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SOS response

Andreas U Müller, Frank Imkamp, Eilika Weber-Ban
Mycobacteria exhibit two DNA damage response pathways: the LexA/RecA-dependent SOS response and a LexA/RecA-independent pathway. Using a combination of transcriptomics and genome-wide binding site analysis, we demonstrate that PafBC (proteasome accessory factor B and C), encoded in the Pup-proteasome system (PPS) gene locus, is the transcriptional regulator of the predominant LexA/RecA-independent pathway. Comparison of the resulting PafBC regulon with the DNA damage response of Mycobacterium smegmatis reveals that the majority of induced DNA repair genes are upregulated by PafBC...
June 19, 2018: Cell Reports
Wendy W K Mok, Mark P Brynildsen
Bacterial persisters are subpopulations of phenotypic variants in isogenic cultures that can survive lethal doses of antibiotics. Their tolerances are often attributed to reduced activities of antibiotic targets, which limit corruption and damage in persisters compared with bacteria that die from treatment. However, that model does not hold for nongrowing populations treated with ofloxacin, a fluoroquinolone, where antibiotic-induced damage is comparable between cells that live and those that die. To understand how those persisters achieve this feat, we employed a genetic system that uses orthogonal control of MazF and MazE, a toxin and its cognate antitoxin, to generate model persisters that are uniformly tolerant to ofloxacin...
June 18, 2018: Proceedings of the National Academy of Sciences of the United States of America
Brittany A Niccum, Heewook Lee, Wazim MohammedIsmail, Haixu Tang, Patricia L Foster
When the DNA polymerase that replicates the Escherichia coli chromosome, DNA Pol III, makes an error, there are two primary defenses against mutation: proofreading by the epsilon subunit of the holoenzyme and mismatch repair. In proofreading deficient strains, mismatch repair is partially saturated and the cell's response to DNA damage, the SOS response, may be partially induced. To investigate the nature of replication errors, we used mutation accumulation experiments and whole genome sequencing to determine mutation rates and mutational spectra across the entire chromosome of strains deficient in proofreading, mismatch repair, and the SOS response...
June 15, 2018: Genetics
Yongqing Yang, Yan Guo
Salt stress is a major environmental factor limiting plant growth and productivity. A better understanding of the mechanisms mediating salt resistance will help researchers design ways to improve crop performance under adverse environmental conditions. Salt stress can lead to ionic stress, osmotic stress, and secondary stresses, particularly oxidative stress, in plants. Therefore, to adapt to salt stress, plants rely on signals and pathways that re-establish cellular ionic, osmotic, and reactive oxygen species (ROS) homeostasis...
June 15, 2018: Journal of Integrative Plant Biology
Heejeong Lee, Dong Gun Lee
Arenicin-1, a 21-mer antimicrobial peptide exerts significant broad-spectrum antimicrobial activity with membrane-active mechanisms. However, owing to multiple mechanisms of cell death, the antibacterial mechanism of arenicin-1 requires detailed analysis. In the present study, arenicin-1-treated bacteria underwent an apoptosis-like response, which was mechanistically and morphologically similar to eukaryotic apoptosis. Changes in the physiological status of arenicin-1-treated bacterial cells involved accumulation of reactive oxygen species, imbalance of intracellular calcium gradients, disruption of membrane potential, bacterial caspase-like protein activation, and DNA damage...
June 7, 2018: Current Genetics
Gopal Selvakumar, Charlotte C Shagol, Kiyoon Kim, Seunggab Han, Tongmin Sa
BACKGROUND: The interaction between arbuscular mycorrhizal fungi (AMF) and AMF spore associated bacteria (SAB) were previously found to improve mycorrhizal symbiotic efficiency under saline stress, however, the information about the molecular basis of this interaction remain unknown. Therefore, the present study aimed to investigate the response of maize plants to co-inoculation of AMF and SAB under salinity stress. RESULTS: The co-inoculation of AMF and SAB significantly improved plant dry weight, nutrient content of shoot and root tissues under 25 or 50 mM NaCl...
June 5, 2018: BMC Plant Biology
Christine Blume, Renata Del Giudice, Malgorzata Wislowska, Dominik P J Heib, Manuel Schabus
While it is a well-established finding that subject's own names (SON) or familiar voices are salient during wakefulness, we here investigated processing of environmental stimuli during sleep including deep N3 and REM sleep. Besides the effects of sleep depth we investigated how sleep-specific EEG patterns (i.e. sleep spindles and slow oscillations [SOs]) relate to stimulus processing. Using 256-channel EEG we studied processing of auditory stimuli by means of event-related oscillatory responses (de-/synchronisation, ERD/ERS) and potentials (ERPs) in N = 17 healthy sleepers...
May 30, 2018: NeuroImage
Pilar Liceras-Boillos, David Jimeno, Rósula García-Navas, L Francisco Lorenzo-Martín, Mauricio Menacho-Marquez, Carmen Segrelles, Carmela Gómez, Nuria Calzada, Rocío Fuentes-Mateos, Jesús M Paramio, Xosé R Bustelo, Fernando C Baltanás, Eugenio Santos
Using Sos1-KO, Sos2-KO and Sos1/2-DKO mice, we assessed the functional role of Sos1 and Sos2 in skin homeostasis under physiological and/or pathological conditions. Sos1 depletion resulted in significant alterations of skin homeostasis including reduced keratinocyte proliferation, altered hair follicle and blood vessel integrity in dermis, and reduced adipose tissue in hypodermis. These defects worsened significantly when both Sos1 and Sos2 were absent. Simultaneous Sos1/2 disruption led to severe impairment of the ability to repair skin wounds as well as to almost complete ablation of the neutrophil-mediated inflammatory response in the injury site...
May 29, 2018: Molecular and Cellular Biology
Delphine Arbelet-Bonnin, Ibtissem Ben Hamed-Laouti, Patrick Laurenti, Chedly Abdelly, Karim Ben Hamed, François Bouteau
We recently identified two behaviours in cultured cells of the salt accumulating halophyte Cakile maritima: one related to a sustained depolarization due to Na+ influx through the non-selective cation channels leading to programmed cell death of these cells, a second one related to a transient depolarization allowing cells to survive (Ben Hamed-Laouti, 2016). In this study, we considered at the cellular level mechanisms that could participate to the exclusion of Na+ out of the cell and thus participate in the regulation of the internal contents of Na+ and cell survival...
July 2018: Plant Science: An International Journal of Experimental Plant Biology
Evelyne Krin, Sebastian Aguilar Pierlé, Odile Sismeiro, Bernd Jagla, Marie-Agnès Dillies, Hugo Varet, Oihane Irazoki, Susana Campoy, Zoé Rouy, Stéphane Cruveiller, Claudine Médigue, Jean-Yves Coppée, Didier Mazel
BACKGROUND: 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. RESULTS: Comprehensive transcriptional profiling allowed us to define the full landscape of promoters and transcripts active in V...
May 21, 2018: BMC Genomics
Zhong-Ke Jiang, Li Tuo, Da-Lin Huang, Ilya A Osterman, Anton P Tyurin, Shao-Wei Liu, Dmitry A Lukyanov, Petr V Sergiev, Olga A Dontsova, Vladimir A Korshun, Fei-Na Li, Cheng-Hang Sun
Endophytic actinobacteria are one of the important pharmaceutical resources and well known for producing different types of bioactive substances. Nevertheless, detection of the novelty, diversity, and bioactivity on endophytic actinobacteria isolated from mangrove plants are scarce. In this study, five different mangrove plants, Avicennia marina, Aegiceras corniculatum, Kandelia obovota, Bruguiera gymnorrhiza , and Thespesia populnea , were collected from Beilun Estuary National Nature Reserve in Guangxi Zhuang Autonomous Region, China...
2018: Frontiers in Microbiology
Tracy Adole, Jadunandan Dash, Peter M Atkinson
Information on the response of vegetation to different environmental drivers, including rainfall, forms a critical input to ecosystem models. Currently, such models are run based on parameters that, in some cases, are either assumed or lack supporting evidence (e.g., that vegetation growth across Africa is rainfall-driven). A limited number of studies have reported that the onset of rain across Africa does not fully explain the onset of vegetation growth, for example, drawing on the observation of pre-rain flush effects in some parts of Africa...
May 16, 2018: Global Change Biology
Ornella Mailén Ontañon, Claudia Landi, Alfonso Carleo, Assunta Gagliardi, Laura Bianchi, Paola Solange González, Elizabeth Agostini, Luca Bini
Acinetobacter guillouiae SFC 500-1A is an environmental bacterium able to efficiently co-remediate phenol and Cr(VI). To further understand the molecular mechanisms triggered in this strain during the bioremediation process, variations in the proteomic profile after treatment with phenol and phenol plus Cr(VI) were evaluated. The proteomic analysis revealed the induction of the β-ketoadipate pathway for phenol oxidation and the assimilation of degradation products through TCA cycle and glyoxylate shunt. Phenol exposure increased the abundance of proteins associated to energetic processes and ATP synthesis, but it also triggered cellular stress...
April 27, 2018: Journal of Hazardous Materials
Gaylen A Uhlich, Elisa Andreozzi, Bryan J Cottrell, Erin R Reichenberger, Xinmin Zhang, George C Paoli
The high frequency of prophage insertions in the mlrA gene of clinical serotype O157:H7 isolates renders such strains deficient in csgD-dependent biofilm formation but prophage induction may restore certain mlrA properties. In this study we used transcriptomics to study the effect of high and low sulfamethoxazole-trimethoprim (SMX-TM) concentrations on prophage induction, biofilm regulation, and virulence gene expression in strain PA20 under environmental conditions following 5-hour and 12-hour exposures in broth or on agar...
2018: PloS One
Sarah S Henrikus, Antoine M van Oijen, Andrew Robinson
In many bacterial species, DNA damage triggers the SOS response; a pathway that regulates the production of DNA repair and damage tolerance proteins, including error-prone DNA polymerases. These specialised polymerases are capable of bypassing lesions in the template DNA, a process known as translesion synthesis (TLS). Specificity for lesion types varies considerably between the different types of TLS polymerases. TLS polymerases are mainly described as working in the context of replisomes that are stalled at lesions or in lesion-containing gaps left behind the replisome...
April 26, 2018: Current Genetics
Alexandra Götz, Matthias Lechner, Andreas Mader, Benedikt von Bronk, Erwin Frey, Madeleine Opitz
The bacterial SOS response is a cellular reaction to DNA damage, that, among other actions, triggers the expression of colicin - toxic bacteriocins in Escherichia coli that are released to kill close relatives competing for resources. However, it is largely unknown, how the complex network regulating toxin expression controls the time-point of toxin release to prevent premature release of inefficient protein concentrations. Here, we study how different regulatory mechanisms affect production and release of the bacteriocin ColicinE2 in Escherichia coli...
April 25, 2018: Scientific Reports
V A Chistyakov, E V Prazdnova, M S Mazanko, M N Churilov, V K Chmyhalo
The use of platinum-based anticancer drugs is limited by both their side effects and their effect on normal microflora's metagenome. Drugs that possess mutagenic and genotoxic properties may cause mutations in microbial genomes that contribute to the emergence of resistance to antimicrobial preparations and the development of complications after chemotherapy. The effects of cisplatin and oxaliplatin on microorganisms were studied using bacterial biosensors - E. coli strains MG1655 pKatG-lux, which reacts to the generation of hydrogen peroxide; MG1655 pSoxS-lux, which reacts to the superoxide anion radical; and the MG1655 pColD-lux strain, which detects DNA damage...
March 2018: Molekuliarnaia Biologiia
Lu Zuo, Huan Jiong Wang, Rong Gao Liu, Yang Liu, Rong Shang
Vegetation phenology is a comprehensive indictor for the responses of terrestrial ecosystem to climatic and environmental changes. Remote sensing spectrum has been widely used in the extraction of vegetation phenology information. However, there are many differences between phenology extracted by remote sensing and site observations, with their physical meaning remaining unclear. We selected one tile of MODIS data in northeastern China (2000-2014) to examine the SOS and EOS differences derived from the normalized difference vegetation index (NDVI) and the simple ratio vegetation index (SR) based on both the red and near-infrared bands...
February 2018: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
Simon van Vliet, Alma Dal Co, Annina R Winkler, Stefanie Spriewald, Bärbel Stecher, Martin Ackermann
Gene expression levels in clonal bacterial groups have been found to be spatially correlated. These correlations can partly be explained by the shared lineage history of nearby cells, although they could also arise from local cell-cell interactions. Here, we present a quantitative framework that allows us to disentangle the contributions of lineage history, long-range spatial gradients, and local cell-cell interactions to spatial correlations in gene expression. We study pathways involved in toxin production, SOS stress response, and metabolism in Escherichia coli microcolonies and find for all pathways that shared lineage history is the main cause of spatial correlations in gene expression levels...
April 25, 2018: Cell Systems
Pradeep Bandaru, Yasushi Kondo, John Kuriyan
The guanine-nucleotide exchange factor (GEF) Son-of-Sevenless (SOS) plays a critical role in metazoan signaling by converting Ras•GDP (guanosine diphosphate) to Ras•GTP (guanosine triphosphate) in response to tyrosine kinase activation. Structural studies have shown that SOS differs from other Ras-specific GEFs in that SOS is itself activated by Ras•GTP binding to an allosteric site, distal to the site of nucleotide exchange. The activation of SOS involves membrane recruitment and conformational changes, triggered by lipid binding, that open the allosteric binding site for Ras•GTP...
April 2, 2018: Cold Spring Harbor Perspectives in Medicine
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