Extreme photometric and polarimetric variability of blazar S4 0954+65 at its maximum optical and γ-ray brightness levels

In 2022 the BL Lac object S4 0954+65 underwent a major variability phase, reaching its historical maximum brightness in the optical and γ -ray bands. We present optical photometric and polarimetric data acquired by the Whole Earth Blazar Telescope (WEBT) Collaboration from 2022 April 6 to July 6. Many episodes of unprecedented fast variability were detected, implying an upper limit to the size of the emitting region as low as 10−4 parsec. The WEBT data show rapid variability in both the degree and angle of polarization. We analyse different models to explain the polarization behaviour in the framework of a twisting jet model, which assumes that the long-term trend of the flux is produced by variations in the emitting region viewing angle. All the models can reproduce the average trend of the polarization degree, and can account for its general anticorrelation with the flux, but the dispersion of the data requires the presence of intrinsic mechanisms, such as turbulence, shocks, or magnetic reconnection. The WEBT optical data are compared to γ -ray data from the Fermi satellite. These are analysed with both fixed and adaptive binning procedures. We show that the strong correlation between optical and γ -ray data without measurable delay assumes different slopes in faint and high brightness states, and this is compatible with a scenario where in faint states we mainly see the imprint of the geometrical effects, while in bright states the synchrotron self-Compton process dominates

The Colorectal cancer disease-specific transcriptome may facilitate the discovery of more biologically and clinically relevant information

<p>Abstract</p> <p>Background</p> <p>To date, there are no clinically reliable predictive markers of response to the current treatment regimens for advanced colorectal cancer. The aim of the current study was to compare and assess the power of transcriptional profiling using a generic microarray and a disease-specific transcriptome-based microarray. We also examined the biological and clinical relevance of the disease-specific transcriptome.</p> <p>Methods</p> <p>DNA microarray profiling was carried out on isogenic sensitive and 5-FU-resistant HCT116 colorectal cancer cell lines using the Affymetrix HG-U133 Plus2.0 array and the Almac Diagnostics Colorectal cancer disease specific Research tool. In addition, DNA microarray profiling was also carried out on pre-treatment metastatic colorectal cancer biopsies using the colorectal cancer disease specific Research tool. The two microarray platforms were compared based on detection of probesets and biological information.</p> <p>Results</p> <p>The results demonstrated that the disease-specific transcriptome-based microarray was able to out-perform the generic genomic-based microarray on a number of levels including detection of transcripts and pathway analysis. In addition, the disease-specific microarray contains a high percentage of antisense transcripts and further analysis demonstrated that a number of these exist in sense:antisense pairs. Comparison between cell line models and metastatic CRC patient biopsies further demonstrated that a number of the identified sense:antisense pairs were also detected in CRC patient biopsies, suggesting potential clinical relevance.</p> <p>Conclusions</p> <p>Analysis from our <it>in vitro </it>and clinical experiments has demonstrated that many transcripts exist in sense:antisense pairs including <it>IGF2BP2</it>, which may have a direct regulatory function in the context of colorectal cancer. While the functional relevance of the antisense transcripts has been established by many studies, their functional role is currently unclear; however, the numbers that have been detected by the disease-specific microarray would suggest that they may be important regulatory transcripts. This study has demonstrated the power of a disease-specific transcriptome-based approach and highlighted the potential novel biologically and clinically relevant information that is gained when using such a methodology.</p

Cross-tolerance to abiotic stresses in halophytes: Application for phytoremediation of organic pollutants

International audienceHalopytes are plants able to tolerate high salt concentrations but no clear definition was retained for them. In literature, there are more studies that showed salt-enhanced tolerance to other abiotic stresses compared to investigations that found enhanced salt tolerance by other abiotic stresses in halophytes. The phenomenon by which a plant resistance to a stress induces resistance to another is referred to as cross-tolerance. In this work, we reviewed cross-tolerance in halophytes at the physiological, biochemical, and molecular levels. A special attention was accorded to the cross-tolerance between salinity and organic pollutants that could allow halophytes a higher potential of xenobiotic phytoremediation in comparison with glycophytes

Response of rice to salinity risk- from a physiological outlook to laboratory focussed experimental approach

Salinity is one of the major environmental constraint that restricts crop growth and yield. Rice (Oryza sativa L.), one of the major staple crops, consumed by more than half of the world's population is regarded to be salt sensitive. Salt stress in plants occurs in two phases over time, i.e. osmotic and ionic phase. The application of salt stress also plays an important role in deciding whether the crop is responding to salt stress or salt shock. Further, the response to salinity stress is specific to the crop developmental stage. Hence an experimental approach that takes into account these factors (1) delineating the two phases (2) salt stress vs salt shock and (3) developmental stage is crucial in exploring salt determinants in rice. The review presented here examines the data in these aspects and further, provides various approaches in light of the current understanding. The focus is on the different approaches available to researchers including Petri plate based method, hydroponics and soil based approaches for screening and understanding the plant response to salinity. The review will be helpful for researchers to choose an appropriate experimental procedure for studying tolerance to NaCl stress using rice as a model system in the laboratory

Cloning and Characterization of a Gene Encoding Ubiquitin Conjugating Enzyme from the Mangrove Species, <i>Avicennia marina </i>(Forsk.) Vierh.

164-169Covalent attachment of ubiquitin has been implicated in mediating proteolysis of the cellular proteins by Ubiquitin- proteasome pathway. Ubiquitin activating enzyme (E1), ubiquitin conjugating enzyme (E2), and ubiquitin protein ligase (E3) are the three enzymes involved in this process. This paper reports the isolation of a gene that codes for the ubiquitin conjugating enzyme in Avicennia marina (AmUBC2), and regulation of its expression at RNA level under salt stress. Deduced amino acid sequence of AmUBC2 showed 96% identity with UBC2 of Arabidopsis thaliana and also 73-78% identity with RAD6 DNA repair protein of Homo sapiens, Rattus norvegicus, Caenorhabditis elegans, Drosophila melanogaster, Arabidopsis thaliana and Saccharomyces cerevisiae. Multiple alignment analysis showed that the amino acid residues in the core region of UBC2 were highly conserved across different taxa in the evolutionary hierarchy. While some ubiquitin conjugating enzymes were induced under salt, heat and heavy metal stress in different tissues in plants, Northern analysis in the present study has clearly shown that the expression of UBC2 is not induced by salt stress either in root or in leaf tissues in A. marina. Southern hybridization of genomic DNA with gene-specific probe showed that AmUBC2 is a single copy gene