Constitutive nuclear factor-kappa B mRNA, protein overexpression and enhanced DNA-binding activity in thymidylate synthase inhibitor-resistant tumour cells

In this study, the gene copy number, mRNA and protein expression levels and nuclear DNA-binding activity of nuclear factor kappa B (NF-kappaB) were compared in a panel of five pairs of thymidylate synthase (TS) inhibitor-resistant and wild-type parent cancer cell lines. High constitutive NF-kappaB DNA-binding activity was detected in all chemoresistant cell lines. The upregulated NF-kappaB activity was composed of NF-kappaB subunits p50 and p65. Four out of five resistant cell lines constitutively overexpressed NF-kappaB p50 and p63 mRNA and protein. One resistant cell line with the highest NF-kappaB DNA-binding activity showed normal p50 and p65 protein expression. No NF-kappaB gene amplification was detected in resistant cell lines. Transient exposure of wild-type RKOWT and H630(WT) cells to 5-FU induced NF-kappaB DNA-binding activity but had no effect on NF-kappaB protein expression in these cells, Our results indicate that high constitutive NF-kappaB activity caused by its gene overexpression is an intrinsic character of TS inhibitor-resistant cells. NF-kappaB can antagonise anticancer drug-induced apoptosis. High NF-kappaB expression and nuclear activity in TS inhibitor-resistant cancer cells may play an important role in the chemoresistance

RNAi-mediated suppression of isoprene emission in poplar transiently impacts phenolic metabolism under high temperature and high light intensities: a transcriptomic and metabolomic analysis

In plants, isoprene plays a dual role: (a) as thermo-protective agent proposed to prevent degradation of enzymes/membrane structures involved in photosynthesis, and (b) as reactive molecule reducing abiotic oxidative stress. The present work addresses the question whether suppression of isoprene emission interferes with genome wide transcription rates and metabolite fluxes in grey poplar (Populusxcanescens) throughout the growing season. Gene expression and metabolite profiles of isoprene emitting wild type plants and RNAi-mediated non-isoprene emitting poplars were compared by using poplar Affymetrix microarrays and non-targeted FT-ICR-MS (Fourier transform ion cyclotron resonance mass spectrometry). We observed a transcriptional down-regulation of genes encoding enzymes of phenylpropanoid regulatory and biosynthetic pathways, as well as distinct metabolic down-regulation of condensed tannins and anthocyanins, in non-isoprene emitting genotypes during July, when high temperature and light intensities possibly caused transient drought stress, as indicated by stomatal closure. Under these conditions leaves of non-isoprene emitting plants accumulated hydrogen peroxide (H2O2), a signaling molecule in stress response and negative regulator of anthocyanin biosynthesis. The absence of isoprene emission under high temperature and light stress resulted transiently in a new chemo(pheno)type with suppressed production of phenolic compounds. This may compromise inducible defenses and may render non-isoprene emitting poplars more susceptible to environmental stress

Identification of Key Processes that Control Tumor Necrosis Factor Availability in a Tuberculosis Granuloma

Tuberculosis (TB) granulomas are organized collections of immune cells comprised of macrophages, lymphocytes and other cells that form in the lung as a result of immune response to Mycobacterium tuberculosis (Mtb) infection. Formation and maintenance of granulomas are essential for control of Mtb infection and are regulated in part by a pro-inflammatory cytokine, tumor necrosis factor-α (TNF). To characterize mechanisms that control TNF availability within a TB granuloma, we developed a multi-scale two compartment partial differential equation model that describes a granuloma as a collection of immune cells forming concentric layers and includes TNF/TNF receptor binding and trafficking processes. We used the results of sensitivity analysis as a tool to identify experiments to measure critical model parameters in an artificial experimental model of a TB granuloma induced in the lungs of mice following injection of mycobacterial antigen-coated beads. Using our model, we then demonstrated that the organization of immune cells within a TB granuloma as well as TNF/TNF receptor binding and intracellular trafficking are two important factors that control TNF availability and may spatially coordinate TNF-induced immunological functions within a granuloma. Further, we showed that the neutralization power of TNF-neutralizing drugs depends on their TNF binding characteristics, including TNF binding kinetics, ability to bind to membrane-bound TNF and TNF binding stoichiometry. To further elucidate the role of TNF in the process of granuloma development, our modeling and experimental findings on TNF-associated molecular scale aspects of the granuloma can be incorporated into larger scale models describing the immune response to TB infection. Ultimately, these modeling and experimental results can help identify new strategies for TB disease control/therapy

Search for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during the LIGO–Virgo run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate

Molecular cloning and characterisation of the ribC gene from Bacillus subtilis:A point mutation in ribC results in riboflavin overproduction

A mutation leading to roseoflavin resistance and deregulated riboflavin biosynthesis was mapped in the genome of the riboflavin-overproducing Bacillus subtilis strains RB52 and RB50 at map position 147 degrees. The chromosomal location indicates that the deregulating mutation in RB52 and RB50 is an allele of the previously identified ribC mutation. We cloned the ribC gene and found that it encodes a putative 36-kDa protein. Surprisingly, RibC has significant sequence similarity to flavin kinases and FAD synthases from various other bacterial species. By comparing the deduced amino acid sequence of RibC from the wild-type parent strain of RB50 with the RibC sequence from the riboflavin-overexpressing RB50 mutant we identified a point mutation that resulted in a Gly to Ser exchange in the C-terminal region of the product