleled by MMP 9 production. Therefore, OX-Bevacizumab combination therapies should be administered with caution, especially if liver parenchyma damage is apparent. Male Sprague-Dawley rats were gavaged Monocrotaline (MCT) to induce SOS. Recombinant VEGF or an Anti-VEGF antibody was administered to MCT-treated rats and the hepatotoxic effect monitored in defined time intervals. MMP 9 expression in the liver was measured by ELISA.

A flow cytometry-optimized assay using an SOS-green fluorescent protein (SOS-GFP) whole-cell biosensor for the detection of genotoxins in complex environments

DEFF Research Database (Denmark)

Norman, Anders; Hansen, Lars H.; Sørensen, Søren Johannes

2006-01-01

/mL, and proved far more sensitive than a previously published assay using the same biosensor strain. By applying the SOS-green fluorescent protein (GFP) whole-cell biosensor directly to soil microcosms we were also able to evaluate both the applicability and sensitivity of a biosensor based on SOS...

Sequence analysis of the Ras-MAPK pathway genes SOS1, EGFR & GRB2 in silver foxes (Vulpes vulpes): candidate genes for hereditary hyperplastic gingivitis.

Science.gov (United States)

Clark, Jo-Anna B J; Tully, Sara J; Dawn Marshall, H

2014-12-01

Hereditary hyperplastic gingivitis (HHG) is an autosomal recessive disease that presents with progressive gingival proliferation in farmed silver foxes. Hereditary gingival fibromatosis (HGF) is an analogous condition in humans that is genetically heterogeneous with several known autosomal dominant loci. For one locus the causative mutation is in the Son of sevenless homologue 1 (SOS1) gene. For the remaining loci, the molecular mechanisms are unknown but Ras pathway involvement is suspected. Here we compare sequences for the SOS1 gene, and two adjacent genes in the Ras pathway, growth receptor bound protein 2 (GRB2) and epidermal growth factor receptor (EGFR), between HHG-affected and unaffected foxes. We conclude that the known HGF causative mutation does not cause HHG in foxes, nor do the coding regions or intron-exon boundaries of these three genes contain any candidate mutations for fox gum disease. Patterns of molecular evolution among foxes and other mammals reflect high conservation and strong functional constraints for SOS1 and GRB2 but reveal a lineage-specific pattern of variability in EGFR consistent with mutational rate differences, relaxed functional constraints, and possibly positive selection.

Molecular kinetics. Ras activation by SOS: allosteric regulation by altered fluctuation dynamics.

Science.gov (United States)

Iversen, Lars; Tu, Hsiung-Lin; Lin, Wan-Chen; Christensen, Sune M; Abel, Steven M; Iwig, Jeff; Wu, Hung-Jen; Gureasko, Jodi; Rhodes, Christopher; Petit, Rebecca S; Hansen, Scott D; Thill, Peter; Yu, Cheng-Han; Stamou, Dimitrios; Chakraborty, Arup K; Kuriyan, John; Groves, Jay T

2014-07-04

Activation of the small guanosine triphosphatase H-Ras by the exchange factor Son of Sevenless (SOS) is an important hub for signal transduction. Multiple layers of regulation, through protein and membrane interactions, govern activity of SOS. We characterized the specific activity of individual SOS molecules catalyzing nucleotide exchange in H-Ras. Single-molecule kinetic traces revealed that SOS samples a broad distribution of turnover rates through stochastic fluctuations between distinct, long-lived (more than 100 seconds), functional states. The expected allosteric activation of SOS by Ras-guanosine triphosphate (GTP) was conspicuously absent in the mean rate. However, fluctuations into highly active states were modulated by Ras-GTP. This reveals a mechanism in which functional output may be determined by the dynamical spectrum of rates sampled by a small number of enzymes, rather than the ensemble average. Copyright © 2014, American Association for the Advancement of Science.

Evaluation on selected dwarf and semidwarf mutants of upland rice

International Nuclear Information System (INIS)

Riyanti Sumanggono, A.M.

1984-01-01

Seratus malam local upland rice variety was irradiated with gamma-rays at doses of O.1, 0.2, 0.3, 0.4 and 0.5 kGy. Observation of radiation effect was carried out on root and shoot length of M 1 seedlings; plant height, panicle length and number of tiller and seed sterility in M 1 plants. Selection for dwarf and semi-dwarf characteristics were done in M 2 plants, and selected again in M 3 . Observation on radiation effect indicated that 'Seratus Malam' seems to be more resistant than the lowland rice varieties. Increasing doses of radiation caused increasing frequency of chlorophyll mutations as well as chlorophyll mutants. Whereas, selection of dwarf or semi-dwarf in M 2 plants seems that mutant and mutation frequencies decreased as the dose increased. Dose of 0.2 kGy was suitable for selection of dwarf or semi-dwarf plants. Plant height could be influenced by environmental condition. Many of the selected M 2 plants were not really dwarf or semi-dwarf mutants. M 3 evaluation of the selected M 2 plants was really beneficial in the mutant selection. (author)

Simulation of Fungal-Mediated Cell Death by Fumonisin B1 and Selection of Fumonisin B1–Resistant (fbr) Arabidopsis Mutants

Science.gov (United States)

Stone, Julie M.; Heard, Jacqueline E.; Asai, Tsuneaki; Ausubel, Frederick M.

2000-01-01

Fumonisin B1 (FB1), a programmed cell death–eliciting toxin produced by the necrotrophic fungal plant pathogen Fusarium moniliforme, was used to simulate pathogen infection in Arabidopsis. Plants infiltrated with 10 μM FB1 and seedlings transferred to agar media containing 1 μM FB1 develop lesions reminiscent of the hypersensitive response, including generation of reactive oxygen intermediates, deposition of phenolic compounds and callose, accumulation of phytoalexin, and expression of pathogenesis-related (PR) genes. Arabidopsis FB1-resistant (fbr) mutants were selected directly by sowing seeds on agar containing 1 μM FB1, on which wild-type seedlings fail to develop. Two mutants chosen for further analyses, fbr1 and fbr2, had altered PR gene expression in response to FB1. fbr1 and fbr2 do not exhibit differential resistance to the avirulent bacterial pathogen Pseudomonas syringae pv maculicola (ES4326) expressing the avirulence gene avrRpt2 but do display enhanced resistance to a virulent isogenic strain that lacks the avirulence gene. Our results demonstrate the utility of FB1 for high-throughput isolation of Arabidopsis defense-related mutants and suggest that pathogen-elicited programmed cell death of host cells may be an important feature of compatible plant–pathogen interactions. PMID:11041878

Genotoxicity risk assessment of diversely substituted quinolines using the SOS chromotest.

Science.gov (United States)

Duran, Leidy Tatiana Díaz; Rincón, Nathalia Olivar; Galvis, Carlos Eduardo Puerto; Kouznetsov, Vladimir V; Lorenzo, Jorge Luis Fuentes

2015-03-01

Quinolines are aromatic nitrogen compounds with wide therapeutic potential to treat parasitic and microbial diseases. In this study, the genotoxicity of quinoline, 4-methylquinoline, 4-nitroquinoline-1-oxide (4-NQO), and diversely functionalized quinoline derivatives and the influence of the substituents (functional groups and/or atoms) on their genotoxicity were tested using the SOS chromotest. Quinoline derivatives that induce genotoxicity by the formation of an enamine epoxide structure did not induce the SOS response in Escherichia coli PQ37 cells, with the exception of 4-methylquinoline that was weakly genotoxic. The chemical nature of the substitution (C-5 to C-8: hydroxyl, nitro, methyl, isopropyl, chlorine, fluorine, and iodine atoms; C-2: phenyl and 3,4-methylenedioxyphenyl rings) of quinoline skeleton did not significantly modify compound genotoxicities; however, C-2 substitution with α-, β-, or γ-pyridinyl groups removed 4-methylquinoline genotoxicity. On the other hand, 4-NQO derivatives whose genotoxic mechanism involves reduction of the C-4 nitro group were strong inducers of the SOS response. Methyl and nitrophenyl substituents at C-2 of 4-NQO core affected the genotoxic potency of this molecule. The relevance of these results is discussed in relation to the potential use of the substituted quinolines. The work showed the sensitivity of SOS chromotest for studying structure-genotoxicity relationships and bioassay-guided quinoline synthesis. © 2013 Wiley Periodicals, Inc.

Zinc blocks SOS-induced antibiotic resistance via inhibition of RecA in Escherichia coli.

Science.gov (United States)

Bunnell, Bryan E; Escobar, Jillian F; Bair, Kirsten L; Sutton, Mark D; Crane, John K

2017-01-01

Zinc inhibits the virulence of diarrheagenic E. coli by inducing the envelope stress response and inhibiting the SOS response. The SOS response is triggered by damage to bacterial DNA. In Shiga-toxigenic E. coli, the SOS response strongly induces the production of Shiga toxins (Stx) and of the bacteriophages that encode the Stx genes. In E. coli, induction of the SOS response is accompanied by a higher mutation rate, called the mutator response, caused by a shift to error-prone DNA polymerases when DNA damage is too severe to be repaired by canonical DNA polymerases. Since zinc inhibited the other aspects of the SOS response, we hypothesized that zinc would also inhibit the mutator response, also known as hypermutation. We explored various different experimental paradigms to induce hypermutation triggered by the SOS response, and found that hypermutation was induced not just by classical inducers such as mitomycin C and the quinolone antibiotics, but also by antiviral drugs such as zidovudine and anti-cancer drugs such as 5-fluorouracil, 6-mercaptopurine, and azacytidine. Zinc salts inhibited the SOS response and the hypermutator phenomenon in E. coli as well as in Klebsiella pneumoniae, and was more effective in inhibiting the SOS response than other metals. We then attempted to determine the mechanism by which zinc, applied externally in the medium, inhibits hypermutation. Our results show that zinc interferes with the actions of RecA, and protects LexA from RecA-mediated cleavage, an early step in initiation of the SOS response. The SOS response may play a role in the development of antibiotic resistance and the effect of zinc suggests ways to prevent it.

Zinc blocks SOS-induced antibiotic resistance via inhibition of RecA in Escherichia coli.

Directory of Open Access Journals (Sweden)

Bryan E Bunnell

Full Text Available Zinc inhibits the virulence of diarrheagenic E. coli by inducing the envelope stress response and inhibiting the SOS response. The SOS response is triggered by damage to bacterial DNA. In Shiga-toxigenic E. coli, the SOS response strongly induces the production of Shiga toxins (Stx and of the bacteriophages that encode the Stx genes. In E. coli, induction of the SOS response is accompanied by a higher mutation rate, called the mutator response, caused by a shift to error-prone DNA polymerases when DNA damage is too severe to be repaired by canonical DNA polymerases. Since zinc inhibited the other aspects of the SOS response, we hypothesized that zinc would also inhibit the mutator response, also known as hypermutation. We explored various different experimental paradigms to induce hypermutation triggered by the SOS response, and found that hypermutation was induced not just by classical inducers such as mitomycin C and the quinolone antibiotics, but also by antiviral drugs such as zidovudine and anti-cancer drugs such as 5-fluorouracil, 6-mercaptopurine, and azacytidine. Zinc salts inhibited the SOS response and the hypermutator phenomenon in E. coli as well as in Klebsiella pneumoniae, and was more effective in inhibiting the SOS response than other metals. We then attempted to determine the mechanism by which zinc, applied externally in the medium, inhibits hypermutation. Our results show that zinc interferes with the actions of RecA, and protects LexA from RecA-mediated cleavage, an early step in initiation of the SOS response. The SOS response may play a role in the development of antibiotic resistance and the effect of zinc suggests ways to prevent it.

SOS1 and PTPN11 mutations in five cases of Noonan syndrome with multiple giant cell lesions.

Science.gov (United States)

Beneteau, Claire; Cavé, Hélène; Moncla, Anne; Dorison, Nathalie; Munnich, Arnold; Verloes, Alain; Leheup, Bruno

2009-10-01

We report five cases of multiple giant cell lesions in patients with typical Noonan syndrome. Such association has frequently been referred to as Noonan-like/multiple giant cell (NL/MGCL) syndrome before the molecular definition of Noonan syndrome. Two patients show mutations in PTPN11 (p.Tyr62Asp and p.Asn308Asp) and three in SOS1 (p.Arg552Ser and p.Arg552Thr). The latter are the first SOS1 mutations reported outside PTPN11 in NL/MGCL syndrome. MGCL lesions were observed in jaws ('cherubism') and joints ('pigmented villonodular synovitis'). We show through those patients that both types of MGCL are not PTPN11-specific, but rather represent a low penetrant (or perhaps overlooked) complication of the dysregulated RAS/MAPK signaling pathway. We recommend discarding NL/MGCL syndrome from the nosology, as this presentation is neither gene-nor allele-specific of Noonan syndrome; these patients should be described as Noonan syndrome with MGCL (of the mandible, the long bone...). The term cherubism should be used only when multiple giant cell lesions occur without any other clinical and molecular evidence of Noonan syndrome, with or without mutations of the SH3BP2 gene.

Congruence for SOS with data

NARCIS (Netherlands)

Mousavi, M.R.; Reniers, M.A.; Groote, J.F.

2004-01-01

Abstract While studying the specification of the operational semantics of different programming languages and formalisms, one can observe the following three facts. Firstly, Plotkin¿s style of Structured Operational Semantics (SOS) has become a standard in defining operational semantics. Secondly,

Dynamic studies of H-Ras•GTPγS interactions with nucleotide exchange factor Sos reveal a transient ternary complex formation in solution.

Science.gov (United States)

Vo, Uybach; Vajpai, Navratna; Embrey, Kevin J; Golovanov, Alexander P

2016-07-14

The cycling between GDP- and GTP- bound forms of the Ras protein is partly regulated by the binding of Sos. The structural/dynamic behavior of the complex formed between activated Sos and Ras at the point of the functional cycle where the nucleotide exchange is completed has not been described to date. Here we show that solution NMR spectra of H-Ras∙GTPγS mixed with a functional fragment of Sos (Sos(Cat)) at a 2:1 ratio are consistent with the formation of a rather dynamic assembly. H-Ras∙GTPγS binding was in fast exchange on the NMR timescale and retained a significant degree of molecular tumbling independent of Sos(Cat), while Sos(Cat) also tumbled largely independently of H-Ras. Estimates of apparent molecular weight from both NMR data and SEC-MALS revealed that, at most, only one H-Ras∙GTPγS molecule appears stably bound to Sos. The weak transient interaction between Sos and the second H-Ras∙GTPγS may provide a necessary mechanism for complex dissociation upon the completion of the native GDP → GTP exchange reaction, but also explains measurable GTP → GTP exchange activity of Sos routinely observed in in vitro assays that use fluorescently-labelled analogs of GTP. Overall, the data presents the first dynamic snapshot of Ras functional cycle as controlled by Sos.

[SOS response of DNA repair and genetic cell instability under hypoxic conditions].

Science.gov (United States)

Vasil'eva, S V; Strel'tsova, D A

2011-01-01

The SOS DNA repair pathway is induced in E. coli as a multifunctional cell response to a wide variety of signals: UV, X or gamma-irradiation, mitomycin C or nalidixic acid treatment, thymine starvation, etc. Triggering of the system can be used as a general and early sign of DNA damage. Additionally, the SOS-response is known to be an "error-prone" DNA repair pathway and one of the sources of genetic instability. Hypoxic conditions are established to be the major factor of genetic instability as well. In this paper we for the first time studied the SOS DNA repair response under hypoxic conditions induced by the well known aerobic SOS-inducers. The SOS DNA repair response was examined as a reaction of E. coli PQ37 [sfiA::lacZ] cells to UVC, NO-donating agents and 4NQO. Here we provide evidence that those agents were able to induce the SOS DNA repair response in E. coli at anaerobic growth conditions. The process does not depend on the transcriptional activity of the universal protein of E. col anaerobic growth Fnr [4Fe-4S]2+ or can not be referred to as an indicator of genetic instability in hypoxic conditions.

A metabonomic evaluation of the monocrotaline-induced sinusoidal obstruction syndrome (SOS) in rats

Energy Technology Data Exchange (ETDEWEB)

Conotte, R.; Colet, J.-M., E-mail: jean-marie.colet@umons.ac.be

2014-04-15

The main curative treatment of colorectal cancer remains the surgery. However, when metastases are suspected, surgery is followed by a preventive chemotherapy using oxaliplatin which, unfortunately, may cause liver sinusoidal obstruction syndrome (SOS). Such hepatic damage is barely detected during or after chemotherapy due to a lack of effective diagnostic procedures, but liver biopsy. The primary objective of the present study was to identify potential early diagnosis biomarkers of SOS using a metabonomic approach. SOS was induced in rats by monocrotaline, a prototypical toxic substance. {sup 1}H NMR spectroscopy analysis of urine samples collected from rats treated with monocrotaline showed significant metabolic changes as compared to controls. During a first phase, cellular protective mechanisms such as an increased synthesis of GSH (reduced taurine) and the recruitment of cell osmolytes in the liver (betaine) were seen. In the second phase, the disturbance of the urea cycle (increased ornithine and urea reduction) leading to the depletion of NO, the alteration in the GSH synthesis (increased creatine and GSH precursors (glutamate, dimethylglycine and sarcosine)), and the liver necrosis (decrease taurine and increase creatine) all indicate the development of SOS. - Highlights: • Urine metabonomic profiles of SOS have been identified. • Urine osmoprotectants and anti-oxidants indicated an initial liver protection. • Liver necrosis was demonstrated by increased urine levels of taurine and creatine. • NO depletion was suggested by changes in ornithine and urea.

The Arabidopsis mutant cev1 has constitutively active jasmonate and ethylene signal pathways and enhanced resistance to pathogens.

Science.gov (United States)

Ellis, C; Turner, J G

2001-05-01

Jasmonates (JAs) inhibit plant growth and induce plant defense responses. To define genes in the Arabidopsis JA signal pathway, we screened for mutants with constitutive expression of a luciferase reporter for the JA-responsive promoter from the vegetative storage protein gene VSP1. One mutant, named constitutive expression of VSP1 (cev1), produced plants that were smaller than wild type, had stunted roots with long root hairs, accumulated anthocyanin, had constitutive expression of the defense-related genes VSP1, VSP2, Thi2.1, PDF1.2, and CHI-B, and had enhanced resistance to powdery mildew diseases. Genetic evidence indicated that the cev1 phenotype required both COI1, an essential component of the JA signal pathway, and ETR1, which encodes the ethylene receptor. We conclude that cev1 stimulates both the JA and the ethylene signal pathways and that CEV1 regulates an early step in an Arabidopsis defense pathway.

Refined functional relations for the elliptic SOS model

Energy Technology Data Exchange (ETDEWEB)

Galleas, W., E-mail: w.galleas@uu.nl [ARC Centre of Excellence for the Mathematics and Statistics of Complex Systems, University of Melbourne, VIC 3010 (Australia)

2013-02-21

In this work we refine the method presented in Galleas (2012) [1] and obtain a novel kind of functional equation determining the partition function of the elliptic SOS model with domain wall boundaries. This functional relation arises from the dynamical Yang-Baxter relation and its solution is given in terms of multiple contour integrals.

Refined functional relations for the elliptic SOS model

International Nuclear Information System (INIS)

Galleas, W.

2013-01-01

In this work we refine the method presented in Galleas (2012) [1] and obtain a novel kind of functional equation determining the partition function of the elliptic SOS model with domain wall boundaries. This functional relation arises from the dynamical Yang–Baxter relation and its solution is given in terms of multiple contour integrals.

The Arabidopsis cax1 mutant exhibits impaired ion homeostasis, development, and hormonal responses and reveals interplay among vacuolar transporters.

Science.gov (United States)

Cheng, Ning-Hui; Pittman, Jon K; Barkla, Bronwyn J; Shigaki, Toshiro; Hirschi, Kendal D

2003-02-01

The Arabidopsis Ca(2+)/H(+) transporter CAX1 (Cation Exchanger1) may be an important regulator of intracellular Ca(2+) levels. Here, we describe the preliminary localization of CAX1 to the tonoplast and the molecular and biochemical characterization of cax1 mutants. We show that these mutants exhibit a 50% reduction in tonoplast Ca(2+)/H(+) antiport activity, a 40% reduction in tonoplast V-type H(+)-translocating ATPase activity, a 36% increase in tonoplast Ca(2+)-ATPase activity, and increased expression of the putative vacuolar Ca(2+)/H(+) antiporters CAX3 and CAX4. Enhanced growth was displayed by the cax1 lines under Mn(2+) and Mg(2+) stress conditions. The mutants exhibited altered plant development, perturbed hormone sensitivities, and altered expression of an auxin-regulated promoter-reporter gene fusion. We propose that CAX1 regulates myriad plant processes and discuss the observed phenotypes with regard to the compensatory alterations in other transporters.

The Arabidopsis cax1 Mutant Exhibits Impaired Ion Homeostasis, Development, and Hormonal Responses and Reveals Interplay among Vacuolar Transporters

Science.gov (United States)

Cheng, Ning-Hui; Pittman, Jon K.; Barkla, Bronwyn J.; Shigaki, Toshiro; Hirschi, Kendal D.

2003-01-01

The Arabidopsis Ca2+/H+ transporter CAX1 (Cation Exchanger1) may be an important regulator of intracellular Ca2+ levels. Here, we describe the preliminary localization of CAX1 to the tonoplast and the molecular and biochemical characterization of cax1 mutants. We show that these mutants exhibit a 50% reduction in tonoplast Ca2+/H+ antiport activity, a 40% reduction in tonoplast V-type H+-translocating ATPase activity, a 36% increase in tonoplast Ca2+-ATPase activity, and increased expression of the putative vacuolar Ca2+/H+ antiporters CAX3 and CAX4. Enhanced growth was displayed by the cax1 lines under Mn2+ and Mg2+ stress conditions. The mutants exhibited altered plant development, perturbed hormone sensitivities, and altered expression of an auxin-regulated promoter-reporter gene fusion. We propose that CAX1 regulates myriad plant processes and discuss the observed phenotypes with regard to the compensatory alterations in other transporters. PMID:12566577

The Voltage-Dependent Anion Channel 1 (AtVDAC1 Negatively Regulates Plant Cold Responses during Germination and Seedling Development in Arabidopsis and Interacts with Calcium Sensor CBL1

Directory of Open Access Journals (Sweden)

Zhi-Yong Li

2013-01-01

Full Text Available The voltage-dependent anion channel (VDAC, a highly conserved major mitochondrial outer membrane protein, plays crucial roles in energy metabolism and metabolite transport. However, knowledge about the roles of the VDAC family in plants is limited. In this study, we investigated the expression pattern of VDAC1 in Arabidopsis and found that cold stress promoted the accumulation of VDAC1 transcripts in imbibed seeds and mature plants. Overexpression of VDAC1 reduced tolerance to cold stress in Arabidopsis. Phenotype analysis of VDAC1 T-DNA insertion mutant plants indicated that a vdac1 mutant line had faster germination kinetics under cold treatment and showed enhanced tolerance to freezing. The yeast two-hybrid system revealed that VDAC1 interacts with CBL1, a calcium sensor in plants. Like the vdac1, a cbl1 mutant also exhibited a higher seed germination rate. We conclude that both VDAC1 and CBL1 regulate cold stress responses during seed germination and plant development.

Radiation-hardened CMOS/SOS LSI circuits

International Nuclear Information System (INIS)

Aubuchon, K.G.; Peterson, H.T.; Shumake, D.P.

1976-01-01

The recently developed technology for building radiation-hardened CMOS/SOS devices has now been applied to the fabrication of LSI circuits. This paper describes and presents results on three different circuits: an 8-bit adder/subtractor (Al gate), a 256-bit shift register (Si gate), and a polycode generator (Al gate). The 256-bit shift register shows very little degradation after 1 x 10 6 rads (Si), with an increase from 1.9V to 2.9V in minimum operating voltage, a decrease of about 20% in maximum frequency, and little or no change in quiescent current. The p-channel thresholds increase from -0.9V to -1.3V, while the n-channel thresholds decrease from 1.05 to 0.23V, and the n-channel leakage remains below 1nA/mil. Excellent hardening results were also obtained on the polycode generator circuit. Ten circuits were irradiated to 1 x 10 6 rads (Si), and all continued to function well, with an increase in minimum power supply voltage from 2.85V to 5.85V and an increase in quiescent current by a factor of about 2. Similar hardening results were obtained on the 8-bit adder, with the minimum power supply voltage increasing from 2.2V to 4.6V and the add time increasing from 270 to 350 nsec after 1 x 10 6 rads (Si). These results show that large CMOS/SOS circuits can be hardened to above 1 x 10 6 rads (Si) with either the Si gate or Al gate technology. The paper also discusses the relative advantages of the Si gate versus the Al gate technology

In vitro evaluering van die effektiwiteit van vyf plante wat tradisioneel teen seksueel oordraagbare siektes gebruik word

Directory of Open Access Journals (Sweden)

H. Swart

2002-09-01

Full Text Available Tot soveel as 60% van die Suid-Afrikaanse bevolking raadpleeg tradisionele genesers vir siektetoestande, insluitende seksueel oordraagbare siektes (SOS. Medisinale plante speel ’n belangrike rol in die behandeling van SOS deur tradisionele genesers, maar sonder enige wetenskaplike bewyse van effektiwiteit. Vir hierdie studie is 5 plante vanuit die literatuur gekies op grond van hul gebruik deur tradisionele genesers vir die behandeling van SOS. Siftingstoetse vir die bepaling van aktiwiteit teen bakterieë en teen SOS is op die plante uitgevoer. Die plante was Clematis brachiata, Elephantorrhiza elephantina, Lepidium bonariense, Ranunculus multifidus en Typha capensis. Siftingstoetse is uitgevoer met die organismes Candida albicans, Neisseria gonorrhoeae en Haemophilus ducreyi wat met SOS geassosieer word, terwyl Bacillus subtilus, Micrococcus luteus, Staphylococcus aureus, Enterobacter sp., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa en Aspergillus niger ook in die siftingstoetse ingesluit is. Slegs Lepidium bonariense het aktiwiteit teen die gebruikte organismes getoon. Dit is dus duidelik dat daar ’n behoefte bestaan om die effektiwiteit van medisinale plante wetenskaplik te bepaal en te kommunikeer.

Characterization of the SOS meta-regulon in the human gut microbiome.

Science.gov (United States)

Cornish, Joseph P; Sanchez-Alberola, Neus; O'Neill, Patrick K; O'Keefe, Ronald; Gheba, Jameel; Erill, Ivan

2014-05-01

Data from metagenomics projects remain largely untapped for the analysis of transcriptional regulatory networks. Here, we provide proof-of-concept that metagenomic data can be effectively leveraged to analyze regulatory networks by characterizing the SOS meta-regulon in the human gut microbiome. We combine well-established in silico and in vitro techniques to mine the human gut microbiome data and determine the relative composition of the SOS network in a natural setting. Our analysis highlights the importance of translesion synthesis as a primary function of the SOS response. We predict the association of this network with three novel protein clusters involved in cell wall biogenesis, chromosome partitioning and restriction modification, and we confirm binding of the SOS response transcriptional repressor to sites in the promoter of a cell wall biogenesis enzyme, a phage integrase and a death-on-curing protein. We discuss the implications of these findings and the potential for this approach for metagenome analysis.

Mutation induction and evaluation of high yield rice mutants

International Nuclear Information System (INIS)

Abdul Rahim Harun; Sobri Husein; Rusli Ibrahim

2006-01-01

The successful use of plant breeding for improving crops requires the existence of genetic variation of useful traits. Unfortunately, the desired variation is often lacking. However, radiation has been used to induce mutations and thereby generate genetic variation from which desired mutants may be selected. Mutation induction has become a proven way of creating variation within a crop variety. It offers the possibility of inducing desired attributes that either cannot be expressed in nature or have been lost during evolution. Rice is security food crop in Malaysia. Efforts were undertaken to enhance rice yield from 4.0 tones per hectare in 1995 to 5.5 tones per hectare in 2010. Proper management and good varieties are two factors that require for enhancing yield of rice. In this research, purified seeds of MR211 and MR219 were gamma irradiated at 100 to 400 Gray and sown for planting as M1 generation at MARDI experimental plot. The M2 population was sown in bulk with population size around 15,000 to 20,000 plants. Individual plant selection was carried out at maturity and each selected plant became a mutant line of M3 generation. Agronomic trial of M3 mutants lines were conducted in Mardi, Tanjung Karang, Selangor. About 115 of selected mutant lines were evaluated. Each row of those mutant lines were planted in two rows at planting distance of 25cm within and between rows. These mutant lines were visually observed and data were recorded in each of every mutant line. (Author)

CMOS/SOS 4k Rams hardened to 100 Krads (s:)

International Nuclear Information System (INIS)

Napoli, L.S.; Heagerty, W.F.; Smeltzer, R.K.; Yeh, J.L.

1982-01-01

Two CMOS/SOS 4K memories were fabricated with a recently developed, hardened SOS process. Memory functionality after radiation doses well in excess of 100 Krads(Si) was demonstrated. The critical device processing steps were identified. The radiationinduced failure mode of the memories is understood in terms of the circuit organization and the radiation behavior of the individual transistors in the memories

Characterization and fine mapping of a light-dependent leaf lesion mimic mutant 1 in rice.

Science.gov (United States)

Wang, Jing; Ye, Bangquan; Yin, Junjie; Yuan, Can; Zhou, Xiaogang; Li, Weitao; He, Min; Wang, Jichun; Chen, Weilan; Qin, Peng; Ma, Bintian; Wang, Yuping; Li, Shigui; Chen, Xuewei

2015-12-01

Plants that spontaneously produce lesion mimics or spots, without any signs of obvious adversity, such as pesticide and mechanical damage, or pathogen infection, are so-called lesion mimic mutants (lmms). In rice, many lmms exhibit enhanced resistance to pathogens, which provides a unique opportunity to uncover the molecular mechanism underlying lmms. We isolated a rice light-dependent leaf lesion mimic mutant 1 (llm1). Lesion spots appeared in the leaves of the llm1 mutant at the tillering stage. Furthermore, the mutant llm1 had similar agronomic traits to wild type rice. Trypan blue and diamiobenzidine staining analyses revealed that the lesion spot formation on the llm1 mutant was due to programmed cell death and reactive oxygen species. The chloroplasts were severely damaged in the llm1 mutant, suggesting that chloroplast damage was associated with the formation of lesion spots in llm1. More importantly, llm1 exhibited enhanced resistance to bacterial blight pathogens within increased expression of pathogenesis related genes (PRs). Using a map-based cloning approach, we delimited the LLM1 locus to a 121-kb interval between two simple sequence repeat markers, RM17470 and RM17473, on chromosome 4. We sequenced the candidate genes on the interval and found that a base mutation had substituted adenine phosphate for thymine in the last exon of LOC_Os04g52130, which led to an amino acid change (Asp(388) to Val) in the llm1 mutant. Our investigation showed that the putative coproporphyrinogen III oxidase (CPOX) encoded by LOC_Os04g52130 was produced by LLM1 and that amino acid Asp(388) was essential for CPOX function. Our study provides the basis for further investigations into the mechanism underlying lesion mimic initiation associated with LLM1. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

First evidence on the validity and reliability of the Safety Organizing Scale-Nursing Home version (SOS-NH).

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Ausserhofer, Dietmar; Anderson, Ruth A; Colón-Emeric, Cathleen; Schwendimann, René

2013-08-01

The Safety Organizing Scale is a valid and reliable measure on safety behaviors and practices in hospitals. This study aimed to explore the psychometric properties of the Safety Organizing Scale-Nursing Home version (SOS-NH). In a cross-sectional analysis of staff survey data, we examined validity and reliability of the 9-item Safety SOS-NH using American Educational Research Association guidelines. This substudy of a larger trial used baseline survey data collected from staff members (n = 627) in a variety of work roles in 13 nursing homes (NHs) in North Carolina and Virginia. Psychometric evaluation of the SOS-NH revealed good response patterns with low average of missing values across all items (3.05%). Analyses of the SOS-NH's internal structure (eg, comparative fit indices = 0.929, standardized root mean square error of approximation = 0.045) and consistency (composite reliability = 0.94) suggested its 1-dimensionality. Significant between-facility variability, intraclass correlations, within-group agreement, and design effect confirmed appropriateness of the SOS-NH for measurement at the NH level, justifying data aggregation. The SOS-NH showed discriminate validity from one related concept: communication openness. Initial evidence regarding validity and reliability of the SOS-NH supports its utility in measuring safety behaviors and practices among a wide range of NH staff members, including those with low literacy. Further psychometric evaluation should focus on testing concurrent and criterion validity, using resident outcome measures (eg, patient fall rates). Copyright © 2013 American Medical Directors Association, Inc. All rights reserved.

DNA repair in Haemophilus influenzae: isolation and characterization of an ultraviolet sensitive mutator mutant

International Nuclear Information System (INIS)

Walter, R.B.

1985-01-01

DNA repair in Haemophilus influenzae appears to be quite different from that seen in Escherichia coli in that H. influenzae shows neither SOS nor adaptation phenomena. Repair of DNA lesions in H. influenzae has been seen to occur via recombinational, excision, and mismatch repair pathways acting independently of one another. The author has isolated an ultraviolet (UV)-sensitive mutator mutant (mutB1) of H. influenzae Rd which shows deficiencies in both recombinational and mismatch repair pathways. This mutant is sensitive to a variety of DNA damaging agents as well as being hypermutable by alkylating agents and base analogues. MutB1 cells do not show post-UV DNA breakdown but do begin excision after UV irradiation. Genetic transformation with UV-irradiated DNA on mut B1 recipients shows that high (HE) and low (LE) efficiency markers are transformed at a ratio of 1.0 as in the mismatch repair deficient hex 1 mutant; however, kinetics of UV-inactivation experiments indicate that HE markers are sensitized and act as LE markers do on wild type recipients. Thus, the mutB gene product appears to play a role in both DNA repair and genetic transformation. A model is outlined which presents a role for a DNA helicase in both DNA repair and genetic transformation of H. influenzae

Evaluation of effects of busulfan and DMA on SOS in pediatric stem cell recipients.

Science.gov (United States)

Kerl, Kornelius; Diestelhorst, Christian; Bartelink, Imke; Boelens, Jaap; Trame, Mirjam N; Boos, Joachim; Hempel, Georg

2014-02-01

Busulfan (Bu) is a DNA-alkylating agent used for myeloablative conditioning in stem cell transplantation in children and adults. While the use of intravenous rather than oral administration of Bu has reduced inter-individual variability in plasma levels, toxicity still occurs frequently after hematopoietic stem cell transplantation (HSCT). Toxicity (especially hepatotoxic effects) of intravenous (IV) Bu may be related to both Bu and/or N,N-dimethylacetamide (DMA), the solvent of Bu. In this study, we assessed the relation between the exposure of Bu and DMA with regards to the clinical outcome in children from two cohorts. In a two-centre study Bu and DMA AUC (area under the curve) were correlated in pediatric stem cell recipients to the risk of developing SOS and to the clinical outcome. In patients receiving Bu four times per day Bu levels >1,500 µmol/L minute correlate to an increased risk of developing a SOS. In the collective cohort, summarizing data of all 53 patients of this study, neither high area under the curve (AUC) of Bu nor high AUC of DMA appears to be an independent risk factor for the development of SOS in children. In this study neither Bu nor DMA was observed as an independent risk factor for the development of SOS. To identify subgroups (e.g., infants), in which Bu or DMA might be risk factors for the induction of SOS, larger cohorts have to be evaluated. © 2013 Wiley Periodicals, Inc.

Sinusoidal obstruction syndrome (SOS): A light and electron microscopy study in human liver.

Science.gov (United States)

Vreuls, C P H; Driessen, A; Olde Damink, S W M; Koek, G H; Duimel, H; van den Broek, M A J; Dejong, C H C; Braet, F; Wisse, E

2016-05-01

Oxaliplatin is an important chemotherapeutic agent, used in the treatment of hepatic colorectal metastases, and known to induce the sinusoidal obstruction syndrome (SOS). Pathophysiological knowledge concerning SOS is based on a rat model. Therefore, the aim was to perform a comprehensive study of the features of human SOS, using both light microscopy (LM) and electron microscopy (EM). Included were all patients of whom wedge liver biopsies were collected during a partial hepatectomy for colorectal liver metastases, in a 4-year period. The wedge biopsy were perfusion fixated and processed for LM and EM. The SOS lesions were selected by LM and details were studied using EM. Material was available of 30 patients, of whom 28 patients received neo-adjuvant oxaliplatin. Eighteen (64%) of the 28 patients showed SOS lesions, based on microscopy. The lesions consisted of sinusoidal endothelial cell detachment from the space of Disse on EM. In the enlarged space of Disse a variable amount of erythrocytes were located. Sinusoidal endothelial cell detachment was present in human SOS, accompanied by enlargement of the space of Disse and erythrocytes in this area. These findings, originally described in a rat model, were now for the first time confirmed in human livers under clinically relevant settings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Agronomic characters and lodging resistance of plant height mutants of rice

International Nuclear Information System (INIS)

Zhang Zhonggui; Wu Yuejin; Liu Binmei; Xu Xue; Zhang Lili; Wang Min

2010-01-01

Fourteen plant height mutants of Nipponbare were used to study the effect of plant height on the agronomic characters and lodging resistance. The results indicated that the plant height was positively correlated with spike length, third internode length, height of gravity center, fresh weight of main stem, dry weight of main stem, thousand-grain weight, grain-yield per plant and biological yield, and the second internode length. Meanwhile, plant height played an important role in lodging resistance, it was significantly positively correlated with lodging index and negatively correlated with bending moment and culm type index. The correlation between agronomic characters and lodging resistance showed that several agronomic characters had strong impact on the lodging resistance, such as spike length, height of gravity center, basal internode length ( first and second internode), fresh and dry weight of main stem, dry weight of basal internode, seed setting, thousand-grain weight, grain-weight per plant and biological yield. (authors)

Isolation of New Gravitropic Mutants under Hypergravity Conditions.

Science.gov (United States)

Mori, Akiko; Toyota, Masatsugu; Shimada, Masayoshi; Mekata, Mika; Kurata, Tetsuya; Tasaka, Masao; Morita, Miyo T

2016-01-01

Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the endodermal-amyloplast less 1 ( eal1 ) mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene ( enhancer of eal1 ) mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis .

Reduced starch granule number per chloroplast in the dpe2/phs1 mutant is dependent on initiation of starch degradation.

Science.gov (United States)

Malinova, Irina; Fettke, Joerg

2017-01-01

An Arabidopsis double knock-out mutant lacking cytosolic disproportionating enzyme 2 (DPE2) and the plastidial phosphorylase (PHS1) revealed a dwarf-growth phenotype, reduced starch content, an uneven distribution of starch within the plant rosette, and a reduced number of starch granules per chloroplast under standard growth conditions. In contrast, the wild type contained 5-7 starch granules per chloroplast. Mature and old leaves of the double mutant were essentially starch free and showed plastidial disintegration. Several analyses revealed that the number of starch granules per chloroplast was affected by the dark phase. So far, it was unclear if it was the dark phase per se or starch degradation in the dark that was connected to the observed decrease in the number of starch granules per chloroplast. Therefore, in the background of the double mutant dpe2/phs1, a triple mutant was generated lacking the initial starch degrading enzyme glucan, water dikinase (GWD). The triple mutant showed improved plant growth, a starch-excess phenotype, and a homogeneous starch distribution. Furthermore, the number of starch granules per chloroplast was increased and was similar to wild type. However, starch granule morphology was only slightly affected by the lack of GWD as in the triple mutant and, like in dpe2/phs1, more spherical starch granules were observed. The characterized triple mutant was discussed in the context of the generation of starch granules and the formation of starch granule morphology.

Influence of the gene xthA in the activation of SOS response of Escherichia coli; Influencia del gen xthA en la activacion de la respuesta SOS de Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Dominguez M, V.

2013-07-01

The SOS response is one of the strategies that has Escherichia coli to counteract the lesions in the genetic material. The response is integrated for approximately 60 genes that when are activated they provide to the cell a bigger opportunity to survive. For the activation of this system is necessary that DNA regions of simple chain are generated, in such a way that most of the lesions should be processed, to be able to induce this answer. Some genes that intervene in this procedure, as recO, recB and recJ are recognized since when being exposed to the radiation, their activity SOS is smaller than in a wild strain. In previous works has been studied that to inactivate the genes that are involves in the lesions processing to generate DNA of simple chain, the SOS induction level diminishes with regard to a wild strain, but that when eliminating the genes that are involves directly in the repair, the SOS response increases. In this work a strain with defects in the gene xthA was built, which encodes for an endonuclease AP that participates in the repair mechanism by base excision and was evaluated their sensibility as the activity of the SOS response when exposing it to UV light and gamma radiation. The results showed that the lethality of the strain with the defect is very similar to the wild strain; while the activation level of the SOS response is bigger in comparison with the wild strain when being exposed to UV light; suggesting the existence of an enzyme that recognizes the lesions that produces this radiation, however, is not this the main repair channel, since the survival is similar to that of the wild strain. On the contrary, the results obtained with gamma radiation showed that the lethality diminishes in comparison to that of the wild strain, like the SOS activity; due surely to that the gene product intervenes in the repair for base excision, participating in the formation of the previous substrate to the activation of the SOS response. (Author)

Strain improvement in dye decolourising mutants of Mucor mucedo ...

African Journals Online (AJOL)

STORAGESEVER

2009-12-15

Dec 15, 2009 ... M. mucedo {MMM1-U.V. irradiated mutant and MMM2-EMS (ethyl methyl sulfonate) treated ... tions were induced and two positive mutants (MMM1, .... yeast biofilter for the treatment of a Nigerian fertilizer plant effluent. World J.

SoS Notebook: An Interactive Multi-Language Data Analysis Environment.

Science.gov (United States)

Peng, Bo; Wang, Gao; Ma, Jun; Leong, Man Chong; Wakefield, Chris; Melott, James; Chiu, Yulun; Du, Di; Weinstein, John N

2018-05-22

Complex bioinformatic data analysis workflows involving multiple scripts in different languages can be difficult to consolidate, share, and reproduce. An environment that streamlines the entire processes of data collection, analysis, visualization and reporting of such multi-language analyses is currently lacking. We developed Script of Scripts (SoS) Notebook, a web-based notebook environment that allows the use of multiple scripting language in a single notebook, with data flowing freely within and across languages. SoS Notebook enables researchers to perform sophisticated bioinformatic analysis using the most suitable tools for different parts of the workflow, without the limitations of a particular language or complications of cross-language communications. SoS Notebook is hosted at http://vatlab.github.io/SoS/ and is distributed under a BSD license. bpeng@mdanderson.org.

Effect of radiation doses rate on SOS response induction in irradiated Escherichia coli Cells

International Nuclear Information System (INIS)

Cuetara Lugo, Elizabeth B.; Fuentes Lorenzo, Jorge L.; Almeida Varela, Eliseo; Prieto Miranda, Enrique F.; Sanchez Lamar, Angel; Llagostera Casal, Montserrat

2005-01-01

The present work is aimed to study the effect of radiation dose rate on the induction of SOS response in Escherichia coli cells. We measured the induction of sul A reporter gene in PQ-37 (SOS Chromotest) cells. Lead devises were built with different diameter and these were used for diminishing the dose rate of PX- -30M irradiator. Our results show that radiation doses rate significantly modifies the induction of SOS response. Induction factor increases proportionally to doses rate in Escherichia coli cells defective to nucleotide excision repair (uvrA), but not in wild type cells. We conclude that the dose rate affects the level of induction of SOS response

Lateral root development in the maize (Zea mays) lateral rootless1 mutant.

Science.gov (United States)

Husakova, Eva; Hochholdinger, Frank; Soukup, Ales

2013-07-01

The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1-related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no influences observed on the root apical meristem

Lateral root development in the maize (Zea mays) lateral rootless1 mutant

Science.gov (United States)

Husakova, Eva; Hochholdinger, Frank; Soukup, Ales

2013-01-01

Background and Aims The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. Methods Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. Key Results The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1-related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. Conclusions The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no

SOS response activation and competence development are antagonistic mechanisms in Streptococcus thermophilus.

Science.gov (United States)

Boutry, Céline; Delplace, Brigitte; Clippe, André; Fontaine, Laetitia; Hols, Pascal

2013-02-01

Streptococcus includes species that either contain or lack the LexA-like repressor (HdiR) of the classical SOS response. In Streptococcus pneumoniae, a species which belongs to the latter group, SOS response inducers (e.g., mitomycin C [Mc] and fluoroquinolones) were shown to induce natural transformation, leading to the hypothesis that DNA damage-induced competence could contribute to genomic plasticity and stress resistance. Using reporter strains and microarray experiments, we investigated the impact of the SOS response inducers mitomycin C and norfloxacin and the role of HdiR on competence development in Streptococcus thermophilus. We show that both the addition of SOS response inducers and HdiR inactivation have a dual effect, i.e., induction of the expression of SOS genes and reduction of transformability. Reduction of transformability results from two different mechanisms, since HdiR inactivation has no major effect on the expression of competence (com) genes, while mitomycin C downregulates the expression of early and late com genes in a dose-dependent manner. The downregulation of com genes by mitomycin C was shown to take place at the level of the activation of the ComRS signaling system by an unknown mechanism. Conversely, we show that a ComX-deficient strain is more resistant to mitomycin C and norfloxacin in a viability plate assay, which indicates that competence development negatively affects the resistance of S. thermophilus to DNA-damaging agents. Altogether, our results strongly suggest that SOS response activation and competence development are antagonistic processes in S. thermophilus.

Gamma rays induced bold seeded high yielding mutant in chickpea

International Nuclear Information System (INIS)

Wani, A.A.; Anis, M.

2001-01-01

In pulses especially in chickpea (Cicer arietinum L.), genetic variability has been exhausted due to natural selection and hence conventional breeding methods are not very fruitful. Mutation techniques are the best methods to enlarge the genetically conditioned variability of a species within a short time and have played a significant role in the development of many crop varieties. Investigations on the effects of ionizing radiations and chemical mutagens in induction of macro-mutations have received much attention owing to their utmost importance in plant breeding. The present study reports a bold seeded mutant in chickpea, the most dominating pulse crop on the Indian subcontinent. Fresh seeds of chickpea variety 'Pusa-212' were procured from IARI, New Delhi and treated with different doses/concentrations of gamma rays ( 60 Co source at NBRI, Lucknow) and ethyl methanesulphonate (EMS), individually as well as in combination, to raise the M1 generation. Seeds of M 1 plants were sown to raise M2 plant progenies. A bold seeded mutant was isolated from 400 Gy gamma ray treatments. The mutant was confirmed as true bred, all the mutant seeds gave rise to morphologically similar plants in M 3 , which were quite distinct from the control. The bold seeded mutant showed 'gigas' characteristics and vigorous growth. The plant remained initially straight but later on attained a trailing habit due to heavy secondary branching. The leaves, petioles, flowers, pods and seeds were almost double that of the parent variety, in size. The flowering occurred 10 days later than the parent and maturity was also delayed accordingly. Observations were recorded on various quantitative traits. Plant height and number of primary branches showed a significant improvement over the parent. It is interesting to note that the number of pods and number of seeds per pod significantly decreased. However, the hundred seed weight (31.73±0.59g) in the mutant plants was more than double in the parent

Optimization of mutant recovery from plants obtained from gamma-radiated seeds of winged bean (Psophocarpus tetragonolobus (L) DC)

International Nuclear Information System (INIS)

Klu, J. Y. P.; Harten, A. M. van

2000-01-01

Dry seeds of winged bean (Psophocarpus tetragonolobus (L.) DC) cvs UPS 122 and Kade 6/16 were treated with acute radiation doses of 150 Gy and 250 Gy at a dose rate of 737.32 Gy/hr from a Cobalt-60 gamma source for studies in optimisation of mutant selection in M 2 and M 3 populations. Mature dry pods were harvested at four different locations on each M 1 plant viz. 0.5, 1.0, 1.5 and 2.0 metres from the ground. M 2 seedlings were screened for different groups of chlorophyll deficiencies and their frequencies. Reduction in chlorophyll mutation frequency from the first formed seeds to the latest ones within the M 1 pods has been observed for both cultivars studied. The high degree of chimerism recorded in the M 2 seedlings present in the first-formed seeds in the M 1 pods provides a clear indication that these seeds constitute a zone from which seeds for the M 2 generation have to be harvested in order to give the highest probability for obtaining different types of mutants. On the other hand, significant differences in mutation frequency were not obtained in M 2 seedlings from pods harvested at the various positions on the M 1 plants. M 1 pods can be harvested at any height on the M 1 plants but is preferable to use the earliest mature ones to save time and labour. The zones identified on M 1 plants in this investigation coupled with the use of the 'spare' or 'remnant' seed selection method, should provide an improved method for mutation breeding in a viny legume like the winged bean. (au)

Identification of the AQP members involved in abiotic stress responses from Arabidopsis.

Science.gov (United States)

Feng, Zhi-Juan; Xu, Sheng-Chun; Liu, Na; Zhang, Gu-Wen; Hu, Qi-Zan; Xu, Zhao-Shi; Gong, Ya-Ming

2018-03-10

Aquaporins (AQPs) constitute a highly diverse family of water channel proteins that play crucial biological functions in plant growth and development and stress physiology. In Arabidopsis, 35 AQPs are classified into four subfamilies (PIPs, TIPs, NIPs and SIPs). However, knowledge about the roles of different subfamily AQPs remains limited. Here, we explored the chromosomal location, gene structure and expression patterns of all AQPs in different tissues or under different abiotic stresses based on available microarray data. Tissue expression analysis showed that different AQPs had various expression patterns in tissues (root, leaf, flower and seed). Expression profiles under stress conditions revealed that most AQPs were responsive to osmotic, salt and drought stresses. Phenotypic and physiological identification showed that Tip2;2 loss-of-function mutant exhibited less sensitive to abiotic stresses (mannitol, NaCl and PEG) compared with wild-type, as evident by analysis of germination rate, root growth, survival rate, ion leakage, malondialdehyde (MDA) and proline contents. Mutant of TIP2;2 modulated the transcript levels of SOS1, SOS2, SOS3, DREB1A, DREB2A and P5CS1, under abiotic stress conditions. This study provides a basis for further functional identification of stress-related candidate AQPs in Arabidopsis. Copyright © 2017 Elsevier B.V. All rights reserved.

Escherichia coli DinB inhibits replication fork progression without significantly inducing the SOS response.

Science.gov (United States)

Mori, Tetsuya; Nakamura, Tatsuro; Okazaki, Naoto; Furukohri, Asako; Maki, Hisaji; Akiyama, Masahiro Tatsumi

2012-01-01

The SOS response is readily triggered by replication fork stalling caused by DNA damage or a dysfunctional replicative apparatus in Escherichia coli cells. E. coli dinB encodes DinB DNA polymerase and its expression is upregulated during the SOS response. DinB catalyzes translesion DNA synthesis in place of a replicative DNA polymerase III that is stalled at a DNA lesion. We showed previously that DNA replication was suppressed without exogenous DNA damage in cells overproducing DinB. In this report, we confirm that this was due to a dose-dependent inhibition of ongoing replication forks by DinB. Interestingly, the DinB-overproducing cells did not significantly induce the SOS response even though DNA replication was perturbed. RecA protein is activated by forming a nucleoprotein filament with single-stranded DNA, which leads to the onset of the SOS response. In the DinB-overproducing cells, RecA was not activated to induce the SOS response. However, the SOS response was observed after heat-inducible activation in strain recA441 (encoding a temperature-sensitive RecA) and after replication blockage in strain dnaE486 (encoding a temperature-sensitive catalytic subunit of the replicative DNA polymerase III) at a non-permissive temperature when DinB was overproduced in these cells. Furthermore, since catalytically inactive DinB could avoid the SOS response to a DinB-promoted fork block, it is unlikely that overproduced DinB takes control of primer extension and thus limits single-stranded DNA. These observations suggest that DinB possesses a feature that suppresses DNA replication but does not abolish the cell's capacity to induce the SOS response. We conclude that DinB impedes replication fork progression in a way that does not activate RecA, in contrast to obstructive DNA lesions and dysfunctional replication machinery.

A syntactic commutativity format for SOS

NARCIS (Netherlands)

Mousavi, M.R.; Reniers, M.A.; Groote, J.F.

2005-01-01

Considering operators defined using Structural Operational Semantics (SOS), commutativity axioms are intuitive properties that hold for many of them. Proving this intuition is usually a laborious task, requiring several pages of boring and standard proof. To save this effort, we propose a syntactic

Motion-insensitive carotid intraplaque hemorrhage imaging using 3D inversion recovery preparation stack of stars (IR-prep SOS) technique.

Science.gov (United States)

Kim, Seong-Eun; Roberts, John A; Eisenmenger, Laura B; Aldred, Booth W; Jamil, Osama; Bolster, Bradley D; Bi, Xiaoming; Parker, Dennis L; Treiman, Gerald S; McNally, J Scott

2017-02-01

Carotid artery imaging is important in the clinical management of patients at risk for stroke. Carotid intraplaque hemorrhage (IPH) presents an important diagnostic challenge. 3D magnetization prepared rapid acquisition gradient echo (MPRAGE) has been shown to accurately image carotid IPH; however, this sequence can be limited due to motion- and flow-related artifact. The purpose of this work was to develop and evaluate an improved 3D carotid MPRAGE sequence for IPH detection. We hypothesized that a radial-based k-space trajectory sequence such as "Stack of Stars" (SOS) incorporated with inversion recovery preparation would offer reduced motion sensitivity and more robust flow suppression by oversampling of central k-space. A total of 31 patients with carotid disease (62 carotid arteries) were imaged at 3T magnetic resonance imaging (MRI) with 3D IR-prep Cartesian and SOS sequences. Image quality was determined between SOS and Cartesian MPRAGE in 62 carotid arteries using t-tests and multivariable linear regression. Kappa analysis was used to determine interrater reliability. In all, 25 among 62 carotid plaques had carotid IPH by consensus from the reviewers on SOS compared to 24 on Cartesian sequence. Image quality was significantly higher with SOS compared to Cartesian (mean 3.74 vs. 3.11, P SOS acquisition yielded sharper image features with less motion (19.4% vs. 45.2%, P SOS (kappa = 0.89), higher than that of Cartesian (kappa = 0.84). By minimizing flow and motion artifacts and retaining high interrater reliability, the SOS MPRAGE has important advantages over Cartesian MPRAGE in carotid IPH detection. 1 J. Magn. Reson. Imaging 2017;45:410-417. © 2016 International Society for Magnetic Resonance in Medicine.

Isolation of new gravitropic mutants under hypergravity conditions

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Akiko Mori

2016-09-01

Full Text Available Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upwards. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes. In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using Next-Generation Sequencing (NGS and Single Nucleotide Polymorphism (SNP-based markers. Using the endodermal-amyloplast less 1 (eal1 mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene (enhancer of eal1 mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis.

A Small-Molecule Inducible Synthetic Circuit for Control of the SOS Gene Network without DNA Damage.

Science.gov (United States)

Kubiak, Jeffrey M; Culyba, Matthew J; Liu, Monica Yun; Mo, Charlie Y; Goulian, Mark; Kohli, Rahul M

2017-11-17

The bacterial SOS stress-response pathway is a pro-mutagenic DNA repair system that mediates bacterial survival and adaptation to genotoxic stressors, including antibiotics and UV light. The SOS pathway is composed of a network of genes under the control of the transcriptional repressor, LexA. Activation of the pathway involves linked but distinct events: an initial DNA damage event leads to activation of RecA, which promotes autoproteolysis of LexA, abrogating its repressor function and leading to induction of the SOS gene network. These linked events can each independently contribute to DNA repair and mutagenesis, making it difficult to separate the contributions of the different events to observed phenotypes. We therefore devised a novel synthetic circuit to unlink these events and permit induction of the SOS gene network in the absence of DNA damage or RecA activation via orthogonal cleavage of LexA. Strains engineered with the synthetic SOS circuit demonstrate small-molecule inducible expression of SOS genes as well as the associated resistance to UV light. Exploiting our ability to activate SOS genes independently of upstream events, we further demonstrate that the majority of SOS-mediated mutagenesis on the chromosome does not readily occur with orthogonal pathway induction alone, but instead requires DNA damage. More generally, our approach provides an exemplar for using synthetic circuit design to separate an environmental stressor from its associated stress-response pathway.

Radiation induced mutants in cape-gooseberry (Physalis peruviana L.)

International Nuclear Information System (INIS)

Gupta, S.K.; Roy, S.K.

1986-01-01

Dry seeds of Physalis peruviana (n=24) were irradiated with different doses of gamma-rays. The M 1 plants were grown to maturity and their seeds collected and sown separately for M 2 generation. Mutants were isolated from M 2 seedlings and plants. Mutant characters obtained were virido-albino chlorophyllous, high yielding, small leaf and fruit, semi-sterile and curly leaf type etc. The high yielding and small leaf and fruit mutants bred true in M 3 and M 4 generation reproducing the characters of the M 2 generation. (author)

Cadmium Accumulation and Its Toxicity in Brittle Culm 1 (bc1, a Fragile Rice Mutant

Directory of Open Access Journals (Sweden)

Guo-sheng SHAO

2007-09-01

Full Text Available Cadmium (Cd accumulation and toxicity in rice plants were characterized and identified by using brittle culm 1 (bc1, a fragile rice mutant and its wild type (Shuangkezao, an indica rice as materials by hydroponics. The low Cd level didn't obviously affect the growth parameters in both rice genotypes, but under high Cd levels (1.0 and 5.0 μmol/L, the growth of both rice plants were substantially inhibited. Moreover, bc1 tended to suffer more seriously from Cd toxicity than Shuangkezao. Cd accumulation in both rice plants increased with the increase of Cd levels. There was a significant difference in Cd accumulation between the two rice genotypes with constantly higher Cd concentration in bc1, which also accumulated more Cd at 0, 0.1, and 1.0 μmol/L Cd levels. The same case was found in the two rice plants grown on Cd-contaminated soil. This suggested that cell wall might play an important role in Cd accumulation in rice plants by the physiological mechanisms. The malondialdehyde (MDA content, superoxide dismutase (SOD and peroxidase (POD activities in rice plants were affected differently under Cd treatments, and which implied that POD might play the main role in detoxifying active oxygen free radical. A significant difference in antioxidative system between the two rice genotypes was found with constantly higher MDA content, SOD and POD activities in bc1. In summary, bc1 accumulated more Cd and appeared to be more sensitive to Cd stress compared with its wild type.

Induction of short culm mutants for bread wheat by using gamma rays

International Nuclear Information System (INIS)

Sobieh, S.S.

2002-01-01

This investigation was conducted at the experimental farm of plant research department, nuclear research center, atomic energy authority, Inshas in order to select some short culm mutants from the local wheat varieties; Sid's-5, Sid's-6 and Sid's-7 after gamma irradiation. The obtained results indicated that: 1-M 4 mutants progenies retained the features of their M 3 selections. 2-Some short culm mutants exhibited high grain yield/plant as compared to their original varieties. 3-There were significant decreases in plant height varied from 21.4 to 35.4%. This reduction was due to the shorting of culm inter nods length. As well as, the reduction diameter/culm especially diameter of the inter nods/culm did not differed between original varieties and the mutants. 4-The correlation between grain yield/plant and number of spikes/plant was positive and highly significant for most mutants and the original varieties as well. Data also showed that there were positive relationship between grain yield/plant and number of grains/spike and and length of the inter nods/culm. Positive or negative association between grain yield/plant and plant height as well as diameters of inter nods/culm for mutants and original varieties were detected

SOS hotline for women victims of discrimination at the workplace

OpenAIRE

Dobrosavljević-Grujić Ljiljana S.

2004-01-01

SOS hotline for women victims of discrimination at the workplace offers free legal assistance to women, whenever their labor rights are endangered. If the dispute cannot be resolved peacefully by mediation between employer and employees, female lawyer skilled for the labor law starts up judicial proceedings. Some characteristic cases of discrimination of women from the practice of SOS telephone, such as dismissal from the work, physical violence and sexual blackmail, are presented in the paper.

A novel two-step method for screening shade tolerant mutant plants via dwarfism

Science.gov (United States)

When subjected to shade, plants undergo rapid shoot elongation, which often makes them more prone to disease and mechanical damage. It has been reported that, in turfgrass, induced dwarfism can enhance shade tolerance. Here, we describe a two-step procedure for isolating shade tolerant mutants of ...

Design rules for RCA self-aligned silicon-gate CMOS/SOS process

Science.gov (United States)

1977-01-01

The CMOS/SOS design rules prepared by the RCA Solid State Technology Center (SSTC) are described. These rules specify the spacing and width requirements for each of the six design levels, the seventh level being used to define openings in the passivation level. An associated report, entitled Silicon-Gate CMOS/SOS Processing, provides further insight into the usage of these rules.

A hierarchy of SOS rule formats

NARCIS (Netherlands)

Groote, J.F.; Mousavi, M.R.; Reniers, M.A.; Mosses, P.D.; Ulidowski, I.

2006-01-01

In 1981 Structural Operational Semantics (SOS) was introduced as a systematic way to define operational semantics of programming languages by a set of rules of a certain shape [G.D. Plotkin. A structural approach to operational semantics. Technical Report DAIMI FN-19, Computer Science Department,

Pollen irradiation method to obtain mutants in cucumber

International Nuclear Information System (INIS)

Iida, S.; Amano, E.

1988-01-01

Seed irradiation for mutation induction in dioecious crops like cucumber is not very useful because chimerism of the mutated tissues makes the segregation of mutants in the M 2 generation nearly impossible. This problem does not exist with pollen irradiation. Cucumber (Cucumis sativus L. var. Nishikisuyo) was used for a model experiment. The petals of male and female flowers were closed by pinching with binding wire before flowering to prevent pollination by insects. On the flowering day, the male flowers were collected and irradiated with 1kR to 10 kR of acute gamma rays (137-Cs), then used to pollinate the female flowers. The M 1 seeds thus obtained are not chimeric but heterozygous for induced mutations. When planted, no mutant phenotype appeared. Selfing within a plant lead to segregation of mutants in the M 2 generation. Seedling examination revealed eight mutants. One mutant line, in which the shape of leaves changed from pentagonal to round heart shape, was found under field conditions. The optimal dose for pollen irradiation seems to be between 2 kR and 4kR

Understanding the Biological Roles of Pectins in Plants through Physiological and Functional Characterizations of Plant and Fungal Mutants

DEFF Research Database (Denmark)

Stranne, Maria

The plant cell wall is a dynamic structure and it is involved in regulating a number of physiological features of plants such as physical strength, growth, cell differentiation, intercellular communication, water movement and defense responses. Pectins constitute a major class of plant cell wall...... polysaccharides and consist of backbones rich in galacturonic acids, which are decorated with a range of functional groups including acetyl esters and arabinan sidechains. Although much effort has been made to uncover biological functions of pectins in plants and remarkable progresses have taken place, many...... aspects remain elusive. Studies described in this thesis aimed at gaining new insights into the biological roles of pectin acetylation and arabinosylation in the model plant Arabidopsis thaliana. The thesis consists of four chapters: physiological characterization of cell wall mutants affected in cell...

Metabolic analysis of the increased adventitious rooting mutant of Artemisia annua reveals a role for the plant monoterpene borneol in adventitious root formation.

Science.gov (United States)

Tian, Na; Liu, Shuoqian; Li, Juan; Xu, Wenwen; Yuan, Lin; Huang, Jianan; Liu, Zhonghua

2014-08-01

Adventitious root (AR) formation is a critical process for plant clonal propagation. The role of plant secondary metabolites in AR formation is still poorly understood. Chemical and physical mutagenesis in combination with somatic variation were performed on Artemisia annua in order to obtain a mutant with changes in adventitious rooting and composition of plant secondary metabolites. Metabolic and morphological analyses of the iar (increased adventitious rooting) mutant coupled with in vitro assays were used to elucidate the relationship between plant secondary metabolites and AR formation. The only detected differences between the iar mutant and wild-type were rooting capacity and borneol/camphor content. Consistent with this, treatment with borneol in vitro promoted adventitious rooting in wild-type. The enhanced rooting did not continue upon removal of borneol. The iar mutant displayed no significant differences in AR formation upon treatment with camphor. Together, our results suggest that borneol promotes adventitious rooting whereas camphor has no effect on AR formation. © 2013 Scandinavian Plant Physiology Society.

SOS hotline for women victims of discrimination at the workplace

Directory of Open Access Journals (Sweden)

Dobrosavljević-Grujić Ljiljana S.

2004-01-01

Full Text Available SOS hotline for women victims of discrimination at the workplace offers free legal assistance to women, whenever their labor rights are endangered. If the dispute cannot be resolved peacefully by mediation between employer and employees, female lawyer skilled for the labor law starts up judicial proceedings. Some characteristic cases of discrimination of women from the practice of SOS telephone, such as dismissal from the work, physical violence and sexual blackmail, are presented in the paper.

The use of Stationary Phase Optimized Selectivity Liquid Chromatography for the development of herbal fingerprints to detect targeted plants in plant food supplements.

Science.gov (United States)

Deconinck, E; Djiogo, C A Sokeng; Kamugisha, A; Courselle, P

2017-08-01

The consumption of plant food supplements is increasing steadily and more and more, these products are bought through internet. Often the products sold through internet are not registered or declared with a national authority, meaning that no or minimal quality control is performed and that they could contain herbs or plants that are regulated. Stationary Phase Optimized Selectivity Liquid Chromatography (SOS-LC) was evaluated for the development of specific fingerprints, to be used for the detection of targeted plants in plant food supplements. Three commonly used plants in plant food supplements and two regulated plants were used to develop fingerprints with SOS-LC. It was shown that for all plants specific fingerprints could be obtained, allowing the detection of these targeted plants in triturations with different herbal matrices as well as in real samples of suspicious supplements seized by the authorities. For three of the five plants a more specific fingerprint was obtained, compared to the ones developed on traditional columns described in literature. It could therefore be concluded that the combination of segments of different types of stationary phases, as used in SOS-LC, has the potential of becoming a valuable tool in the quality control and the identification of crude herbal or plant material and in the detection of regulated plants in plant food supplements or other herbal preparations. Copyright © 2017 Elsevier B.V. All rights reserved.

Induction of mutagenized tomato populations for investigation on agronomic traits and mutant phenotyping

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Rafiul Amin Laskar

2018-01-01

Full Text Available Global demand for tomato production increased tremendously due to its diverse utility in raw, cooked and processed form of food. This necessitates the continued supply of highly nutritious and better yielding improved cultivars to the producers, considering the rapid changing agro-climatic condition. In this study, induced mutant tomato populations of widely recommended tomato genotype Arka Vikas (Sel-22 were generated using chemical mutagen ethyl methane sulfonate (EMS, hydrazine hydrates (HZ and their combined treatments. In the in vitro study, a gradual reduction in germination percentage and seedling height occurred with the increasing concentrations of mutagens. Combination of EMS and HZ caused maximum biological inhibition followed by EMS and HZ treatments alone in M1 generation. The rate of survival and fertility in M1 plants of tomato was found highly affected due to mutagenic treatment, in which sensitivity toward combined treatment was found highest followed by EMS and HZ. Inspection on induced phenotypic variations in individual plants of M2 population resulted in identification and isolation of wide range of mutants with altered phenotypes. Highest mutation frequency was resulted by combined mutagens followed by the EMS and HZ treatment. Agronomic trait analyses showed intra and inter treatment variations in three quantitative traits (Plant height, fertile branch per plant and fruits per plant of M2 mutagenized population. Assessment on rate of mutant recovery in M2 population showed highest mutant recovery is possible with combination treatments and then 0.02% HZ followed by 0.02% EMS. In the present study, phenotyping of the mutants revealed that vegetative organs (‘plant size’, ‘plant habit’ and ‘leaf morphology’ was the most sensitive category (69.33% to which most of the mutant belongs, followed by ‘fruit color and size’ (20.27% and ‘germination’ (9.79%. Comparative investigation on number of mutants and

Genetic analysis of the SOS response of Escherichia coli

International Nuclear Information System (INIS)

Mount, D.W.; Wertman, K.F.; Ennis, D.G.; Peterson, K.R.; Fisher, B.L.; Lyons, G.

1983-01-01

In the SOS response, a large number of E. coli genes having different functions are derepressed when the cellular DNA is damaged. This derepression occurs through inactivation of a repressor, the product of the lexA gene, by a protease activity of the recA gene product. The protease is thought to be activated in response to changes in DNA metabolism which follow the damage. After the SOS functions have acted, the protease activity declines and repression is again established. Because the DNA sequence of both lexA and recA have been determined, it is possible to induce many mutations in their regulatory and structural regions in order to analyze further the control of the SOS response. We are studying the effects of mutations in both the lexA and recA regulatory regions, and mutations which affect the protease activity or the sensitivity of repressor to the protease. Finally, we are using genetic methods to analyze a newly identified requirement for recA protein, induced mutagenesis in cells lacking repressor. 16 references, 3 figures

Transcriptional Responses of the Bdtf1-Deletion Mutant to the Phytoalexin Brassinin in the Necrotrophic Fungus Alternaria brassicicola

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Yangrae Cho

2014-07-01

Full Text Available Brassica species produce the antifungal indolyl compounds brassinin and its derivatives, during microbial infection. The fungal pathogen Alternaria brassicicola detoxifies brassinin and possibly its derivatives. This ability is an important property for the successful infection of brassicaceous plants. Previously, we identified a transcription factor, Bdtf1, essential for the detoxification of brassinin and full virulence. To discover genes that encode putative brassinin-digesting enzymes, we compared gene expression profiles between a mutant strain of the transcription factor and wild-type A. brassicicola under two different experimental conditions. A total of 170 and 388 genes were expressed at higher levels in the mutants than the wild type during the infection of host plants and saprophytic growth in the presence of brassinin, respectively. In contrast, 93 and 560 genes were expressed, respectively, at lower levels in the mutant than the wild type under the two conditions. Fifteen of these genes were expressed at lower levels in the mutant than in the wild type under both conditions. These genes were assumed to be important for the detoxification of brassinin and included Bdtf1 and 10 putative enzymes. This list of genes provides a resource for the discovery of enzyme-coding genes important in the chemical modification of brassinin.

Paraísos fiscales en la globalización financiera

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Alberto Garzón Espinosa

2011-10-01

Full Text Available Los paraísos fiscales son espacios financieros caracterizados ante todo por su baja o nula tributación. En este artículo examinaremos con detalle el uso de los mismos por parte de los agentes económicos, centrándonos especialmente en los bancos y los fondos de inversión colectiva. No obstante, como elementos clave de un nuevo contexto financiero los paraísos fiscales han tenido un papel fundamental en la gestación y expansión de todas las crisis financieras recientes, razón por la cual también estudiaremos las consecuencias que la existencia misma de los paraísos fiscales tiene sobre la economía y el sistema financiero.Palabras clave: Paraísos fiscales, globalización financiera, neoliberalismo_______________Abstract:The tax haven are financial spaces which it characterize for its shorts taxations. In this article we will analyze the use of that by the economic agent, specially the banks and the funds of collective investment. However, like key elements of the new financial context, the tax haven was been a leading role in gestation and expansion of all financial crisis of our days. For that, we will study the consequences of this fact in the economy and financial system.Keywords: tax haven, financial globalization, neoliberalism.

Drought resistant rice mutants, characteristics and discussions on possibilities for planting them in some Arab Countries which import rice

International Nuclear Information System (INIS)

Abo-Hegazi, A.M.T.

1994-01-01

A number of drought resistant mutants of rice were produced from ordinary rice varieties being planted in several parts of Egypt through utilization of gamma rays as a mutagen. The mutants have water requirements less than one half of that of their mother varieties. According to official data, authorities in Egypt insure about 18000 M 3 of irrigation water for every hectare (10000 M 2 ) of rice and about 6700 M 3 , 6900 M 3 for every hectare of corn and ground nuts, respectively. Peanuts and corn are summer crops like the drought resistant rice mutants. The mentioned mutants can produce good yield under water requirements very near to that of corn and peanuts. The wide gap in agricultural food stuffs for the Arab Countries (more than 20000 million US $ annually) includes rice imports usually exceeds 700 million US $ per year> Rice imports of Arab Countries such as Saudi Arabia, Yemen, Syria, Libya and the Sudan, reached 180, 47, 21, 16 and 14 million US $ in 1988 as an example. Such countries could make use of the drought resistant rice mutants for plantation on water requirements very near to those of usual summer crops such as corn and peanuts which is significantly less than one half of water requirements of their mother varieties. Some characteristics of such mutants as well as discussions on possibilities for planting them in some of the nominated Arab Countries are presented. However, arrangements for ensuring the minimum water requirements during the growing period irrespective to rain which in many cases did not accord the growing period of the mutants should be taken if such countries wants to make use of the drought resistant rice mutants. The author believe that most if not all requirements of rice of such countries could locally be ensured through planting of the above mentioned rice mutants. In this case, maximizing the efficiency of utilizing the limited water resources of such countries could also be counted as another cause for presenting this

Productive mutants of niger

International Nuclear Information System (INIS)

Misra, R.C.

2001-01-01

Seeds of six niger (Guizotia abyssinica Cass.) varieties ('GA-10', 'ONS-8', 'IGP-72', 'N-71', 'NB-9' and 'UN-4') were treated with 0.5, 0.75 and 1% ethyl methanesulphonate. After four generations of selection, 29 mutant lines were developed and those were evaluated from 1990-92 during Kharif (July to October) and Rabi (December to March) seasons. Average plant characteristics and yield data of four high yielding mutants along with 'IGP-76' (National Check), GA-10 (Zonal Check) and 'Semiliguda Local' (Local Check) are presented

Effect of iso-osmotic salt and water stress in relation to adjustment on mutant sugarcane (Saccharum officinarum L.) plant lines

International Nuclear Information System (INIS)

Ahuja, Akash V.; Kalwade, Sachin B.; Nikam, Ashok A.; Devarumath, R.M.; Chauvan, Viraj S.; Kanse, Sangram S.

2014-01-01

Gamma radiation induced mutagenesis followed by in vitro selection was employed for salt tolerance in popular sugarcane (Saccharum officinarum L.) cv.CoM0265. Assimilated regenerated mutant plantlets were planted on control as well as salt affected soil. Mutants which showed relatively good response with respect to its quantitative and qualitative parameters were selected for priming experiment. Nine mutants and its respective control and parent control which are known to vary in salt tolerance under field conditions were studied. In order to discriminate between the ionic and osmotic components of salt stress, mutant plants were treated with NaCl salt (100 mM) or polyethylene glycol-PEG 8000 solutions (20%) for 10 days. Both NaCI and PEG treatment significantly reduced leaf width, number of green leaves and chlorophyll stability index. Osmotic adjustment indicated that the NaCI and PEG stress lead to accumulation of osmolytes, however sugar level changes non significantly. The ion concentration was drastically affected upon NaCI treatment, whereas PEG stress accumulated relatively less amount of Na + ions in comparison to NaCl. However, there was an increase in K + concentration upon PEG treatment, whereas NaCI stress accumulated less K + concentration with respect to PEG and control. The NaCI and PEG treated mutant plants showed increased activities of superoxide dismutase (SOD) and Catalase (CAT) in comparison to its control and parent control. Among the mutant selected gamma rays irradiation in corporation with enhanced tolerance to abiotic stress is one of the important goals for the biotechnological improvement of crop plants. Enhanced salinity tolerance may prove beneficial to improve the competitiveness of the popular sugarcane cultivars and their commercial cultivation in saline areas. (author)

An induced mutant of Coastcross 1 Bermudagrass with improved winter hardiness

International Nuclear Information System (INIS)

Burton, G.W.; Constantin, M.J.; Dobson, J.W. Jr.; Hanna, W.W.; Powell, J.B.

1980-01-01

Coastcross 1 bermudagrass, a sterile F 1 hybrid, (Coastal x PI 255445) establishes faster, yields as much dry matter, is 12% more digestible, and gives 30-35% better daily gains and liveweight gains per ha when fed to cattle than does the Coastal clone but fails to develop rhizomes and lacks the winter hardiness of Coastal. To create a winter hardy mutant, 500,000 green stems were exposed to 7000 rad of 60 -Co rays at Oak Ridge, TN June 21, 1971 and were immediately planted at Blairsville, GA where relatively severe winters occur frequently. One of 4 plants surviving the 1971-72 winter was like Coastcross 1 in yield, in vitro dry matter digestibility and appearance in a 3-yr test during mild winters at Tifton, GA. Following the moderate winter of 1976-77, Coastcross 1-M3 yielded more than Coastcross 1 but only about half as much as Coastal. The severe winter of 1977-78 destroyed about 98% of the plants of Coastcross 1 and Coastcross 1-M3 but reduced the stand of Coastal very little. The small gain in winter hardiness by Coastcross 1-M3 suggests that several genes control the winter hardiness of well-established Coastal bermudagrass. (author)

Approach for targeting Ras with small molecules that activate SOS-mediated nucleotide exchange.

Science.gov (United States)

Burns, Michael C; Sun, Qi; Daniels, R Nathan; Camper, DeMarco; Kennedy, J Phillip; Phan, Jason; Olejniczak, Edward T; Lee, Taekyu; Waterson, Alex G; Rossanese, Olivia W; Fesik, Stephen W

2014-03-04

Aberrant activation of the small GTPase Ras by oncogenic mutation or constitutively active upstream receptor tyrosine kinases results in the deregulation of cellular signals governing growth and survival in ∼30% of all human cancers. However, the discovery of potent inhibitors of Ras has been difficult to achieve. Here, we report the identification of small molecules that bind to a unique pocket on the Ras:Son of Sevenless (SOS):Ras complex, increase the rate of SOS-catalyzed nucleotide exchange in vitro, and modulate Ras signaling pathways in cells. X-ray crystallography of Ras:SOS:Ras in complex with these molecules reveals that the compounds bind in a hydrophobic pocket in the CDC25 domain of SOS adjacent to the Switch II region of Ras. The structure-activity relationships exhibited by these compounds can be rationalized on the basis of multiple X-ray cocrystal structures. Mutational analyses confirmed the functional relevance of this binding site and showed it to be essential for compound activity. These molecules increase Ras-GTP levels and disrupt MAPK and PI3K signaling in cells at low micromolar concentrations. These small molecules represent tools to study the acute activation of Ras and highlight a pocket on SOS that may be exploited to modulate Ras signaling.

Identification and Map-Based Cloning of the Light-Induced Lesion Mimic Mutant 1 (LIL1) Gene in Rice.

Science.gov (United States)

Zhou, Qian; Zhang, Zhifei; Liu, Tiantian; Gao, Bida; Xiong, Xingyao

2017-01-01

The hypersensitive response (HR) is a mechanism by which plants prevent the spread of pathogen. Despite extensive study, the molecular mechanisms underlying HR remain poorly understood. Lesion mimic mutants (LMMs), such as LIL1 that was identified in an ethylmethane sulfonate mutagenized population of Indica rice ( Oryza sativa L. ssp. Indica ) 93-11, can be used to study the HR. Under natural field conditions, the leaves of LIL1 mutant plants exhibited light-induced, small, rust-red lesions that first appeared at the leaf tips and subsequently expanded throughout the entire leaf blade to the leaf sheath. Histochemical staining indicated that LIL1 lesions displayed an abnormal accumulation of reactive oxygen species (ROS) and resulted from programmed cell death (PCD). The LIL1 mutants also displayed increased expression of defense-related genes and enhanced resistance to rice blast fungus ( Magnaporthe grisea ). Genetic analysis showed that mutation of LIL1 created a semi-dominant allele. Using 1,758 individuals in the F 2 population, LIL1 was mapped in a 222.3 kb region on the long arm of chromosome 7. That contains 12 predicted open reading frames (ORFs). Sequence analysis of these 12 candidate genes revealed a G to A base substitution in the fourth exon of LOC_Os07g30510, a putative cysteine-rich receptor-like kinase (CRK), which led to an amino acid change (Val 429 to Ile) in the LIL1 protein. Comparison of the transcript accumulation of the 12 candidate genes between LIL1 and 93-11 revealed that LOC_Os07g30510 was up-regulated significantly in LIL1 . Overexpression of the LOC_Os07g30510 gene from LIL1 induced a LIL1 -like lesion phenotype in Nipponbare. Thus, LIL1 is a novel LMM in rice that will facilitate the further study of the molecular mechanisms of HR and the rice blast resistance.

Validation of the Chinese Version of the Sense of Self (SOS) Scale

Science.gov (United States)

King, Ronnel B.; Ganotice, Fraide A., Jr.; Watkins, David A.

2012-01-01

This study explored the cross-cultural applicability of the Sense of Self (SOS) Scale in the Hong Kong Chinese cultural context. The SOS Scale is a 26-item questionnaire designed to measure students' sense of purpose, self-reliance, and self-concept in school. Six hundred ninety-seven Hong Kong Chinese high school students participated in the…

early maturing mutants in Indica rice and their traits

International Nuclear Information System (INIS)

Chen Xiulan; He Zhentian; Han Yuepeng; Liu Xueyu; Yang Hefeng; Xu Chenwu; Gu Shiliang

1998-01-01

The correlation and genetic parameters of eleven agronomic characters of 50 early mature lines induced from late mature cultivar, IR 1529-68-3-2 were studied by morphological classification and correlation and regression analysis. The results showed that: 1. The early mutants could be divided into two ecotype: early mature type and medium mature type of mid-maturity rice. 2. The 1000-grain weight of early mutants negatively correlated with the length of growing period. 3. According to direct path coefficients, the relation with heading period of early mutants was in order of 1000-grain-weight>plant height>seed sterility. 4.The higher heritability in broad sense were found in plant height, 1000 grain weight and heading period of the early mutants

Identification of a novel ga-related bush mutant in pumpkin (cucurbita moschata duchesne)

International Nuclear Information System (INIS)

Wu, T.; Cao, J.

2015-01-01

Pumpkin (Cucurbita moschata Duchesne) bush mutant plants were characterized by short stems. The sensitivity of pumpkin bush mutant plants to exogenous hormones was identified in this study. Results revealed that internode elongation of bush mutant plants could respond to gibberellins (GA4+7 and GA3), but not to indole acetic acid (IAA) and brassinosteroids (BR); by contrast, the mutant phenotype of bush mutant plants could not be fully rescued by GA4+7 and GA3. The internode of bush mutant plants yielded a lower KS expression level than that of vine plants. Therefore, pumpkin bush mutant plants were designated as GA-related mutant plants eliciting a partial response to GAs; the action of IAA and BR might not be involved in the internode growth of pumpkin bush mutant plants, specifically Cucurbita moschata Duch. (author)

A sorghum (Sorghum bicolor mutant with altered carbon isotope ratio.

Directory of Open Access Journals (Sweden)

Govinda Rizal

Full Text Available Recent efforts to engineer C4 photosynthetic traits into C3 plants such as rice demand an understanding of the genetic elements that enable C4 plants to outperform C3 plants. As a part of the C4 Rice Consortium's efforts to identify genes needed to support C4 photosynthesis, EMS mutagenized sorghum populations were generated and screened to identify genes that cause a loss of C4 function. Stable carbon isotope ratio (δ13C of leaf dry matter has been used to distinguishspecies with C3 and C4 photosynthetic pathways. Here, we report the identification of a sorghum (Sorghum bicolor mutant with a low δ13C characteristic. A mutant (named Mut33 with a pale phenotype and stunted growth was identified from an EMS treated sorghum M2 population. The stable carbon isotope analysis of the mutants showed a decrease of 13C uptake capacity. The noise of random mutation was reduced by crossing the mutant and its wildtype (WT. The back-cross (BC1F1 progenies were like the WT parent in terms of 13C values and plant phenotypes. All the BC1F2 plants with low δ13C died before they produced their 6th leaf. Gas exchange measurements of the low δ13C sorghum mutants showed a higher CO2 compensation point (25.24 μmol CO2.mol-1air and the maximum rate of photosynthesis was less than 5μmol.m-2.s-1. To identify the genetic determinant of this trait, four DNA pools were isolated; two each from normal and low δ13C BC1F2 mutant plants. These were sequenced using an Illumina platform. Comparison of allele frequency of the single nucleotide polymorphisms (SNPs between the pools with contrasting phenotype showed that a locus in Chromosome 10 between 57,941,104 and 59,985,708 bps had an allele frequency of 1. There were 211 mutations and 37 genes in the locus, out of which mutations in 9 genes showed non-synonymous changes. This finding is expected to contribute to future research on the identification of the causal factor differentiating C4 from C3 species that can be used

Functional consequences of inducible genetic elements from the p53 SOS response in a mammalian organ system.

Science.gov (United States)

Guthrie, O'neil W

2017-10-01

In response to DNA damage from ultraviolet (UV) radiation, bacteria deploy the SOS response in order to limit cell death. This bacterial SOS response is characterized by an increase in the recA gene that transactivates expression of multiple DNA repair genes. The current series of experiments demonstrate that a mammalian organ system (the cochlea) that is not evolutionarily conditioned to UV radiation can elicit SOS responses that are reminiscent of that of bacteria. This mammalian SOS response is characterized by an increase in the p53 gene with activation of multiple DNA repair genes that harbor p53 response elements in their promoters. Furthermore, the experimental results provide support for the notion of a convergent trigger paradox, where independent SOS triggers facilitate disparate physiologic sequelae (loss vs. recovery of function). Therefore, it is proposed that the mammalian SOS response is multifunctional and manipulation of this endogenous response could be exploited in future biomedical interventions. Copyright © 2017 Elsevier Inc. All rights reserved.

Identification of a novel streptococcal gene cassette mediating SOS mutagenesis in Streptococcus uberis

NARCIS (Netherlands)

Varhimo, Emilia; Savijoki, Kirsi; Jalava, Jari; Kuipers, Oscar P.; Varmanen, Pekka

Streptococci have been considered to lack the classical SOS response, defined by increased mutation after UV exposure and regulation by LexA. Here we report the identification of a potential self-regulated SOS mutagenesis gene cassette in the Streptococcaceae family. Exposure to UV light was found

Enhanced transpiration rate in the high pigment 1 tomato mutant and its physiological significance.

Science.gov (United States)

Carvalho, R F; Aidar, S T; Azevedo, R A; Dodd, I C; Peres, L E P

2011-05-01

Tomato high pigment (hp) mutants represent an interesting horticultural resource due to their enhanced accumulation of carotenoids, flavonoids and vitamin C. Since hp mutants are known for their exaggerated light responses, the molecules accumulated are likely to be antioxidants, recruited to deal with light and others stresses. Further phenotypes displayed by hp mutations are reduced growth and an apparent disturbance in water loss. Here, we examined the impact of the hp1 mutation and its near isogenic line cv Micro-Tom (MT) on stomatal conductance (gs), transpiration (E), CO(2) assimilation (A) and water use efficiency (WUE). Detached hp1 leaves lost water more rapidly than control leaves, but this behaviour was reversed by exogenous abscisic acid (ABA), indicating the ability of hp1 to respond to this hormone. Although attached hp1 leaves had enhanced gs, E and A compared to control leaves, genotypic differences were lost when water was withheld. Both instantaneous leaf-level WUE and long-term whole plant WUE did not differ between hp1 and MT. Our results indicate a link between exaggerated light response and water loss in hp1, which has important implications for the use of this mutant in both basic and horticultural research. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

The SOS response increases bacterial fitness, but not evolvability, under a sublethal dose of antibiotic.

Science.gov (United States)

Torres-Barceló, Clara; Kojadinovic, Mila; Moxon, Richard; MacLean, R Craig

2015-10-07

Exposure to antibiotics induces the expression of mutagenic bacterial stress-response pathways, but the evolutionary benefits of these responses remain unclear. One possibility is that stress-response pathways provide a short-term advantage by protecting bacteria against the toxic effects of antibiotics. Second, it is possible that stress-induced mutagenesis provides a long-term advantage by accelerating the evolution of resistance. Here, we directly measure the contribution of the Pseudomonas aeruginosa SOS pathway to bacterial fitness and evolvability in the presence of sublethal doses of ciprofloxacin. Using short-term competition experiments, we demonstrate that the SOS pathway increases competitive fitness in the presence of ciprofloxacin. Continued exposure to ciprofloxacin results in the rapid evolution of increased fitness and antibiotic resistance, but we find no evidence that SOS-induced mutagenesis accelerates the rate of adaptation to ciprofloxacin during a 200 generation selection experiment. Intriguingly, we find that the expression of the SOS pathway decreases during adaptation to ciprofloxacin, and this helps to explain why this pathway does not increase long-term evolvability. Furthermore, we argue that the SOS pathway fails to accelerate adaptation to ciprofloxacin because the modest increase in the mutation rate associated with SOS mutagenesis is offset by a decrease in the effective strength of selection for increased resistance at a population level. Our findings suggest that the primary evolutionary benefit of the SOS response is to increase bacterial competitive ability, and that stress-induced mutagenesis is an unwanted side effect, and not a selected attribute, of this pathway. © 2015 The Authors.

SOS score: an optimized score to screen acute stroke patients for obstructive sleep apnea.

Science.gov (United States)

Camilo, Millene R; Sander, Heidi H; Eckeli, Alan L; Fernandes, Regina M F; Dos Santos-Pontelli, Taiza E G; Leite, Joao P; Pontes-Neto, Octavio M

2014-09-01

Obstructive sleep apnea (OSA) is frequent in acute stroke patients, and has been associated with higher mortality and worse prognosis. Polysomnography (PSG) is the gold standard diagnostic method for OSA, but it is impracticable as a routine for all acute stroke patients. We evaluated the accuracy of two OSA screening tools, the Berlin Questionnaire (BQ), and the Epworth Sleepiness Scale (ESS) when administered to relatives of acute stroke patients; we also compared these tools against a combined screening score (SOS score). Ischemic stroke patients were submitted to a full PSG at the first night after onset of symptoms. OSA severity was measured by apnea-hypopnea index (AHI). BQ and ESS were administered to relatives of stroke patients before the PSG and compared to SOS score for accuracy and C-statistics. We prospectively studied 39 patients. OSA (AHI ≥10/h) was present in 76.9%. The SOS score [area under the curve (AUC): 0.812; P = 0.005] and ESS (AUC: 0.789; P = 0.009) had good predictive value for OSA. The SOS score was the only tool with significant predictive value (AUC: 0.686; P = 0.048) for severe OSA (AHI ≥30/h), when compared to ESS (P = 0.119) and BQ (P = 0.191). The threshold of SOS ≤10 showed high sensitivity (90%) and negative predictive value (96.2%) for OSA; SOS ≥20 showed high specificity (100%) and positive predictive value (92.5%) for severe OSA. The SOS score administered to relatives of stroke patients is a useful tool to screen for OSA and may decrease the need for PSG in acute stroke setting. Copyright © 2014 Elsevier B.V. All rights reserved.

Azospirillum brasilense and Azospirillum lipoferum Hydrolyze Conjugates of GA20 and Metabolize the Resultant Aglycones to GA1 in Seedlings of Rice Dwarf Mutants1

Science.gov (United States)

Cassán, Fabricio; Bottini, Rubén; Schneider, Gernot; Piccoli, Patricia

2001-01-01

Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17- 2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3β-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant. PMID:11299384

SOS Children's Friendly Community Historical Overview

Science.gov (United States)

Lukaš, Mirko; Lenard, Ivan

2014-01-01

SOS Children's Village Croatia is categorized as a children's home whose primary goal is taking care of children without an adequate parental care or parents themselves. Moreover, it aims at providing children, regardless of their racial, national or religious affiliation, with affection and love in a safe family environment. In addition, SOS…

Study on the early and late mutants of radiation induced rice

International Nuclear Information System (INIS)

Yang Hefeng; Chen Xiulan; He Zhentian; Gu Shiliang; Xu Chenwu

1990-12-01

After three years of consecutive experiments for the irradiated M 2 generations of 53 different varieties of rice, the following results have been obtained: (1) The average of early mutant plant rate is 1.4%. The rate in the early-maturing varieties is lower than that in the late-maturing varieties. It is in proportion to the length of growing period of these varieties tested. The shortened days of growing period of early mutants are 3 to 32 days (the average was 9.5 days), and it is increasing as the growing period increases. (2) In the irradiated M 2 generation of same variety, the early mutants and late mutants could be simultaneously happened, but the rate of the late mutants is 2.67%, which is higher than the rate of early mutants (1.39%). The shortened and prolonged days of growing period are 11.5 and 10.5 days respectively. These early and late mutants have some changes, both good and bad, in agronomical traits such as plant height, weight per kilo-grains and grains number per tassel. In some extent these changes are significant

The application of shortened upper leaf mutant in barley breeding

International Nuclear Information System (INIS)

Jin Hua

2004-01-01

The shortened upper leaf mutant was induced from Fuji Nigo by γ-ray irradiation. Fuji Nigo, the mutant, cross-cut F 1 , F 2 and back-cross F 1 , F 2 were used to analyze mutant heredity by comparative study. The yield, chlorophyll content, light intensity, dry matter of mutant were investigated. The results showed that (1) the mutant character was controlled by a couple of nuclear genes which were partial dominance; (2) the transmittance of the mutant colony was better than that of Fuji Nigo and bottom dry matter was much more than that of Fuji Nigo; (3) under the condition of high fertilizer and high plant population , the yield of mutant was higher than that of Fuji Nigo; (4) the content of chlorophyll a in the mutant was higher than that in Fuji Nigo

The Arabidopsis aba4-1 mutant reveals a specific function for neoxanthin in protection against photooxidative stress.

Science.gov (United States)

Dall'Osto, Luca; Cazzaniga, Stefano; North, Helen; Marion-Poll, Annie; Bassi, Roberto

2007-03-01

The aba4-1 mutant completely lacks neoxanthin but retains all other xanthophyll species. The missing neoxanthin in light-harvesting complex (Lhc) proteins is compensated for by higher levels of violaxanthin, albeit with lower capacity for photoprotection compared with proteins with wild-type levels of neoxanthin. Detached leaves of aba4-1 were more sensitive to oxidative stress than the wild type when exposed to high light and incubated in a solution of photosensitizer agents. Both treatments caused more rapid pigment bleaching and lipid oxidation in aba4-1 than wild-type plants, suggesting that neoxanthin acts as an antioxidant within the photosystem II (PSII) supercomplex in thylakoids. While neoxanthin-depleted Lhc proteins and leaves had similar sensitivity as the wild type to hydrogen peroxide and singlet oxygen, they were more sensitive to superoxide anions. aba4-1 intact plants were not more sensitive than the wild type to high-light stress, indicating the existence of compensatory mechanisms of photoprotection involving the accumulation of zeaxanthin. However, the aba4-1 npq1 double mutant, lacking zeaxanthin and neoxanthin, underwent stronger PSII photoinhibition and more extensive oxidation of pigments than the npq1 mutant, which still contains neoxanthin. We conclude that neoxanthin preserves PSII from photoinactivation and protects membrane lipids from photooxidation by reactive oxygen species. Neoxanthin appears particularly active against superoxide anions produced by the Mehler's reaction, whose rate is known to be enhanced in abiotic stress conditions.

Genetic and agronomic evaluation of induced semi-dwarf mutants of rice

International Nuclear Information System (INIS)

Rutger, J.N.

1984-01-01

Induced semi-dwarf mutants have played an important role in California's rapid shift from nearly all tall rice varieties in 1978 to nearly all semi-dwarf varieties at present. In 1981 over half of the California rice area was planted with semi-dwarf varieties carrying the induced mutant semi-dwarfing gene sd 1 , while much of the other half was planted to a variety deriving its semi-dwarfism from IR8. The sd 1 mutant is allelic to the major semi-dwarfing gene in DGWG and IR8. Current objectives are to determine the inheritance of new semi-dwarf mutants, including allelism tests with sd 1 , and to evaluate the agronomic potential of nonallelic sources and of double-dwarfs. To date semi-dwarf mutants from 10 varieties have been partially or completely evaluated. At least three nonallelic semi-dwarfing genes, sd 1 , sd 2 , and sd 4 , have been described. Rather than attempt to determine all possible allelic relationships of new mutants, crosses are being made only to the reference sd 1 source, since sd 1 , still seems to be the most productive semi-dwarfing gene source. However, nonallelic semi-dwarf mutants in the varieties M5 and Labelle may be useful if genetic vulnerability from widespread usage of the sd 1 source becomes a problem. (author)

Mutant lines of currant tomato, valuable germplasm with multiple disease resistance

International Nuclear Information System (INIS)

Govorova, G.F.; Khrustaleva, V.V.; Shcherbakov, V.K.

1987-01-01

Studies were carried out for two years on eight mutant lines of currant tomato at the Krymsk Experimental Breeding Station of the N.I. Vavilov All-Union Scientific Research Institute of Plant-Growing (VIR). The station is situated in an area of commercial field tomato growing (Krasnodar region). The mutant lines of currant tomato (VIR specimen No. k-4053) were obtained through chronic gamma-irradiation. A disease resistance evaluation of the mutants was carried out for Verticillium wilt (Verticillium albo-atrum Rein. and Berth.), for black bacterial spotting (Xanthomonas vesicatoria Dows.), for tobacco mosaic virus Nicotiana 1 Smith), for streak virus (Nicotiana 1), for the combination TMV with X and Y potato viruses, for cucumber virus (Cucumis 1), and also for top rot. Fifty plants of each mutant line were evaluated and checks were made three times in each season. A comparison of the currant tomato mutants with the standard tomato varieties demonstrates the better resistance shown by the mutant germplasm to the main pathogens. The degree to which some currant tomato mutants were affected by Verticillium was lower than that of the most VerticiIlium-resistant samples of tomato evaluated between 1975 and 1981. The mutants of currant tomato should therefore be of interest as germplasm in breeding tomatoes for improved multiple disease resistance

Gamma ray irradiation to roots of tea-plants and induced mutant system

International Nuclear Information System (INIS)

Takeda, Yoshiyuki; Nekaku, Koji; Wada, Mitsumasa

1990-01-01

In order to utilize the useful mutation which is induced by irradiation for the breeding of tea-plants, the gamma-ray irradiation to the roots of tea-plants was carried out. The samples were the roots of tea-plants of four varieties dug up in February, 1984, and were adjusted to about 20 cm, then, put in the cold storage at 5degC for 9 months till the time of irradiation in November, 1984. However, a part of them was taken out in August, and planted in a field for 76 days to germinate, thereafter, used as the samples. The gamma-ray from a Co-60 source was irradiated in the radiation breeding laboratory of Agriculture Bioresources Research Institute at the total dose of 1, 2 and 3 kR and the dose rate of 500 R/h. The irradiated roots were planted as they are or in the state of being cut, and the rate of germination, the number of buds and the induced mutation were examined. Clear difference was not observed in the rate of germination and the number of buds between the irradiated samples and those without irradiation. The long roots were superior to the short roots regarding these items. The types of the induced mutation were mostly thin leaves, and also yellowing, mottling, fascination and so on occurred. The mutant system lacking trichomes on the back of new leaves is considered to be strong against tea anthracnose, and is valuable. (K.I.)

Gamma ray irradiation to roots of tea-plants and induced mutant system

Energy Technology Data Exchange (ETDEWEB)

Takeda, Yoshiyuki; Nekaku, Koji; Wada, Mitsumasa (National Research Inst. of Vegetables, Ornamental Plants and Tea, Ano, Mie (Japan))

1990-11-01

In order to utilize the useful mutation which is induced by irradiation for the breeding of tea-plants, the gamma-ray irradiation to the roots of tea-plants was carried out. The samples were the roots of tea-plants of four varieties dug up in February, 1984, and were adjusted to about 20 cm, then, put in the cold storage at 5degC for 9 months till the time of irradiation in November, 1984. However, a part of them was taken out in August, and planted in a field for 76 days to germinate, thereafter, used as the samples. The gamma-ray from a Co-60 source was irradiated in the radiation breeding laboratory of Agriculture Bioresources Research Institute at the total dose of 1, 2 and 3 kR and the dose rate of 500 R/h. The irradiated roots were planted as they are or in the state of being cut, and the rate of germination, the number of buds and the induced mutation were examined. Clear difference was not observed in the rate of germination and the number of buds between the irradiated samples and those without irradiation. The long roots were superior to the short roots regarding these items. The types of the induced mutation were mostly thin leaves, and also yellowing, mottling, fascination and so on occurred. The mutant system lacking trichomes on the back of new leaves is considered to be strong against tea anthracnose, and is valuable. (K.I.).

Atomic orbital-based SOS-MP2 with tensor hypercontraction. II. Local tensor hypercontraction

Science.gov (United States)

Song, Chenchen; Martínez, Todd J.

2017-01-01

In the first paper of the series [Paper I, C. Song and T. J. Martinez, J. Chem. Phys. 144, 174111 (2016)], we showed how tensor-hypercontracted (THC) SOS-MP2 could be accelerated by exploiting sparsity in the atomic orbitals and using graphical processing units (GPUs). This reduced the formal scaling of the SOS-MP2 energy calculation to cubic with respect to system size. The computational bottleneck then becomes the THC metric matrix inversion, which scales cubically with a large prefactor. In this work, the local THC approximation is proposed to reduce the computational cost of inverting the THC metric matrix to linear scaling with respect to molecular size. By doing so, we have removed the primary bottleneck to THC-SOS-MP2 calculations on large molecules with O(1000) atoms. The errors introduced by the local THC approximation are less than 0.6 kcal/mol for molecules with up to 200 atoms and 3300 basis functions. Together with the graphical processing unit techniques and locality-exploiting approaches introduced in previous work, the scaled opposite spin MP2 (SOS-MP2) calculations exhibit O(N2.5) scaling in practice up to 10 000 basis functions. The new algorithms make it feasible to carry out SOS-MP2 calculations on small proteins like ubiquitin (1231 atoms/10 294 atomic basis functions) on a single node in less than a day.

Onderzoek naar de toepasbaarheid van SOS-chromotest

NARCIS (Netherlands)

Voogd CE; van der Stel JJ; Verharen HW; van Bruchem MC

1988-01-01

Met 35 stoffen werd de mutagene activiteit onderzocht met een SOS-chromotest kit, de Ames-test en de fluctuatietest met Klebsiella pneumoniae. Voorzover het alkylerende stoffen betreft die basenpaar substituties veroorzaken, blijkt er een goede overeenstemming te bestaan met de resultaten van

A Single Recessive Mutated Gene (Sd237-1) Controlling Semi-Dwarf Plant Stature of Rice

International Nuclear Information System (INIS)

Sobrizal

2009-01-01

Dwarfism is a valuable trait in crop breeding, because it increases lodging resistance and decreases damages due to wind and rain. During the course of this study, a semi-dwarf mutant was successfully induced through 200 Gy gamma ray irradiated KI 237 seeds. KI 237 is a pure line with high yield potency, developed through an Indica-Japonica cross of IR36 / Koshihikari. The selected semi-dwarf plant reached 60 - 62 % of plant height of original plant KI 237 at the mature stage. The length of inter nodes, panicle, and seed were also compared between these two plants. The retardation of the 1 st (uppermost) inter nodes was 24 %, moreover, the retardation of panicle and seed length were only 10 % and 2 %, respectively. The elongation pattern of the inter nodes in this mutant was almost the same as sd1 (Dee-geo-woo-gen), the original parent of the first release modern rice variety, but their performances were different. Based on the segregation analysis in M 2 and M 3 generation it was concluded that this mutant was controlled by a single recessive mutated gene. This gene was designated as sd 237-1 . This mutant should be useful as a genetic resource for the improvement of KI 237 line through back-cross breeding as well as be developed further in breeding program directly to be a new high yielding mutant variety. (author)

The Arabidopsis szl1 Mutant Reveals a Critical Role of β-Carotene in Photosystem I Photoprotection1[C][W

Science.gov (United States)

Cazzaniga, Stefano; Li, Zhirong; Niyogi, Krishna K.; Bassi, Roberto; Dall’Osto, Luca

2012-01-01

Carotenes and their oxygenated derivatives, the xanthophylls, are structural determinants in both photosystems (PS) I and II. They bind and stabilize photosynthetic complexes, increase the light-harvesting capacity of chlorophyll-binding proteins, and have a major role in chloroplast photoprotection. Localization of carotenoid species within each PS is highly conserved: Core complexes bind carotenes, whereas peripheral light-harvesting systems bind xanthophylls. The specific functional role of each xanthophyll species has been recently described by genetic dissection, however the in vivo role of carotenes has not been similarly defined. Here, we have analyzed the function of carotenes in photosynthesis and photoprotection, distinct from that of xanthophylls, by characterizing the suppressor of zeaxanthin-less (szl) mutant of Arabidopsis (Arabidopsis thaliana) which, due to the decreased activity of the lycopene-β-cyclase, shows a lower carotene content than wild-type plants. When grown at room temperature, mutant plants showed a lower content in PSI light-harvesting complex I complex than the wild type, and a reduced capacity for chlorophyll fluorescence quenching, the rapidly reversible component of nonphotochemical quenching. When exposed to high light at chilling temperature, szl1 plants showed stronger photoxidation than wild-type plants. Both PSI and PSII from szl1 were similarly depleted in carotenes and yet PSI activity was more sensitive to light stress than PSII as shown by the stronger photoinhibition of PSI and increased rate of singlet oxygen release from isolated PSI light-harvesting complex I complexes of szl1 compared with the wild type. We conclude that carotene depletion in the core complexes impairs photoprotection of both PS under high light at chilling temperature, with PSI being far more affected than PSII. PMID:23029671

DNA compaction in the early part of the SOS response is dependent on RecN and RecA.

Science.gov (United States)

Odsbu, Ingvild; Skarstad, Kirsten

2014-05-01

The nucleoids of undamaged Escherichia coli cells have a characteristic shape and number, which is dependent on the growth medium. Upon induction of the SOS response by a low dose of UV irradiation an extensive reorganization of the nucleoids occurred. Two distinct phases were observed by fluorescence microscopy. First, the nucleoids were found to change shape and fuse into compact structures at midcell. The compaction of the nucleoids lasted for 10-20 min and was followed by a phase where the DNA was dispersed throughout the cells. This second phase lasted for ~1 h. The compaction was found to be dependent on the recombination proteins RecA, RecO and RecR as well as the SOS-inducible, SMC (structural maintenance of chromosomes)-like protein RecN. RecN protein is produced in high amounts during the first part of the SOS response. It is possible that the RecN-mediated 'compact DNA' stage at the beginning of the SOS response serves to stabilize damaged DNA prior to recombination and repair.

Influence of the gene xthA in the activation of SOS response of Escherichia coli

International Nuclear Information System (INIS)

Dominguez M, V.

2013-01-01

The SOS response is one of the strategies that has Escherichia coli to counteract the lesions in the genetic material. The response is integrated for approximately 60 genes that when are activated they provide to the cell a bigger opportunity to survive. For the activation of this system is necessary that DNA regions of simple chain are generated, in such a way that most of the lesions should be processed, to be able to induce this answer. Some genes that intervene in this procedure, as recO, recB and recJ are recognized since when being exposed to the radiation, their activity SOS is smaller than in a wild strain. In previous works has been studied that to inactivate the genes that are involves in the lesions processing to generate DNA of simple chain, the SOS induction level diminishes with regard to a wild strain, but that when eliminating the genes that are involves directly in the repair, the SOS response increases. In this work a strain with defects in the gene xthA was built, which encodes for an endonuclease AP that participates in the repair mechanism by base excision and was evaluated their sensibility as the activity of the SOS response when exposing it to UV light and gamma radiation. The results showed that the lethality of the strain with the defect is very similar to the wild strain; while the activation level of the SOS response is bigger in comparison with the wild strain when being exposed to UV light; suggesting the existence of an enzyme that recognizes the lesions that produces this radiation, however, is not this the main repair channel, since the survival is similar to that of the wild strain. On the contrary, the results obtained with gamma radiation showed that the lethality diminishes in comparison to that of the wild strain, like the SOS activity; due surely to that the gene product intervenes in the repair for base excision, participating in the formation of the previous substrate to the activation of the SOS response. (Author)

Mechanism of SOS PR-domain autoinhibition revealed by single-molecule assays on native protein from lysate.

Science.gov (United States)

Lee, Young Kwang; Low-Nam, Shalini T; Chung, Jean K; Hansen, Scott D; Lam, Hiu Yue Monatrice; Alvarez, Steven; Groves, Jay T

2017-04-28

The guanine nucleotide exchange factor (GEF) Son of Sevenless (SOS) plays a critical role in signal transduction by activating Ras. Here we introduce a single-molecule assay in which individual SOS molecules are captured from raw cell lysate using Ras-functionalized supported membrane microarrays. This enables characterization of the full-length SOS protein, which has not previously been studied in reconstitution due to difficulties in purification. Our measurements on the full-length protein reveal a distinct role of the C-terminal proline-rich (PR) domain to obstruct the engagement of allosteric Ras independently of the well-known N-terminal domain autoinhibition. This inhibitory role of the PR domain limits Grb2-independent recruitment of SOS to the membrane through binding of Ras·GTP in the SOS allosteric binding site. More generally, this assay strategy enables characterization of the functional behaviour of GEFs with single-molecule precision but without the need for purification.

The effect of altered dosage of a mutant allele of Teosinte branched 1 (tb1-ref) on the root system of modern maize.

Science.gov (United States)

Gaudin, Amelie C M; McClymont, Sarah A; Soliman, Sameh S M; Raizada, Manish N

2014-02-14

There was ancient human selection on the wild progenitor of modern maize, Balsas teosinte, for decreased shoot branching (tillering), in order to allow more nutrients to be diverted to grain. Mechanistically, the decline in shoot tillering has been associated with selection for increased expression of the major domestication gene Teosinte Branched 1 (Tb1) in shoot primordia. Therefore, TB1 has been defined as a repressor of shoot branching. It is known that plants respond to changes in shoot size by compensatory changes in root growth and architecture. However, it has not been reported whether altered TB1 expression affects any plant traits below ground. Previously, changes in dosage of a well-studied mutant allele of Tb1 in modern maize, called tb1-ref, from one to two copies, was shown to increase tillering. As a result, plants with two copies of the tb1-ref allele have a larger shoot biomass than heterozygotes. Here we used aeroponics to phenotype the effects of tb1-ref copy number on maize roots at macro-, meso- and micro scales of development. An increase in the tb1-ref copy number from one to two copies resulted in: (1) an increase in crown root number due to the cumulative initiation of crown roots from successive tillers; (2) higher density of first and second order lateral roots; and (3) reduced average lateral root length. The resulting increase in root system biomass in homozygous tb1-ref mutants balanced the increase in shoot biomass caused by enhanced tillering. These changes caused homozygous tb1-ref mutants of modern maize to more closely resemble its ancestor Balsas teosinte below ground. We conclude that a decrease in TB1 function in maize results in a larger root system, due to an increase in the number of crown roots and lateral roots. Given that decreased TB1 expression results in a more highly branched and larger shoot, the impact of TB1 below ground may be direct or indirect. We discuss the potential implications of these findings for whole

SOS System Induction Inhibits the Assembly of Chemoreceptor Signaling Clusters in Salmonella enterica.

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Irazoki, Oihane; Mayola, Albert; Campoy, Susana; Barbé, Jordi

2016-01-01

Swarming, a flagellar-driven multicellular form of motility, is associated with bacterial virulence and increased antibiotic resistance. In this work we demonstrate that activation of the SOS response reversibly inhibits swarming motility by preventing the assembly of chemoreceptor-signaling polar arrays. We also show that an increase in the concentration of the RecA protein, generated by SOS system activation, rather than another function of this genetic network impairs chemoreceptor polar cluster formation. Our data provide evidence that the molecular balance between RecA and CheW proteins is crucial to allow polar cluster formation in Salmonella enterica cells. Thus, activation of the SOS response by the presence of a DNA-injuring compound increases the RecA concentration, thereby disturbing the equilibrium between RecA and CheW and resulting in the cessation of swarming. Nevertheless, when the DNA-damage decreases and the SOS response is no longer activated, basal RecA levels and thus polar cluster assembly are reestablished. These results clearly show that bacterial populations moving over surfaces make use of specific mechanisms to avoid contact with DNA-damaging compounds.

Primary study on lesion mimic mutants of rice (oryza sativa L.)

International Nuclear Information System (INIS)

Hao Zhongna; Zhang Hongzhi; Tao Rongixang

2007-01-01

Nineteen lesion mimic mutants (xsl1-19) of japonica rice Xiushui11 were obtained by γ-rays irradiation treatment. All mutants belonged to whole life lesion mimic. Lesion mimic of mutants didn't largen after tillering stage, leaves didn't wither, and no effect on the plants exsert spikes and seed. When the highest temperature in day exceeded 32 degree C in seedling stage, lesion mimic of all mutant expect xsl19 disappeared. Under 32 degree C, lesion mimic would appear gradually, and symptoms weren't inhibited by high temperature after 5 leaf stage. The plant heights of all lesion mimic mutants were 47.56-63.54 cm in the tillering stage, and that of CK was 83.75 cm; but the dwarf phenomenon of mutants only appeared before tillering stage, and didn't affect plant heights finally; the heading dates of mutants were the same to the CK, the ear length of all mutants were 9.43-15.19 cm, and that of CK was 16.41 cm; the total grain quantity per spike of all mutants were 88.17-165.33, and those of xsl19 and CK were 49.50 and 76.17. The results showed all lesion mimic mutants except xsl19 had short spikes and total grain quantity per spike increasing. All lesion mimic mutants were susceptible to Magnaporthe grisea, and they had no relationship with resistance. (authors)

Endovascular stentectomy using the snare over stent-retriever (SOS technique: An experimental feasibility study.

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Tareq Meyer

Full Text Available Feasibility of endovascular stentectomy using a snare over stent-retriever (SOS technique was evaluated in a silicon flow model and an in vivo swine model. In vitro, stentectomy of different intracranial stents using the SOS technique was feasible in 22 out of 24 (92% retrieval maneuvers. In vivo, stentectomy was successful in 10 out of 10 procedures (100%. In one case self-limiting vasospasm was observed angiographically as a technique related complication in the animal model. Endovascular stentectomy using the SOS technique is feasible in an experimental setting and may be transferred to a clinical scenario.

Photosystem II repair and plant immunity: Lessons learned from Arabidopsis mutant lacking the THYLAKOID LUMEN PROTEIN 18.3

Directory of Open Access Journals (Sweden)

Sari eJärvi

2016-03-01

Full Text Available Chloroplasts play an important role in the cellular sensing of abiotic and biotic stress. Signals originating from photosynthetic light reactions, in the form of redox and pH changes, accumulation of reactive oxygen and electrophile species or stromal metabolites are of key importance in chloroplast retrograde signaling. These signals initiate plant acclimation responses to both abiotic and biotic stresses. To reveal the molecular responses activated by rapid fluctuations in growth light intensity, gene expression analysis was performed with Arabidopsis thaliana wild type and the tlp18.3 mutant plants, the latter showing a stunted growth phenotype under fluctuating light conditions (Biochem. J, 406, 415-425. Expression pattern of genes encoding components of the photosynthetic electron transfer chain did not differ between fluctuating and constant light conditions, neither in wild type nor in tlp18.3 plants, and the composition of the thylakoid membrane protein complexes likewise remained unchanged. Nevertheless, the fluctuating light conditions repressed in wild-type plants a broad spectrum of genes involved in immune responses, which likely resulted from shade-avoidance responses and their intermixing with hormonal signaling. On the contrary, in the tlp18.3 mutant plants there was an imperfect repression of defense-related transcripts upon growth under fluctuating light, possibly by signals originating from minor malfunction of the photosystem II (PSII repair cycle, which directly or indirectly modulated the transcript abundances of genes related to light perception via phytochromes. Consequently, a strong allocation of resources to defense reactions in the tlp18.3 mutant plants presumably results in the stunted growth phenotype under fluctuating light.

Sos - response induction by gamma radiation in Escherichia coli strains with different repair capacities

International Nuclear Information System (INIS)

Serment Guerrero, J.H.

1992-01-01

The Sos - response in Escherichia coli is formed by several genes involved in mechanisms of tolerance and/or repair, and only activates when a DNA - damage appears. It is controlled by recA and lexA genes. In normal circumstances, LexA protein is linked in every Sos operators, blocking the transcription. When a DNA damage occurs, a Sos signal is generated, Rec A protein changes its normal functions, starts acting as a protease and cleaves Lex A, allowing the transcription of all Sos genes. This response can be quantified by means of Sos Chromo test, performed by Quillardet and Ofnung (1985). In using the Chromo test, it has been observed that the DNA damage made by gamma radiation in Escherichia coli depends on both the doses and the doses rate. It has been shown that the exposure of Escherichia coli PQ37 strain (uvrA) to low doses at low dose rate appears to retard the response, suggesting the action of a repair mechanism. (Brena 1990). In this work, we compare the response in Escherichia coli strains deficient in different mechanisms of repair and/or tolerance. It is observed the importance of rec N gene in the repair of DNA damage produced by gamma radiation. (Author)

77 FR 65896 - Award of a Single-Source Replacement Grant to SOS Children's Villages Illinois in Chicago, IL

Science.gov (United States)

2012-10-31

....623] Award of a Single-Source Replacement Grant to SOS Children's Villages Illinois in Chicago, IL... (FYSB) announces the award of a single-source replacement grant to SOS Children's Villages Illinois in... grant. ACYF/FYSB has designated SOS Children's Villages Illinois, a 501(c)(3) non-profit organization...

Repair promoted by plasmid pKM101 is different from SOS repair

International Nuclear Information System (INIS)

Goze, A.; Devoret, R.

1979-01-01

In E. coli K12 bacteria carrying plasmid pKM101, prophage lambda was induced at UV doses higher than in plasmid-less parental bacteria. UV-induced reactivation per se was less effective. Bacteria with pKM101 showed no alteration in their division cycle. Plasmid PKM101 coded for a constitutive error-prone repair different from the inducible error-prone repair called SOS repair. Plasmid pKM101 protected E. coli bacteria from UV damage but slightly sensitized them to X-ray lesions. Protection against UV damage was effective in mutant bacteria deficient in DNA excision-repair provided that the recA, lexA and uvrE genes were functional. Survival of phages lambda and S13 after UV irradiation was enhanced in bacteria carrying plasmid pKM101; phage lambda mutagenesis was also increased. Plasmid pKM101 repaired potentially lethal DNA lesions, although Wild-type DNA sequences may not necessarily be restored; hence the mutations observed are the traces of the original DNA lesions. (Auth.)

Characteristic, inheritance and breeding application of rice mutants with greenable albino leaf

International Nuclear Information System (INIS)

Fang Xiantao; Ma Hongli; Zhao Fuyuan; Zhang Qingqi; Zhang Shubiao

2009-01-01

Inheritance and main agronomic traits of photo-thermo-sensitive genic male sterile line with green-revertible albino leaf were investigated. The results indicated that the mutants might be divided into three types: albino regreening type (W2, W3, W4 and W10), albino to kelly type (W9) and abino-regreening-albino-regreening type (W1 and W7). Genetic study indicated that green-revertible albino leaf color trait of the mutants as controlled by a single recessive gene. These mutants had similar agronomic traits and fertility characteristics to the corresponding male sterile line 'Peiai 64S'. The hybrids of these mutants had similar characteristics with original-hybrids in plant type, developing of tillers and plant height. The yield components of the mutant hybrids were different depending on different mutants. The yield potential of hybrids of W1, W2 and W3 were similar to the original-hybrid. The results also indicated that W1, W2 and W3 had breeding application value. (authors)

Gene expression profile analysis of Ligon lintless-1 (Li1) mutant reveals important genes and pathways in cotton leaf and fiber development.

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Ding, Mingquan; Jiang, Yurong; Cao, Yuefen; Lin, Lifeng; He, Shae; Zhou, Wei; Rong, Junkang

2014-02-10

Ligon lintless-1 (Li1) is a monogenic dominant mutant of Gossypium hirsutum (upland cotton) with a phenotype of impaired vegetative growth and short lint fibers. Despite years of research involving genetic mapping and gene expression profile analysis of Li1 mutant ovule tissues, the gene remains uncloned and the underlying pathway of cotton fiber elongation is still unclear. In this study, we report the whole genome-level deep-sequencing analysis of leaf tissues of the Li1 mutant. Differentially expressed genes in leaf tissues of mutant versus wild-type (WT) plants are identified, and the underlying pathways and potential genes that control leaf and fiber development are inferred. The results show that transcription factors AS2, YABBY5, and KANDI-like are significantly differentially expressed in mutant tissues compared with WT ones. Interestingly, several fiber development-related genes are found in the downregulated gene list of the mutant leaf transcriptome. These genes include heat shock protein family, cytoskeleton arrangement, cell wall synthesis, energy, H2O2 metabolism-related genes, and WRKY transcription factors. This finding suggests that the genes are involved in leaf morphology determination and fiber elongation. The expression data are also compared with the previously published microarray data of Li1 ovule tissues. Comparative analysis of the ovule transcriptomes of Li1 and WT reveals that a number of pathways important for fiber elongation are enriched in the downregulated gene list at different fiber development stages (0, 6, 9, 12, 15, 18dpa). Differentially expressed genes identified in both leaf and fiber samples are aligned with cotton whole genome sequences and combined with the genetic fine mapping results to identify a list of candidate genes for Li1. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of the SOS response on the mean fitness of unicellular populations: a quasispecies approach.

Science.gov (United States)

Kama, Amit; Tannenbaum, Emmanuel

2010-11-30

The goal of this paper is to develop a mathematical model that analyzes the selective advantage of the SOS response in unicellular organisms. To this end, this paper develops a quasispecies model that incorporates the SOS response. We consider a unicellular, asexually replicating population of organisms, whose genomes consist of a single, double-stranded DNA molecule, i.e. one chromosome. We assume that repair of post-replication mismatched base-pairs occurs with probability , and that the SOS response is triggered when the total number of mismatched base-pairs is at least . We further assume that the per-mismatch SOS elimination rate is characterized by a first-order rate constant . For a single fitness peak landscape where the master genome can sustain up to mismatches and remain viable, this model is analytically solvable in the limit of infinite sequence length. The results, which are confirmed by stochastic simulations, indicate that the SOS response does indeed confer a fitness advantage to a population, provided that it is only activated when DNA damage is so extensive that a cell will die if it does not attempt to repair its DNA.

The Arabidopsis aba4-1 Mutant Reveals a Specific Function for Neoxanthin in Protection against Photooxidative Stress[W

Science.gov (United States)

Dall'Osto, Luca; Cazzaniga, Stefano; North, Helen; Marion-Poll, Annie; Bassi, Roberto

2007-01-01

The aba4-1 mutant completely lacks neoxanthin but retains all other xanthophyll species. The missing neoxanthin in light-harvesting complex (Lhc) proteins is compensated for by higher levels of violaxanthin, albeit with lower capacity for photoprotection compared with proteins with wild-type levels of neoxanthin. Detached leaves of aba4-1 were more sensitive to oxidative stress than the wild type when exposed to high light and incubated in a solution of photosensitizer agents. Both treatments caused more rapid pigment bleaching and lipid oxidation in aba4-1 than wild-type plants, suggesting that neoxanthin acts as an antioxidant within the photosystem II (PSII) supercomplex in thylakoids. While neoxanthin-depleted Lhc proteins and leaves had similar sensitivity as the wild type to hydrogen peroxide and singlet oxygen, they were more sensitive to superoxide anions. aba4-1 intact plants were not more sensitive than the wild type to high-light stress, indicating the existence of compensatory mechanisms of photoprotection involving the accumulation of zeaxanthin. However, the aba4-1 npq1 double mutant, lacking zeaxanthin and neoxanthin, underwent stronger PSII photoinhibition and more extensive oxidation of pigments than the npq1 mutant, which still contains neoxanthin. We conclude that neoxanthin preserves PSII from photoinactivation and protects membrane lipids from photooxidation by reactive oxygen species. Neoxanthin appears particularly active against superoxide anions produced by the Mehler's reaction, whose rate is known to be enhanced in abiotic stress conditions. PMID:17351115

Plant height revertants of Dominant Semidwarf mutant rice created by low-energy ion irradiation

Energy Technology Data Exchange (ETDEWEB)

Liu Binmei [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Yuejin [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: yjwu@ipp.ac.cn; Xu Xue; Song, M.; Zhao, M. [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Fu, X.D. [Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101 (China)

2008-04-15

Dominant Semidwarf mutant rice (Sdd) was obtained from its wild type (WT) by irradiation with a low-energy ion beam. Six tall revertants of Sdd were induced by irradiation. The revertants restored the plant height to that of WT plants. Investigation of the agronomic character and genetic analysis indicate that the revertants are similar to WT plants with putative different inherited mutations. The revertants were checked for DNA differences using the simple sequence repeat technique. Among 408 such primers used, only 2 primers detected mutation sites in the revertants, which provided the molecular evidence for the revertants induced from Sdd. This study indicates that ion irradiation may be used as a mutagen to create revertants for plant architecture studies and could be a new application.

Suppressive effects of coffee on the SOS responses induced by UV and chemical mutagens

International Nuclear Information System (INIS)

Obana, Hirotaka; Nakamura, Sei-ichi; Tanaka, Ryou-ichi

1986-01-01

SOS-inducing activity of UV or chemical mutagens was strongly suppressed by instant coffee in Salmonella typhimurium TA1535/pSK1002. As decaffeinated instant coffee showed a similarly strong suppressive effect, it would seem that caffeine, a known inhibitor of SOS responses, is not responsible for the effect observed. The suppression was also shown by freshly brewed coffee extracts. However, the suppression was absent in green coffee-bean extracts. These results suggest that coffee contains some substance(s) which, apart from caffeine, suppresses SOS-inducing activity of UV or chemical mutagens and that the suppressive substance(s) are produced by roasting coffee beans. (Auth.)

A chilling sensitive mutant of Arabidopsis with altered steryl-ester metabolism

International Nuclear Information System (INIS)

Hugly, S.; McCourt, P.; Somerville, C.; Browse, J.; Patterson, G.W.

1990-01-01

A chilling-sensitive mutant of Arabidopsis thaliana was isolated and subjected to genetic, physiological, and biochemical analysis. The chilling-sensitive nature of the mutant line is due to a single recessive nuclear mutation at a locus designated chs1. In contrast to wild-type plants, which are not adversely affected by low temperatures, the chs1 mutant is killed by several days of exposure to temperatures below 18 degree C. Following exposure to chilling temperatures, the mutant displays two common symptoms of chilling injury - leaf chlorosis and electrolyte leakage. In these respects, the physiological response of the mutant to low temperatures mimics the response observed in some naturally occurring chilling sensitive species. The biochemical basis of chilling sensitivity was explored by examining the pattern of incorporation of 14 CO 2 into soluble metabolites and lipids in wild-type and mutant plants. The only difference observed between the mutant and wild type was that following low temperature treatment, the mutant accumulated 10-fold more radioactivity in a specific class of neutral lipids which were identified by a variety of criteria to be steryl-esters. The accumulation of radioactivity in the steryl-ester fraction occurs 24 hours before there is any visible evidence of chilling injury

Multiple pathways for SOS-induced mutagenesis in Escherichia coli: An overexpression of dinB/dinP results in strongly enhancing mutagenesis in the absence of any exogenous treatment to damage DNA

Science.gov (United States)

Kim, Su-Ryang; Maenhaut-Michel, Geneviéve; Yamada, Masami; Yamamoto, Yoshihiro; Matsui, Keiko; Sofuni, Toshio; Nohmi, Takehiko; Ohmori, Haruo

1997-01-01

dinP is an Escherichia coli gene recently identified at 5.5 min of the genetic map, whose product shows a similarity in amino acid sequence to the E. coli UmuC protein involved in DNA damage-induced mutagenesis. In this paper we show that the gene is identical to dinB, an SOS gene previously localized near the lac locus at 8 min, the function of which was shown to be required for mutagenesis of nonirradiated λ phage infecting UV-preirradiated bacterial cells (termed λUTM for λ untargeted mutagenesis). A newly constructed dinP null mutant exhibited the same defect for λUTM as observed previously with a dinB::Mu mutant, and the defect was complemented by plasmids carrying dinP as the only intact bacterial gene. Furthermore, merely increasing the dinP gene expression, without UV irradiation or any other DNA-damaging treatment, resulted in a strong enhancement of mutagenesis in F′lac plasmids; at most, 800-fold increase in the G6-to-G5 change. The enhanced mutagenesis did not depend on recA, uvrA, or umuDC. Thus, our results establish that E. coli has at least two distinct pathways for SOS-induced mutagenesis: one dependent on umuDC and the other on dinB/P. PMID:9391106

Induction of Mutants in Durum Wheat

International Nuclear Information System (INIS)

AL-Ubaidi, M.; Ibrahim, I.; AL-Hadithi, A.

2002-01-01

This investigation presents a breeding program for induction and development of a new genotype of durum wheat, resistant to lodging with high yield, by irradiation durum wheat hybrids (F2) with gamma rays 100 Gy, during 1990-1997 cultivation seasons. This program involves: induction of variability, selection evaluation of the mutants at three locations: Twaitha (Baghdad) Latifya ( Babylon) and Swari (Kutt). All mutants showed resistance to lodging and there was a significant reduction in plant height. Mutant SIXIZ-22 surpassed other mutants and its origin in lodging resistance and plant height (83.5,82.8 and 89.4 cm) in the three locations at generation M5 and M6, respectively. Also, there were significant differences between mutant and their origin in the number of spikes/M 2 and grain yild during the two successive generation. On the other hand, mutant IZxCO-105 surpassed other mutants in the number of spikes/M 2 (231.8,242.3 and 292) and grain yield (4336,3376 and 5232 kg/ha) in all testing location, respectively . (authors) 14 refs., 4 tabs

Viral and cellular SOS-regulated motor proteins: dsDNA translocation mechanisms with divergent functions.

Science.gov (United States)

Wolfe, Annie; Phipps, Kara; Weitao, Tao

2014-01-01

DNA damage attacks on bacterial cells have been known to activate the SOS response, a transcriptional response affecting chromosome replication, DNA recombination and repair, cell division and prophage induction. All these functions require double-stranded (ds) DNA translocation by ASCE hexameric motors. This review seeks to delineate the structural and functional characteristics of the SOS response and the SOS-regulated DNA translocases FtsK and RuvB with the phi29 bacteriophage packaging motor gp16 ATPase as a prototype to study bacterial motors. While gp16 ATPase, cellular FtsK and RuvB are similarly comprised of hexameric rings encircling dsDNA and functioning as ATP-driven DNA translocases, they utilize different mechanisms to accomplish separate functions, suggesting a convergent evolution of these motors. The gp16 ATPase and FtsK use a novel revolution mechanism, generating a power stroke between subunits through an entropy-DNA affinity switch and pushing dsDNA inward without rotation of DNA and the motor, whereas RuvB seems to employ a rotation mechanism that remains to be further characterized. While FtsK and RuvB perform essential tasks during the SOS response, their roles may be far more significant as SOS response is involved in antibiotic-inducible bacterial vesiculation and biofilm formation as well as the perspective of the bacteria-cancer evolutionary interaction.

Yield potential of a radiation induced early-dwarf mutant in linseed

International Nuclear Information System (INIS)

Nayar, G.G.

1975-01-01

An early maturing dwarf mutant, TL-1 was isolated in the high yielding linseed (Linum usitatissimum L.) wariety Neelum following seed irradiation with 50 kR gamma rays. The yield components of the mutant have been evaluated for its productivity in the M 7 generation. TL-1 is compact and significantly short in height (41.8 +- 2.71 cm) as compared to Neelum (79.2 +- 3.08 cm). In flowering the mutant is 30 days earlier than the parent under Trombay conditions. TL-1 and Neelum did not differ significantly in their mean number of primary branches. Although the mean seed yield per plant is lower, in 1000 seed weight the mutant is markedly superior to the parent. The oil content in TL-1 is significantly higher by 3.5 percent points than Neelum and its oil is lighter in colour. By growing more plants per unit area with reduced spacing, the yield potential of TL-1 was considerably increased. The productivity of oil per hectare per day of TL-1 was higher than Neelum. (author)

Plant mutation reports. Vol. 1, No. 3, December 2007

International Nuclear Information System (INIS)

2007-12-01

This issue of the Plant Mutation Reports emphasises the recently concluded IAEA-RCA project on Mutant Multi-location Trial and Mutational Enhancement of genetic Diversity (RAS/5/040) which has developed 33 mutant varieties and dozens of promising mutant breeding lines with high yield potantial and/or improved agronomic characters, resistance and end user quality traits

The Arabidopsis thaliana mutant air1 implicates SOS3 in the regulation of anthocyanins under salt stress

KAUST Repository

Van Oosten, Michael James; Sharkhuu, Altanbadralt; Batelli, Giorgia; Bressan, Ray Anthony; Maggio, Albino

2013-01-01

The accumulation of anthocyanins in plants exposed to salt stress has been largely documented. However, the functional link and regulatory components underlying the biosynthesis of these molecules during exposure to stress are largely unknown. In a

Lack of mitochondrial thioredoxin o1 is compensated by antioxidant components under salinity in Arabidopsis thaliana plants.

Science.gov (United States)

Calderón, Aingeru; Sánchez-Guerrero, Antonio; Ortiz-Espín, Ana; Martínez-Alcalá, Isabel; Camejo, Daymi; Jiménez, Ana; Sevilla, Francisca

2018-02-15

In a changing environment, plants are able to acclimate to the new conditions by regulating their metabolism through the antioxidant and redox systems involved in the stress response. Here we studied a mitochondrial thioredoxin in wild type (WT) Arabidopis thaliana and two Attrxo1 mutant lines grown in the absence or presence of 100 mM NaCl. Compared to WT plants, no evident phenotype was observed in the mutant plants in control condition, although they had higher number of stomata, loss of water, nitric oxide and carbonyl protein contents as well as higher activity of superoxide dismutase (SOD) and catalase enzymes than WT plants. Under salinity, the mutants presented lower water loss and higher stomatal closure, H 2 O 2 and lipid peroxidation levels accompanied by higher enzymatic activity of catalase and the different SOD isoenzymes compared to WT plants. These inductions may collaborate in the maintenance of plant integrity and growth observed under saline conditions, possibly as a way to compensate the lack of TRXo1. We discuss the potential of TRXo1 to influence the development of the whole plant under saline conditions, which have great value for the agronomy of plants growing under unfavourable environment. This article is protected by copyright. All rights reserved.

Isoenzymes performance of some rice varieties and their mutants

International Nuclear Information System (INIS)

Winarno, Ermin; Suliwarno, Ambyah; Ismachin, M.

1992-01-01

Isoenzymes performance of some rice varieties and their mutants. Genetics studies on alcohol dehydrogenase, malic enzyme, peroxidase, acid phosphase, and aminopeptidase isoenzymes were carried out on several groups of rice varieties and their mutant lines. The first groups consisted of Atomita I, Pelita I/1, A227/5, Mudgo, TN-1, and IR-26. The second group was Cisadane variety and its five mutants, namely OBS 18, OBS 208, OBS 297, OBS 306, and OBS 330. The third group was mutants line 627-10-3 and its mutants, namely 1063, 1066, 1067, 1076, and 1090. Isoenzymes extracts of the rice leaves were fractionated using polyacrylamide gel disc electrophoresis. The pattern of acid phosphate isoenzyme shows the specific character of rice mutants susceptible to brown plant hopper biotype 1. The gene(s) controlling malic enzyme in Cisadane's mutants is (are) estimated more resistant toward gamma irradiation than gene(s) responsible for controlling the other enzymes. Generally, the isoenzymes zymograms show that gene(s) controlling the mutants enzyme have undergone mutation. This case is shown by the changes of Rm value, as well as the amount and intensity of mutants bands. (authors). 7 refs., 7 figs

Detection of early psychotic symptoms: Validation of the Spanish version of the "Symptom Onset in Schizophrenia (SOS) inventory".

Science.gov (United States)

Mezquida, Gisela; Cabrera, Bibiana; Martínez-Arán, Anabel; Vieta, Eduard; Bernardo, Miguel

2018-03-01

The period of subclinical signs that precedes the onset of psychosis is referred to as the prodrome or high-risk mental state. The "Symptom Onset in Schizophrenia (SOS) inventory" is an instrument to characterize and date the initial symptoms of a psychotic illness. The present study aims to provide reliability and validity data for clinical and research use of the Spanish version of the SOS. Thirty-six participants with a first-episode of psychosis meeting DSM-IV criteria for schizophrenia/schizoaffective/schizophreniform disorder were administered the translated SOS and other clinical assessments. The internal validity, intrarater and interrater reliability were studied. We found strong interrater reliability. To detect the presence/absence of prodromal symptoms, Kappa coefficients ranged between 0.8 and 0.7. Similarly, the raters obtained an excellent level of agreement regarding the onset of each symptom and the duration of symptoms until first treatment (intraclass correlation coefficients between 0.9 and 1.0). Cronbach's alpha was 0.9-1.0 for all the items. The interrater reliability and concurrent validity were also excellent in both cases. This study provides robust psychometric properties of the Spanish version of the SOS. The translated version is adequate in terms of good internal validity, intrarater and interrater reliability, and is as time-efficient as the original version. Copyright © 2017 Elsevier B.V. All rights reserved.

Sensor Data from the NERACOOS SOS Server, 2000-present

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Northeastern Regional Association of Coastal Ocean Observing Systems (NERACOOS) Sensor Observation Service (SOS) The OCEANS IE -- formally approved as an OGC...

Quantitative Proteomic Analysis of Staphylococcus aureus Treated With Punicalagin, a Natural Antibiotic From Pomegranate That Disrupts Iron Homeostasis and Induces SOS.

Science.gov (United States)

Cooper, Bret; Islam, Nazrul; Xu, Yunfeng; Beard, Hunter S; Garrett, Wesley M; Gu, Ganyu; Nou, Xiangwu

2018-05-01

Staphylococcus aureus, a bacterial, food-borne pathogen of humans, can contaminate raw fruits and vegetables. While physical and chemical methods are available to control S. aureus, scientists are searching for inhibitory phytochemicals from plants. One promising compound from pomegranate is punicalagin, a natural antibiotic. To get a broader understanding of the inhibitory effect of punicalagin on S. aureus growth, high-throughput mass spectrometry and quantitative isobaric labeling was used to investigate the proteome of S. aureus after exposure to a sublethal dose of punicalagin. Nearly half of the proteins encoded by the small genome were interrogated, and nearly half of those exhibited significant changes in accumulation. Punicalagin treatment altered the accumulation of proteins and enzymes needed for iron acquisition, and it altered amounts of enzymes for glycolysis, citric acid cycling, protein biosynthesis, and purine and pyrimidine biosynthesis. Punicalagin treatment also induced an SOS cellular response to damaged DNA. Transcriptional comparison of marker genes shows that the punicalagin-induced iron starvation and SOS responses resembles those produced by EDTA and ciprofloxacin. These results show that punicalagin adversely alters bacterial growth by disrupting iron homeostasis and that it induces SOS, possibly through DNA biosynthesis inhibition. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physical modeling of SOS P channel MOSFET and comparison with bulk devices

International Nuclear Information System (INIS)

Merckel, G.; Gris, Y.

1976-01-01

The main technological steps applied to P channel MOSFET's on SOS are recalled. A large-signal model derived from a physical analysis is presented. Gate-source and gate-drain capacitors have been linearized versus drain voltage. Due to low injection, the only diffusion capacitance of the source-substrate forward biased diode, and the depletion capacitance of the drain-substrate reverse biased diode were taken into account. Some typical parameters measured on SOS and bulk devices are given [fr

The Ustilago maydis effector Pep1 suppresses plant immunity by inhibition of host peroxidase activity.

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Christoph Hemetsberger

Full Text Available The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1 as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H₂O₂ strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction.

Low Ascorbic Acid in the vtc-1 Mutant of Arabidopsis Is Associated with Decreased Growth and Intracellular Redistribution of the Antioxidant System1

Science.gov (United States)

Veljovic-Jovanovic, Sonja D.; Pignocchi, Cristina; Noctor, Graham; Foyer, Christine H.

2001-01-01

Ascorbic acid has numerous and diverse roles in plant metabolism. We have used the vtc-1 mutant of Arabidopsis, which is deficient in ascorbate biosynthesis, to investigate the role of ascorbate concentration in growth, regulation of photosynthesis, and control of the partitioning of antioxidative enyzmes. The mutant possessed 70% less ascorbate in the leaves compared with the wild type. This lesion was associated with a slight increase in total glutathione but no change in the redox state of either ascorbate or glutathione. In vtc-1, total ascorbate in the apoplast was decreased to 23% of the wild-type value. The mutant displayed much slower shoot growth than the wild type when grown in air or at high CO2 (3 mL L−1), where oxidative stress is diminished. Leaves were smaller, and shoot fresh weight and dry weight were lower in the mutant. No significant differences in the light saturation curves for CO2 assimilation were found in air or at high CO2, suggesting that the effect on growth was not due to decreased photosynthetic capacity in the mutant. Analysis of chlorophyll a fluorescence quenching revealed only a slight effect on non-photochemical energy dissipation. Hydrogen peroxide contents were similar in the leaves of the vtc-1 mutant and the wild type. Total leaf peroxidase activity was increased in the mutant and compartment-specific differences in ascorbate peroxidase (APX) activity were observed. In agreement with the measurements of enzyme activity, the expression of cytosolic APX was increased, whereas that for chloroplast APX isoforms was either unchanged or slightly decreased. These data implicate ascorbate concentration in the regulation of the compartmentalization of the antioxidant system in Arabidopsis. PMID:11598218

Ectopic Expression of CsCTR1, a Cucumber CTR-Like Gene, Attenuates Constitutive Ethylene Signaling in an Arabidopsis ctr1-1 Mutant and Expression Pattern Analysis of CsCTR1 in Cucumber (Cucumis sativus

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Beibei Bie

2014-09-01

Full Text Available The gaseous plant hormone ethylene regulates many aspects of plant growth, development and responses to the environment. Constitutive triple response 1 (CTR1 is a central regulator involved in the ethylene signal transduction pathway. To obtain a better understanding of this particular pathway in cucumber, the cDNA-encoding CTR1 (designated CsCTR1 was isolated from cucumber. A sequence alignment and phylogenetic analyses revealed that CsCTR1 has a high degree of homology with other plant CTR1 proteins. The ectopic expression of CsCTR1 in the Arabidopsis ctr1-1 mutant attenuates constitutive ethylene signaling of this mutant, suggesting that CsCTR1 indeed performs its function as negative regulator of the ethylene signaling pathway. CsCTR1 is constitutively expressed in all of the examined cucumber organs, including roots, stems, leaves, shoot apices, mature male and female flowers, as well as young fruits. CsCTR1 expression gradually declined during male flower development and increased during female flower development. Additionally, our results indicate that CsCTR1 can be induced in the roots, leaves and shoot apices by external ethylene. In conclusion, this study provides a basis for further studies on the role of CTR1 in the biological processes of cucumber and on the molecular mechanism of the cucumber ethylene signaling pathway.

Sensorimotor learning in Dab1(scm) (scrambler) mutant mice.

Science.gov (United States)

Lalonde, R; Strazielle, C

2011-04-15

Homozygous Dab1(scm) mouse mutants with cell ectopias in cerebellar cortex and neocortex were compared with non-ataxic controls on two tests of motor coordination: rotorod and grid climbing. Even at the minimal speed of 4 rpm and unlike controls, none of the Dab1(scm) mutants reached criterion on the constant speed rotorod. In contrast, Dab1(scm) mutants improved their performances on the vertical grid over the course of the same number of trials. Thus, despite massive cerebellar degeneration, sensorimotor learning for equilibrium is still possible, indicating the potential usefulness of the grid-climbing test in determining residual functions in mice with massive cerebellar damage. Copyright © 2010. Published by Elsevier B.V.

Suppression of SOS-inducing activity of chemical mutagens by metabolites from microbial transformation of (-)-isolongifolene.

Science.gov (United States)

Sakata, Kazuki; Oda, Yoshimitsu; Miyazawa, Mitsuo

2010-02-24

In this study, biotransformation of (-)-isolongifolene (1) by Glomerella cingulata and suppressive effect on umuC gene expression by chemical mutagens 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) and aflatoxin B(1) (AFB(1)) of the SOS response in Salmonella typhimurium TA1535/pSK1002 were investigated. Initially, 1 was carried out the microbial transformation by G. cingulata. The result found that 1 was converted into (-)-isolongifolen-9-one (2), (-)-(2S)-13-hydroxy-isolongifolen-9-one (3), and (-)-(4R)-4-hydroxy-isolongifolen-9-one (4) by G. cingulata, and their conversion rates were 60, 25, and 15%, respectively. The metabolites suppressed the SOS-inducing activity of furylfuramid and AFB(1) in the umu test. Comound 2 showed gene expression by chemical mutagens furylfuramide and AFB(1) was suppressed 54 and 50% at <0.5 mM, respectively. Compound 2 is the most effective compound in this experiment.

Preliminary Study of the Characteristics of Several Glossy Cabbage (Brassica oleracea var. capitata L. Mutants

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Tang Jun

2015-09-01

Full Text Available To determine the characteristics and potential practical applications of glossy cabbage (Brassica oleracea var. capitata L. mutants, five different glossy mutants were studied. The amount of epicuticular wax covering the mutant leaves was only approximately 30% that of the wild-type (WT leaves. The wax crystals of WT plants were columnar and linear, while they were granular and rod-shaped in the mutants. Additionally, in WT cabbage, the primary wax components were alkanes, alcohols, fatty acids, ketones, and aldehydes. There was a significant decrease in the abundance of alkanes and ketones in the wax of the mutants. The glossy-green trait of the mutants may be the result of an inhibited alkane-forming pathway. Higher rates of chlorophyll leaching and water loss demonstrate that the mutant leaves were more permeable and sensitive to drought stress than the WT leaves. Growth curve results indicated that the growth rate of mutant-1 and mutant-3 was slower than that of the corresponding WT cabbage, resulting in shorter plants. However, the growth rate of mutant-2 was not influenced by the lack of coating wax. An investigation of the agronomic traits and heterosis of the glossy cabbage mutants indicated that all five mutants had glossy-green leaves, which was a favorable characteristic. The F1 plants derived from crosses involving mutant-2 exhibited obvious heterosis, suggesting the observed glossy-green trait is controlled by a dominant gene. Therefore, mutant-2 may be useful as a source of genetic material for future cabbage breeding experiments.

TOMATOMA Update: Phenotypic and Metabolite Information in the Micro-Tom Mutant Resource.

Science.gov (United States)

Shikata, Masahito; Hoshikawa, Ken; Ariizumi, Tohru; Fukuda, Naoya; Yamazaki, Yukiko; Ezura, Hiroshi

2016-01-01

TOMATOMA (http://tomatoma.nbrp.jp/) is a tomato mutant database providing visible phenotypic data of tomato mutant lines generated by ethylmethane sulfonate (EMS) treatment or γ-ray irradiation in the genetic background of Micro-Tom, a small and rapidly growing variety. To increase mutation efficiency further, mutagenized M3 seeds were subjected to a second round of EMS treatment; M3M1 populations were generated. These plants were self-pollinated, and 4,952 lines of M3M2 mutagenized seeds were generated. We checked for visible phenotypes in the M3M2 plants, and 618 mutant lines with 1,194 phenotypic categories were identified. In addition to the phenotypic information, we investigated Brix values and carotenoid contents in the fruits of individual mutants. Of 466 samples from 171 mutant lines, Brix values and carotenoid contents were between 3.2% and 11.6% and 6.9 and 37.3 µg g(-1) FW, respectively. This metabolite information concerning the mutant fruits would be useful in breeding programs as well as for the elucidation of metabolic regulation. Researchers are able to browse and search this phenotypic and metabolite information and order seeds of individual mutants via TOMATOMA. Our new Micro-Tom double-mutagenized populations and the metabolic information could provide a valuable genetic toolkit to accelerate tomato research and potential breeding programs. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Natural modifiers of seed longevity in the Arabidopsis mutants abscisic acid insensitive3-5 (abi3-5) and leafy cotyledon1-3 (lec1-3)

NARCIS (Netherlands)

Sugliani, M.R.L.; Rajjou, L.; Clerkx, E.J.M.; Koornneef, M.; Soppe, W.J.J.

2009-01-01

• Seed longevity is an important trait in many crops and is essential for the success of most land plant species. Current knowledge of its molecular regulation is limited. The Arabidopsis mutants abscisic acid insensitive3-5 (abi3-5) and leafy cotyledon1-3 (lec1-3) have impaired seed maturation and

Induction of sos response in Escherichia Coli cells by gamma rays

International Nuclear Information System (INIS)

Fuentes Lorenzo, J.L.; Padron Soler, E.; Martin Hernandez, G.; Perez Tamayo, N.; del Sol Abascal, E.R.; Almeida Varela, E.

1996-01-01

The kinetics of sos response induction in Escherichia Coli cells was studied by means of the gene fusion SfiA:LacZ. In these cells, the specific beta galactosidase activity and the cellular growth rate showed an exponential behaviour. The sensitivity of the GC 2181 starin to gamma irradiation is equal to Do -1= 0.00088/Gy. The beta galactosidase activity

Transient Transcriptional Regulation of the CYS-C1 Gene and Cyanide Accumulation upon Pathogen Infection in the Plant Immune Response1[C][W

Science.gov (United States)

García, Irene; Rosas, Tábata; Bejarano, Eduardo R.; Gotor, Cecilia; Romero, Luis C.

2013-01-01

Cyanide is produced concomitantly with ethylene biosynthesis. Arabidopsis (Arabidopsis thaliana) detoxifies cyanide primarily through the enzyme β-cyanoalanine synthase, mainly by the mitochondrial CYS-C1. CYS-C1 loss of function is not toxic for the plant and leads to an increased level of cyanide in cys-c1 mutants as well as a root hairless phenotype. The classification of genes differentially expressed in cys-c1 and wild-type plants reveals that the high endogenous cyanide content of the cys-c1 mutant is correlated with the biotic stress response. Cyanide accumulation and CYS-C1 gene expression are negatively correlated during compatible and incompatible plant-bacteria interactions. In addition, cys-c1 plants present an increased susceptibility to the necrotrophic fungus Botrytis cinerea and an increased tolerance to the biotrophic Pseudomonas syringae pv tomato DC3000 bacterium and Beet curly top virus. The cys-c1 mutation produces a reduction in respiration rate in leaves, an accumulation of reactive oxygen species, and an induction of the alternative oxidase AOX1a and pathogenesis-related PR1 expression. We hypothesize that cyanide, which is transiently accumulated during avirulent bacterial infection and constitutively accumulated in the cys-c1 mutant, uncouples the respiratory electron chain dependent on the cytochrome c oxidase, and this uncoupling induces the alternative oxidase activity and the accumulation of reactive oxygen species, which act by stimulating the salicylic acid-dependent signaling pathway of the plant immune system. PMID:23784464

Kinetic and dose dependencies of the SOS-induction in E.coli K-12 (uvrA) cells exposed to different UV doses

International Nuclear Information System (INIS)

Komova, O.V.; Kandiano, E.S.; Malavina, G.; )

2000-01-01

Kinetic and dose dependencies of the SOS-induction in E. coli (uvrA) cells exposed to UV light were investigated. below 2 J/m 2 the rate of the SOS-induction increased with dose. Maximal level of the SOS-response was proportional to the UV dose. Pyrimidine dimers were necessary for the induction. In the dose range 2-10 J/m 2 the rate of SOS-induction decreased with dose. Dose-maximum response curve was non-linear. Pyrimidine dimers were not required for the induction. nature of the molecular events leading to the SOS-induction at low and high doses was discussed [ru

Chemical trapping and characterization of small oxoacids of sulfur (SOS) generated in aqueous oxidations of H2S.

Science.gov (United States)

Kumar, Murugaeson R; Farmer, Patrick J

2018-04-01

Small oxoacids of sulfur (SOS) are elusive molecules like sulfenic acid, HSOH, and sulfinic acid, HS(O)OH, generated during the oxidation of hydrogen sulfide, H 2 S, in aqueous solution. Unlike their alkyl homologs, there is a little data on their generation and speciation during H 2 S oxidation. These SOS may exhibit both nucleophilic and electrophilic reactivity, which we attribute to interconversion between S(II) and S(IV) tautomers. We find that SOS may be trapped in situ by derivatization with nucleophilic and electrophilic trapping agents and then characterized by high resolution LC MS. In this report, we compare SOS formation from H 2 S oxidation by a variety of biologically relevant oxidants. These SOS appear relatively long lived in aqueous solution, and thus may be involved in the observed physiological effects of H 2 S. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Association between GRB2/Sos and insulin receptor substrate 1 is not sufficient for activation of extracellular signal-regulated kinases by interleukin-4: implications for Ras activation by insulin.

Science.gov (United States)

Pruett, W; Yuan, Y; Rose, E; Batzer, A G; Harada, N; Skolnik, E Y

1995-03-01

Insulin receptor substrate 1 (IRS-1) mediates the activation of a variety of signaling pathways by the insulin and insulin-like growth factor 1 receptors by serving as a docking protein for signaling molecules with SH2 domains. We and others have shown that in response to insulin stimulation IRS-1 binds GRB2/Sos and have proposed that this interaction is important in mediating Ras activation by the insulin receptor. Recently, it has been shown that the interleukin (IL)-4 receptor also phosphorylates IRS-1 and an IRS-1-related molecule, 4PS. Unlike insulin, however, IL-4 fails to activate Ras, extracellular signal-regulated kinases (ERKs), or mitogen-activated protein kinases. We have reconstituted the IL-4 receptor into an insulin-responsive L6 myoblast cell line and have shown that IRS-1 is tyrosine phosphorylated to similar degrees in response to insulin and IL-4 stimulation in this cell line. In agreement with previous findings, IL-4 failed to activate the ERKs in this cell line or to stimulate DNA synthesis, whereas the same responses were activated by insulin. Surprisingly, IL-4's failure to activate ERKs was not due to a failure to stimulate the association of tyrosine-phosphorylated IRS-1 with GRB2/Sos; the amounts of GRB2/Sos associated with IRS-1 were similar in insulin- and IL-4-stimulated cells. Moreover, the amounts of phosphatidylinositol 3-kinase activity associated with IRS-1 were similar in insulin- and IL-4-stimulated cells. In contrast to insulin, however, IL-4 failed to induce tyrosine phosphorylation of Shc or association of Shc with GRB2. Thus, ERK activation correlates with Shc tyrosine phosphorylation and formation of an Shc/GRB2 complex. Thus, ERK activation correlates with Shc tyrosine phosphorylation and formation of an Shc/GRB2 complex. Previous studies have indicated that activation of ERks in this cell line is dependent upon Ras since a dominant-negative Ras (Asn-17) blocks ERK activation by insulin. Our findings, taken in the context

SOS formats and meta-theory : 20 years after

NARCIS (Netherlands)

Mousavi, M.R.; Reniers, M.A.; Groote, J.F.

2007-01-01

In 1981 Structural Operational Semantics (SOS) was introduced as a systematic way to define operational semantics of programming languages by a set of rules of a certain shape [G.D. Plotkin, A structural approach to operational semantics, Technical Report DAIMI FN-19, Computer Science Department,

Development of Database Software with Plant Mutant Resources

International Nuclear Information System (INIS)

Namgoong, Won; Lee, M. J.; Kim, J. D.; Ma, N. K.

2007-03-01

In this research, mutants induced by nuclear radiation are developed information computerised system. The status and progress on the collection, identification and utilization of mutants in Korea are introduced. And it was produced home page, manual, test record, construction of system

Engineering of plants with improved properties as biofuels feedstocks by vessel-specific complementation of xylan biosynthesis mutants

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Petersen Pia Damm

2012-11-01

Full Text Available Abstract Background Cost-efficient generation of second-generation biofuels requires plant biomass that can easily be degraded into sugars and further fermented into fuels. However, lignocellulosic biomass is inherently recalcitrant toward deconstruction technologies due to the abundant lignin and cross-linked hemicelluloses. Furthermore, lignocellulosic biomass has a high content of pentoses, which are more difficult to ferment into fuels than hexoses. Engineered plants with decreased amounts of xylan in their secondary walls have the potential to render plant biomass a more desirable feedstock for biofuel production. Results Xylan is the major non-cellulosic polysaccharide in secondary cell walls, and the xylan deficient irregular xylem (irx mutants irx7, irx8 and irx9 exhibit severe dwarf growth phenotypes. The main reason for the growth phenotype appears to be xylem vessel collapse and the resulting impaired transport of water and nutrients. We developed a xylan-engineering approach to reintroduce xylan biosynthesis specifically into the xylem vessels in the Arabidopsis irx7, irx8 and irx9 mutant backgrounds by driving the expression of the respective glycosyltransferases with the vessel-specific promoters of the VND6 and VND7 transcription factor genes. The growth phenotype, stem breaking strength, and irx morphology was recovered to varying degrees. Some of the plants even exhibited increased stem strength compared to the wild type. We obtained Arabidopsis plants with up to 23% reduction in xylose levels and 18% reduction in lignin content compared to wild-type plants, while exhibiting wild-type growth patterns and morphology, as well as normal xylem vessels. These plants showed a 42% increase in saccharification yield after hot water pretreatment. The VND7 promoter yielded a more complete complementation of the irx phenotype than the VND6 promoter. Conclusions Spatial and temporal deposition of xylan in the secondary cell wall of

SOS-1 seminar about safety culture

International Nuclear Information System (INIS)

Wahlstroem, B.; Hammar, L.

2000-01-01

The aim of the seminar was to discuss safety culture in nuclear power utilities, and to exchange experiences about how the term safety culture is accepted by the personnel. The titles of the presentations are: 1) Organisational culture. General ideas as basis for organising; 2) Safety culture - ability and will; 3) View on safety culture at Swedish and Finnish nuclear power plants; 4) Safety culture at Barsebaeck Power Company; 5) Safety culture at Olkiluoto Nuclear Power Plant; 6) How do we improve the safety culture at OKG AB?; 7) Safety culture activities at Ringhals; 8) Aspects in relation to safety culture; 9) Development of regulatory activities/effectiveness of STUK - development as an aspect of culture; 10) Organisational culture research at STUK's Department of Nuclear Reactor Regulation; 11) The IAEA safety culture services; 12) Industrial safety - different perspectives and cultures. (EHS)

Pep1, a secreted effector protein of Ustilago maydis, is required for successful invasion of plant cells.

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Gunther Doehlemann

2009-02-01

Full Text Available The basidiomycete Ustilago maydis causes smut disease in maize. Colonization of the host plant is initiated by direct penetration of cuticle and cell wall of maize epidermis cells. The invading hyphae are surrounded by the plant plasma membrane and proliferate within the plant tissue. We identified a novel secreted protein, termed Pep1, that is essential for penetration. Disruption mutants of pep1 are not affected in saprophytic growth and develop normal infection structures. However, Deltapep1 mutants arrest during penetration of the epidermal cell and elicit a strong plant defense response. Using Affymetrix maize arrays, we identified 116 plant genes which are differentially regulated in Deltapep1 compared to wild type infections. Most of these genes are related to plant defense. By in vivo immunolocalization, live-cell imaging and plasmolysis approaches, we detected Pep1 in the apoplastic space as well as its accumulation at sites of cell-to-cell passages. Site-directed mutagenesis identified two of the four cysteine residues in Pep1 as essential for function, suggesting that the formation of disulfide bridges is crucial for proper protein folding. The barley covered smut fungus Ustilago hordei contains an ortholog of pep1 which is needed for penetration of barley and which is able to complement the U. maydis Deltapep1 mutant. Based on these results, we conclude that Pep1 has a conserved function essential for establishing compatibility that is not restricted to the U. maydis / maize interaction.

Construction and isolation of radiation sensitive mutants of Escherichia Coli; Construccion y aislamiento de mutantes de E. Coli sensibles a radiacion

Energy Technology Data Exchange (ETDEWEB)

Cuapio P, P

1996-12-31

Damage to DNA by ionizing radiation consists mainly of single (SSB) and double (DSB) strand breaks as well as several types of base alterations, all of which may be removed by different repair mechanisms. Radiation also induces the SOS response, a set of repair and/or damage tolerance genes involved in functions such as replication arrest, excision and recombination repair, increase of both spontaneous and induced mutation and prophage induction, among others. The degree of SOS induction is related to the type and amount of damage and may be easily determined by a simple colorimetric assay, the SOS chromo test. In order to investigate the role of protection and/or repair genes on bacterial radiosensitivity, E. coli strains defective in either oxyR, recJ or recO genes were constructed and their respective SOS response to radiation, duly examined. The results show that although lack of regulatory gene oxyR increases radiosensitivity, it is the deficiencies in recJ and recO which seem to be more important. Both genes appear to take part in the repair of DSB and according to SOS measurements, their role is related also to damage processing conducent to the SOS triggering signal. A hypothetical working mechanism for the purpose, partially supported by the data is proposed. (Author).

RpoS plays a central role in the SOS induction by sub-lethal aminoglycoside concentrations in Vibrio cholerae.

Science.gov (United States)

Baharoglu, Zeynep; Krin, Evelyne; Mazel, Didier

2013-01-01

Bacteria encounter sub-inhibitory concentrations of antibiotics in various niches, where these low doses play a key role for antibiotic resistance selection. However, the physiological effects of these sub-lethal concentrations and their observed connection to the cellular mechanisms generating genetic diversification are still poorly understood. It is known that, unlike for the model bacterium Escherichia coli, sub-minimal inhibitory concentrations (sub-MIC) of aminoglycosides (AGs) induce the SOS response in Vibrio cholerae. SOS is induced upon DNA damage, and since AGs do not directly target DNA, we addressed two issues in this study: how sub-MIC AGs induce SOS in V. cholerae and why they do not do so in E. coli. We found that when bacteria are grown with tobramycin at a concentration 100-fold below the MIC, intracellular reactive oxygen species strongly increase in V. cholerae but not in E. coli. Using flow cytometry and gfp fusions with the SOS regulated promoter of intIA, we followed AG-dependent SOS induction. Testing the different mutation repair pathways, we found that over-expression of the base excision repair (BER) pathway protein MutY relieved this SOS induction in V. cholerae, suggesting a role for oxidized guanine in AG-mediated indirect DNA damage. As a corollary, we established that a BER pathway deficient E. coli strain induces SOS in response to sub-MIC AGs. We finally demonstrate that the RpoS general stress regulator prevents oxidative stress-mediated DNA damage formation in E. coli. We further show that AG-mediated SOS induction is conserved among the distantly related Gram negative pathogens Klebsiella pneumoniae and Photorhabdus luminescens, suggesting that E. coli is more of an exception than a paradigm for the physiological response to antibiotics sub-MIC.

Integral formula for elliptic SOS models with domain walls and a reflecting end

Energy Technology Data Exchange (ETDEWEB)

Lamers, Jules, E-mail: j.lamers@uu.nl

2015-12-15

In this paper we extend previous work of Galleas and the author to elliptic SOS models. We demonstrate that the dynamical reflection algebra can be exploited to obtain a functional equation characterizing the partition function of an elliptic SOS model with domain-wall boundaries and one reflecting end. Special attention is paid to the structure of the functional equation. Through this approach we find a novel multiple-integral formula for that partition function.

Comparative Analysis of Light-Harvesting Antennae and State Transition in chlorina and cpSRP Mutants1[OPEN

Science.gov (United States)

Wang, Peng

2016-01-01

State transitions in photosynthesis provide for the dynamic allocation of a mobile fraction of light-harvesting complex II (LHCII) to photosystem II (PSII) in state I and to photosystem I (PSI) in state II. In the state I-to-state II transition, LHCII is phosphorylated by STN7 and associates with PSI to favor absorption cross-section of PSI. Here, we used Arabidopsis (Arabidopsis thaliana) mutants with defects in chlorophyll (Chl) b biosynthesis or in the chloroplast signal recognition particle (cpSRP) machinery to study the flexible formation of PS-LHC supercomplexes. Intriguingly, we found that impaired Chl b biosynthesis in chlorina1-2 (ch1-2) led to preferentially stabilized LHCI rather than LHCII, while the contents of both LHCI and LHCII were equally depressed in the cpSRP43-deficient mutant (chaos). In view of recent findings on the modified state transitions in LHCI-deficient mutants (Benson et al., 2015), the ch1-2 and chaos mutants were used to assess the influence of varying LHCI/LHCII antenna size on state transitions. Under state II conditions, LHCII-PSI supercomplexes were not formed in both ch1-2 and chaos plants. LHCII phosphorylation was drastically reduced in ch1-2, and the inactivation of STN7 correlates with the lack of state transitions. In contrast, phosphorylated LHCII in chaos was observed to be exclusively associated with PSII complexes, indicating a lack of mobile LHCII in chaos. Thus, the comparative analysis of ch1-2 and chaos mutants provides new evidence for the flexible organization of LHCs and enhances our understanding of the reversible allocation of LHCII to the two photosystems. PMID:27663408

Dwarf mutant of Papaver somniferum with high morphine content

International Nuclear Information System (INIS)

Chauhan, S.P.; Patra, N.K.; Srivastava, H.K.

1987-01-01

Opium poppy, Papaver somniferum L. is an important medicinal plant known for its morphine, codeine, and thebaine alkaloids. This Institute had earlier released two latex opium yielding poppy varieties, Shyama and Shweta, which are now cultivated by the farmers under the supervision of the Narcotic Department of the Government of India. However, both these varieties became susceptible to downy mildew (Peronospora arborescens). Lodging due to heavy capsule weight is another problem affecting latex yield. With these problems in mind, we undertook mutation breeding on the above mentioned two varieties employing gamma rays (5 kR, 15 kR, 20 kR) and EMS (0.2%, 0.4%, 0.6%) and combined mutagens (5 kR + 0.2% EMS, 5 kR + 0.4% EMS and 5 kR + 0.6% EMS). M 1 from the treated seeds (405 plants) was raised in winter 1984-85. M 2 generation of 13,500 plants (i.e. 270 M 1 progenies x 50 plants) was raised in winter 1985/86. A dwarf mutant with high morphine content was identified in M 2 from the variety Shweta treated with 5 kR + 0.4% EMS. The mutant differs by its dwarf stature, compact leaf arrangements, multilocular capsules, increased capsule number, and small capsule size. The mutant is under testing for its superior morphine production. It may be used as dwarf gene source in hybridization for improving lodging resistance. This mutant is a novel type, which was not available in our germplasm collection

Atomic orbital-based SOS-MP2 with tensor hypercontraction. I. GPU-based tensor construction and exploiting sparsity

Energy Technology Data Exchange (ETDEWEB)

Song, Chenchen; Martínez, Todd J. [Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

2016-05-07

We present a tensor hypercontracted (THC) scaled opposite spin second order Møller-Plesset perturbation theory (SOS-MP2) method. By using THC, we reduce the formal scaling of SOS-MP2 with respect to molecular size from quartic to cubic. We achieve further efficiency by exploiting sparsity in the atomic orbitals and using graphical processing units (GPUs) to accelerate integral construction and matrix multiplication. The practical scaling of GPU-accelerated atomic orbital-based THC-SOS-MP2 calculations is found to be N{sup 2.6} for reference data sets of water clusters and alanine polypeptides containing up to 1600 basis functions. The errors in correlation energy with respect to density-fitting-SOS-MP2 are less than 0.5 kcal/mol for all systems tested (up to 162 atoms).

Atomic orbital-based SOS-MP2 with tensor hypercontraction. I. GPU-based tensor construction and exploiting sparsity.

Science.gov (United States)

Song, Chenchen; Martínez, Todd J

2016-05-07

We present a tensor hypercontracted (THC) scaled opposite spin second order Møller-Plesset perturbation theory (SOS-MP2) method. By using THC, we reduce the formal scaling of SOS-MP2 with respect to molecular size from quartic to cubic. We achieve further efficiency by exploiting sparsity in the atomic orbitals and using graphical processing units (GPUs) to accelerate integral construction and matrix multiplication. The practical scaling of GPU-accelerated atomic orbital-based THC-SOS-MP2 calculations is found to be N(2.6) for reference data sets of water clusters and alanine polypeptides containing up to 1600 basis functions. The errors in correlation energy with respect to density-fitting-SOS-MP2 are less than 0.5 kcal/mol for all systems tested (up to 162 atoms).

istSOS, a new sensor observation management system: software architecture and a real-case application for flood protection

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M. Cannata

2015-11-01

Full Text Available istSOS (Istituto scienze della Terra Sensor Observation Service is an implementation of the Sensor Observation Service (SOS standard from the Open Geospatial Consortium. The development of istSOS started in 2009 in order to provide a simple implementation of the SOS for the management, provision and integration of hydro-meteorological data collected in Canton Ticino (Southern Switzerland. istSOS is an Open Source, entirely written in Python and based on reliable software like PostgreSQL/PostGIS and Apache/mod_wsgi. This paper illustrates the latest software enhancements, including a RESTful Web service and a Web-based graphical user interface, which enable a better and simplified interaction with measurements and SOS service settings. The robustness of the implemented solution has been validated in a real-case application: the Verbano Lake Early Warning System. In this application, near real-time data have to be exchanged by inter-regional partners and used in a hydrological model for lake level forecasting and flooding hazard assessment. This system is linked with a dedicated geoportal used by the civil protection for the management, alert and protection of the population and the assets of the Locarno area. Practical considerations, technical issues and foreseen improvements are presented and discussed.

Preferência de Bemisia tabaci biótipo B em linhagens mutantes de algodoeiro Bemisia tabaci biotype B preference in mutant cotton lines

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Francisco das Chagas Vidal Neto

2008-02-01

Full Text Available Os efeitos de caracteres mutantes morfológicos do algodoeiro (Gossypium hirsutum L. r. latifolium Hutch.: folha okra, bráctea frego e planta vermelha, em relação à resistência à mosca-branca (Bemisia tabaci biótipo B Hemiptera: Aleyrodidae, foram avaliados em experimentos com ou sem chance de escolha. Os experimentos foram conduzidos em casa-de-vegetação, no delineamento de blocos ao acaso, em fatorial 23 + 1, com quatro repetições. O mutante com a característica planta vermelha foi menos atrativo e menos preferido para oviposição, em relação à planta verde, em ambos os ensaios, com ou sem escolha. Não houve preferência quanto à forma da folha e ao tipo de bráctea.The effects of cotton lines (Gossypium hirsutum L. r. latifolium Hutch. with mutants morphologic characteristics: okra leaf, frego bract and red plant in relation to host plant resistance to whitefly (Bemisia tabaci bioyipe B Hemiptera: Aleyrodidae, were evaluated in choice or no choice assays. The assays were carried out in the greenhouse conditions, according to a completely randomized block design, in a 23 + 1 in a factorial arrangement with four replications. The mutant with red plant characteristic was less attractive and less preferred for oviposition than the normal green plant does, in both, whit or without choice tests. It did not have preference in relation to the form of the leaf and bract type.

Commercialization Of Orchid Mutants For Floriculture Industry

International Nuclear Information System (INIS)

Sakinah Ariffin; Zaiton Ahmad

2014-01-01

Orchids are the main contributors to cut flower industry in Malaysia with an existing good market and a huge business potential. Orchid industry has been established in Malaysia since 1960s but only started to develop and expand since 1980s. Continuous development of new orchid varieties is essential to meet customers' demands. Orchid mutagenesis research using gamma irradiation at Malaysian Nuclear Agency has successfully generated a number of new orchid varieties with commercial potentials. Therefore, Nuclear Malaysia has collaborated with an industrial partner, Hexagon Green Sdn Bhd (HGSB), to carry out commercialization research on these mutants under a Technofund project entitled 'Pre-Commercialization of Mutant Orchids for Cut Flowers Industry' from July 2011 to July 2014. Through this collaboration, Dendrobium orchid mutant plants developed by Nuclear Malaysia were transferred to HGSB's commercial orchid nursery at Bukit Changgang Agrotechnology Park, Banting, Selangor, for mass-propagation. The activities include evaluations on plant growth performance, flower quality, post harvest and market potential of these mutants. Mutants with good field performance have been identified and filed for Plant Variety Protection (PVP) with Department of Agriculture Malaysia. This paper describes outputs from this collaboration and activities undertaken in commercializing these mutants. (author)

Responses of Soybean Mutant Lines to Aluminium under In Vitro and In Vivo Condition

International Nuclear Information System (INIS)

Yuliasti; Sudarsono

2011-01-01

The main limited factors of soybean plants expansion in acid soil are Aluminium (Al) toxicity and low pH. The best approach to solve this problem is by using Al tolerance variety. In vitro or in vivo selections using selective media containing AlCl 3 and induced callus embryonic of mutant lines are reliable methods to develop a new variety. The objectives of this research are to evaluate response of soybean genotypes against AlCl 3 under in vitro and in vivo condition. Addition of 15 part per million (ppm) AlCl 3 into in vitro and in vivo media severely affected plant growth. G3 soybean mutant line was identified as more tolerant than the control soybean cultivar Tanggamus. This mutant line was able to survive under more severe AlCl 3 concentrations (15 ppm) under in vitro conditions. Under in vivo conditions, G1 and G4 mutants were also identified as more tolerant than Tanggamus since they produced more pods and higher dry seed weigh per plant. Moreover, G4 mutant line also produced more dry seed weight per plant than Tanggamus when they were grown on soil containing high Al concentration 8.1 me/100 gr = 81 ppm Al +3 . (author)

The yeast complex I equivalent NADH dehydrogenase rescues pink1 mutants.

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Sven Vilain

2012-01-01

Full Text Available Pink1 is a mitochondrial kinase involved in Parkinson's disease, and loss of Pink1 function affects mitochondrial morphology via a pathway involving Parkin and components of the mitochondrial remodeling machinery. Pink1 loss also affects the enzymatic activity of isolated Complex I of the electron transport chain (ETC; however, the primary defect in pink1 mutants is unclear. We tested the hypothesis that ETC deficiency is upstream of other pink1-associated phenotypes. We expressed Saccaromyces cerevisiae Ndi1p, an enzyme that bypasses ETC Complex I, or sea squirt Ciona intestinalis AOX, an enzyme that bypasses ETC Complex III and IV, in pink1 mutant Drosophila and find that expression of Ndi1p, but not of AOX, rescues pink1-associated defects. Likewise, loss of function of subunits that encode for Complex I-associated proteins displays many of the pink1-associated phenotypes, and these defects are rescued by Ndi1p expression. Conversely, expression of Ndi1p fails to rescue any of the parkin mutant phenotypes. Additionally, unlike pink1 mutants, fly parkin mutants do not show reduced enzymatic activity of Complex I, indicating that Ndi1p acts downstream or parallel to Pink1, but upstream or independent of Parkin. Furthermore, while increasing mitochondrial fission or decreasing mitochondrial fusion rescues mitochondrial morphological defects in pink1 mutants, these manipulations fail to significantly rescue the reduced enzymatic activity of Complex I, indicating that functional defects observed at the level of Complex I enzymatic activity in pink1 mutant mitochondria do not arise from morphological defects. Our data indicate a central role for Complex I dysfunction in pink1-associated defects, and our genetic analyses with heterologous ETC enzymes suggest that Ndi1p-dependent NADH dehydrogenase activity largely acts downstream of, or in parallel to, Pink1 but upstream of Parkin and mitochondrial remodeling.

Gamma-radiation Mutagenesis in Genetically Unstable Barley Mutants. Pt. 1. Chlorophyll Mutations in Allelic tw Mutants and Their Revertants

International Nuclear Information System (INIS)

Vaitkuniene, V.

1995-01-01

Genotypical environment is an essential factor determining the mutability of mutants of the same type. Decreased chlorophyll mutant frequency was a common characteristic of all tested tw type (tw, tw 1 , tw 2 ) mutants induced in barley c. 'Auksiniai II'. The mutability of all the tested revertants was close to that of the initial c. 'Auksiniai II'. (author). 9 refs., 2 tabs

ALS mutant SOD1 interacts with G3BP1 and affects stress granule dynamics.

Science.gov (United States)

Gal, Jozsef; Kuang, Lisha; Barnett, Kelly R; Zhu, Brian Z; Shissler, Susannah C; Korotkov, Konstantin V; Hayward, Lawrence J; Kasarskis, Edward J; Zhu, Haining

2016-10-01

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease. Mutations in Cu/Zn superoxide dismutase (SOD1) are responsible for approximately 20 % of the familial ALS cases. ALS-causing SOD1 mutants display a gain-of-toxicity phenotype, but the nature of this toxicity is still not fully understood. The Ras GTPase-activating protein-binding protein G3BP1 plays a critical role in stress granule dynamics. Alterations in the dynamics of stress granules have been reported in several other forms of ALS unrelated to SOD1. To our surprise, the mutant G93A SOD1 transgenic mice exhibited pathological cytoplasmic inclusions that co-localized with G3BP1-positive granules in spinal cord motor neurons. The co-localization was also observed in fibroblast cells derived from familial ALS patient carrying SOD1 mutation L144F. Mutant SOD1, unlike wild-type SOD1, interacted with G3BP1 in an RNA-independent manner. Moreover, the interaction is specific for G3BP1 since mutant SOD1 showed little interaction with four other RNA-binding proteins implicated in ALS. The RNA-binding RRM domain of G3BP1 and two particular phenylalanine residues (F380 and F382) are critical for this interaction. Mutant SOD1 delayed the formation of G3BP1- and TIA1-positive stress granules in response to hyperosmolar shock and arsenite treatment in N2A cells. In summary, the aberrant mutant SOD1-G3BP1 interaction affects stress granule dynamics, suggesting a potential link between pathogenic SOD1 mutations and RNA metabolism alterations in ALS.

Characterization of the Pseudomonas aeruginosa recA analog and its protein product: rec-102 is a mutant allele of the P. aeruginosa PAO recA gene

Energy Technology Data Exchange (ETDEWEB)

Kokjohn, T.A.; Miller, R.V.

1987-04-01

We cloned a 2.3-kilobase-pair fragment of the Pseudomonas aeruginosa PAO chromosome which is capable of complementing recA mutations of Escherichia coli. The recA-complementing activity was further localized to a 1.5-kilobase-pair PvuII-HindIII fragment. Southern blot analysis under conditions of high stringency indicated that DNA sequence homology is shared by the E. coli recA gene and the P. aeruginosa recA analog. The cloned recA analog was shown to restore resistance to methyl methanesulfonate, nitrofurantoin, and UV irradiation to E. coli recA mutants. Upon introduction of the cloned P. aeruginosa gene, these mutants regained recombination proficiency in HfrH-mediated conjugation and the ability to induce lambda prophages and SOS functions (din gene transcription) after exposure to DNA-damaging agents. Lambda prophage carrying a cI ind mutation was not inducible, suggesting that the mechanism of induction of these SOS functions by the P. aeruginosa RecA analog is similar to that by the activated E. coli RecA protein. The product of the recA analog was identified in minicells as a protein of approximately 47,000 daltons. Western blot analysis using anti-E. coli RecA antibody demonstrated that this protein is antigenically cross-reactive with the E. coli recA protein. The recA-containing fragment was cloned into the broad-host-range vector pCP13 and introduced into Rec- strains of P. aeruginosa containing the rec-102 allele. The plasmid was shown to restore recombination proficiency in FP5-mediated conjugations and to restore resistance to UV irradiation and methyl methanesulfonate to these Rec- mutants. It was shown that a wild-type allele of rec-102 is necessary for UV-mediated induction of D3 and F116 prophages. The cloned recA analog restored the UV inducibility of these prophages in rec-102 mutants.

Characterization of the Pseudomonas aeruginosa recA analog and its protein product: rec-102 is a mutant allele of the P. aeruginosa PAO recA gene

International Nuclear Information System (INIS)

Kokjohn, T.A.; Miller, R.V.

1987-01-01

We cloned a 2.3-kilobase-pair fragment of the Pseudomonas aeruginosa PAO chromosome which is capable of complementing recA mutations of Escherichia coli. The recA-complementing activity was further localized to a 1.5-kilobase-pair PvuII-HindIII fragment. Southern blot analysis under conditions of high stringency indicated that DNA sequence homology is shared by the E. coli recA gene and the P. aeruginosa recA analog. The cloned recA analog was shown to restore resistance to methyl methanesulfonate, nitrofurantoin, and UV irradiation to E. coli recA mutants. Upon introduction of the cloned P. aeruginosa gene, these mutants regained recombination proficiency in HfrH-mediated conjugation and the ability to induce lambda prophages and SOS functions (din gene transcription) after exposure to DNA-damaging agents. Lambda prophage carrying a cI ind mutation was not inducible, suggesting that the mechanism of induction of these SOS functions by the P. aeruginosa RecA analog is similar to that by the activated E. coli RecA protein. The product of the recA analog was identified in minicells as a protein of approximately 47,000 daltons. Western blot analysis using anti-E. coli RecA antibody demonstrated that this protein is antigenically cross-reactive with the E. coli recA protein. The recA-containing fragment was cloned into the broad-host-range vector pCP13 and introduced into Rec- strains of P. aeruginosa containing the rec-102 allele. The plasmid was shown to restore recombination proficiency in FP5-mediated conjugations and to restore resistance to UV irradiation and methyl methanesulfonate to these Rec- mutants. It was shown that a wild-type allele of rec-102 is necessary for UV-mediated induction of D3 and F116 prophages. The cloned recA analog restored the UV inducibility of these prophages in rec-102 mutants

Clear Plaque Mutants of Lactococcal Phage TP901-1

DEFF Research Database (Denmark)

Kot, Witold; Kilstrup, Mogens; Vogensen, Finn K.

2016-01-01

We report a method for obtaining turbid plaques of the lactococcal bacteriophage TP901-1 and its derivative TP901-BC1034. We have further used the method to isolate clear plaque mutants of this phage. Analysis of 8 such mutants that were unable to lysogenize the host included whole genome...

Mapping of a Cellulose-Deficient Mutant Named dwarf1-1 in Sorghum bicolor to the Green Revolution Gene gibberellin20-oxidase Reveals a Positive Regulatory Association between Gibberellin and Cellulose Biosynthesis.

Science.gov (United States)

Petti, Carloalberto; Hirano, Ko; Stork, Jozsef; DeBolt, Seth

2015-09-01

Here, we show a mechanism for expansion regulation through mutations in the green revolution gene gibberellin20 (GA20)-oxidase and show that GAs control biosynthesis of the plants main structural polymer cellulose. Within a 12,000 mutagenized Sorghum bicolor plant population, we identified a single cellulose-deficient and male gametophyte-dysfunctional mutant named dwarf1-1 (dwf1-1). Through the Sorghum propinquum male/dwf1-1 female F2 population, we mapped dwf1-1 to a frameshift in GA20-oxidase. Assessment of GAs in dwf1-1 revealed ablation of GA. GA ablation was antagonistic to the expression of three specific cellulose synthase genes resulting in cellulose deficiency and growth dwarfism, which were complemented by exogenous bioactive gibberellic acid application. Using quantitative polymerase chain reaction, we found that GA was positively regulating the expression of a subset of specific cellulose synthase genes. To cross reference data from our mapped Sorghum sp. allele with another monocotyledonous plant, a series of rice (Oryza sativa) mutants involved in GA biosynthesis and signaling were isolated, and these too displayed cellulose deficit. Taken together, data support a model whereby suppressed expansion in green revolution GA genes involves regulation of cellulose biosynthesis. © 2015 American Society of Plant Biologists. All Rights Reserved.

Characterization of a null allelic mutant of the rice NAL1 gene reveals its role in regulating cell division.

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Dan Jiang

Full Text Available Leaf morphology is closely associated with cell division. In rice, mutations in Narrow leaf 1 (NAL1 show narrow leaf phenotypes. Previous studies have shown that NAL1 plays a role in regulating vein patterning and increasing grain yield in indica cultivars, but its role in leaf growth and development remains unknown. In this report, we characterized two allelic mutants of NARROW LEAF1 (NAL1, nal1-2 and nal1-3, both of which showed a 50% reduction in leaf width and length, as well as a dwarf culm. Longitudinal and transverse histological analyses of leaves and internodes revealed that cell division was suppressed in the anticlinal orientation but enhanced in the periclinal orientation in the mutants, while cell size remained unaltered. In addition to defects in cell proliferation, the mutants showed abnormal midrib in leaves. Map-based cloning revealed that nal1-2 is a null allelic mutant of NAL1 since both the whole promoter and a 404-bp fragment in the first exon of NAL1 were deleted, and that a 6-bp fragment was deleted in the mutant nal1-3. We demonstrated that NAL1 functions in the regulation of cell division as early as during leaf primordia initiation. The altered transcript level of G1- and S-phase-specific genes suggested that NAL1 affects cell cycle regulation. Heterogeneous expression of NAL1 in fission yeast (Schizosaccharomyces pombe further supported that NAL1 affects cell division. These results suggest that NAL1 controls leaf width and plant height through its effects on cell division.

Phenotypic characterization and inheritance of two foliar mutants in pea (Pisum Sativum L.): 'Reduced leaf size' and 'Orange leaf'

International Nuclear Information System (INIS)

Naidenova, N.; Vassilevska-Ivanova, R.; Tcekova, Z.

2003-01-01

Two foliar pea (Pisum sativum L.) mutants characterized by reduced leaf size (2/978) and orange leaf (2/1409 M) were established. Both mutants were described morphologically and their productivity potential , pollen viability and inheritance of the mutant traits were evaluated. The mutant 2/978 was identified after irradiation of dry seeds from cv Borek with 15 Gy fast neutrons and was related to the leaf mutation 'rogue'. Reciprocal crosses between mutant 2/978 and cv Borel were executed, and F 1 and F 2 generations were analyzed. The altered leaf trait was presented in all F 1 plants suggesting a dominant character. F 2 segregation data indicated that the trait was controlled by a single dominant gene. The mutant 2/1409M originated from the mutant 2/978 after irradiation with 50 Gy γ-rays. The main mutant's phenotypic characteristic was the orange-yellow coloration of leaves and plants. After of series of crosses it was established that induced chlorophyll mutation is monogenic, recessive and both mutant traits are independently inherited. Two mutants could be used as appropriate plant material for genetic and biological investigations

Mechanism of SOS-induced targeted and untargeted mutagenesis in E. coli

International Nuclear Information System (INIS)

Maenhaut-Michel, G.

1985-01-01

This paper retraces the evolution of hypotheses concerning mechanisms of SOS induced mutagenesis. Moreover, it reports some recent data which support a new model for the mechanism of targeted and untargeted mutagenesis in E. coli. In summary, the SOS mutator effect, which is responsible for untargeted mutagenesis and perhaps for the misincorporation step in targeted mutagenesis, is believed to involve a fidelity function associated with DNA polymerase III and does not require the umuC gene product. umuC and umuD gene products are probably required specifically for elongation of DNA synthesis past blocking lesions, i.e. to allow mutagenic replication of damaged DNA

Induction of the SOS response in ultraviolet-irradiated Escherichia coli analyzed by dynamics of LexA, RecA and SulA proteins

International Nuclear Information System (INIS)

Aksenov, S.V.

1999-01-01

The SOS response in Escherichia coli is induced after DNA-damaging treatments including ultraviolet light. Regulation of the SOS response is accomplished through specific interaction of the two SOS regulator proteins, LexA and RecA. In ultraviolet light treated cells nucleotide excision repair is the major system that removes the induced lesions from the DNA. Here, induction of the SOS response in Escherichia coli with normal and impaired excision repair function is studied by simulation of intracellular levels of regulatory LexA and RecA proteins, and SulA protein. SulA protein is responsible for SOS-inducible cell division inhibition. Results of the simulations show that nucleotide excision repair influences time-courses of LexA , RecA and SulA induction by modulating the dynamics of RecA protein distribution between its normal and SOS-activated forms

Kinetic and dose dependences of the SOS-induction in E.coli K-12 (uvrA) cells exposed to the different UV doses

International Nuclear Information System (INIS)

Komova, O.V.; Kandiano, E.S.; Malavya, G.

1999-01-01

The kinetic and dose dependences of the SOS-induction in E.coli (uvrA) cells exposed to UV light were investigated. Below 2 J/m 2 the rate of the SOS-induction increased with dose. The maximal level of the SOS-response was proportional to the UV dose. Pyrimidine dimers were necessary for the induction. In the dose range 2-10 J/m 2 the rate of the SOS-induction decreased with dose. The dose-response curve was non-linear. Pyrimidine dimers were not required for the induction. The nature of the molecular events leading to the SOS-induction at low and high UV doses was discussed. (author)