Lightweight Encrytion Scheme against Flow Analysis in Multi-Hop Wireless Network Based on Network Coding

Traffic analysis is a major issue faced in multi-hop wireless networks (MWN) in the case of privacy preservation. Network coding is essential in achieving greater capacity for any network and we extend this network coding for privacy preservation in multi-hop networks as it offers coding and mixing functions at intermediate nodes. Certain existing privacy preserving methods like onion routing can be employed here. Applying homomorphic encryption on Global Encoding Vectors(GEV’s), our method offers confidentiality and privacy preserving features. Only the sink has capability of decrypting the message content by inverting the GEV. Here, we focus on the privacy issue in order to prevent traffic analysis and flow tracing and achieve source anonymity in MWNs. Source anonymity refers to carrying the communication through the network maintaining the secrecy of the source node. Energy consumption when compared with the existing system was found to be reduced. Simulative evaluation by NS2 shows the efficiency of the system. Keywords: MWN, Privacy preservation, NS2, GEV

Safety of Treatment Regimens Containing Bedaquiline and Delamanid in the endTB Cohort.

BACKGROUND: Safety of treatment for multidrug-resistant tuberculosis (MDR/RR-TB) can be an obstacle to treatment completion. Evaluate safety of longer MDR/RR-TB regimens containing bedaquiline and/or delamanid. METHODS: Multicentre (16 countries), prospective, observational study reporting incidence and frequency of clinically relevant adverse events of special interest (AESIs) among patients who received MDR/RR-TB treatment containing bedaquiline and/or delamanid. The AESIs were defined a priori as important events caused by bedaquiline, delamanid, linezolid, injectables, and other commonly used drugs. Occurrence of these events was also reported by exposure to the likely causative agent. RESULTS: Among 2296 patients, the most common clinically relevant AESIs were peripheral neuropathy (26.4%), electrolyte depletion (26.0%), and hearing loss (13.2%) with an incidence per 1000 person months of treatment, 1000 person-months of treatment 21.5 (95% confidence interval [CI]: 19.8-23.2), 20.7 (95% CI: 19.1-22.4), and 9.7 (95% CI: 8.6-10.8), respectively. QT interval was prolonged in 2.7% or 1.8 (95% CI: 1.4-2.3)/1000 person-months of treatment. Patients receiving injectables (N = 925) and linezolid (N = 1826) were most likely to experience events during exposure. Hearing loss, acute renal failure, or electrolyte depletion occurred in 36.8% or 72.8 (95% CI: 66.0-80.0) times/1000 person-months of injectable drug exposure. Peripheral neuropathy, optic neuritis, and/or myelosuppression occurred in 27.8% or 22.8 (95% CI: 20.9-24.8) times/1000 patient-months of linezolid exposure. CONCLUSIONS: AEs often related to linezolid and injectable drugs were more common than those frequently attributed to bedaquiline and delamanid. MDR-TB treatment monitoring and drug durations should reflect expected safety profiles of drug combinations. CLINICAL TRIALS REGISTRATION: NCT02754765

Structural and Functional Characterization of the Soluble Cell Adhesion Molecule DdCAD-1in Dictyostelium discoideum

The cadA gene in Dictyostelium encodes a unique Ca2+-dependent cell adhesion molecule DdCAD-1. It is synthesized as a soluble protein in the cytoplasm and then transported to the plasma membrane by contractile vacuoles. The solution structures of Ca2+-free and Ca2+-bound DdCAD-1 reveals that it contains two β-sandwich domains, belonging to the βγ-crystallin and immunoglobulin fold classes, respectively. Whereas the N-terminal domain has a major role in homophilic binding, the C-terminal domain tethers the protein to the cell membrane. Although hydrophobic interactions constitute the major force for adhesion, electrostatic interactions may act as a ‘switch’ to regulate the homophilic binding by a change in electrostatic potential caused by the binding of Ca2+ to the three binding sites. To further investigate DdCAD-1 transport, DdCAD-1-GFP fusion proteins were expressed in cadA-null cells. Time-lapse microscopy revealed that DdCAD-1 was imported by invagination of the contractile vacuole membrane. The N-terminal, C-terminal domains, and two of the three Ca2+-binding site mutant forms of DdCAD-1 failed to enter the contractile vacuole, suggesting that Ca2+-binding and the integrity of DdCAD-1 are required for import. Indeed, proteins with altered conformation failed to enter the contractile vacuole, indicating that the import signal is integrated in the three-dimensional structure of DdCAD-1. Finally, we describe how the cadA gene acts as a single-gene green beard. In chimera experiments, cells expressing DdCAD-1 were more likely to form fruiting bodies than cadA-null cells on soil plates. Here cadA behaved as a single gene green beard. However, cadA exhibited anti-green beard behaviour on non-nutrient agar plates. Wild-type cells differentiated mostly into prestalk cells and eventually died, whereas the cadA-null cells survived as spores. DdCAD-1 was enriched in cell-cell contact regions of anterior cells, while it was mostly localized in the cytoplasm of posterior cells. The presence of DdCAD-1 on the cell surface of prestalk cells is crucial for cell sorting, which in turn explain the anti-green beard effect observed in chimeras containing cadA+ and cadA- cells. These observations demonstrate that DdCAD-1 plays a direct role in cell sorting through differential cell-cell adhesion which results from the differential distribution of DdCAD-1.Ph

Ras/ERK-signalling promotes tRNA synthesis and growth via the RNA polymerase III repressor Maf1 in <i>Drosophila</i>

<div><p>The small G-protein Ras is a conserved regulator of cell and tissue growth. These effects of Ras are mediated largely through activation of a canonical RAF-MEK-ERK kinase cascade. An important challenge is to identify how this Ras/ERK pathway alters cellular metabolism to drive growth. Here we report on stimulation of RNA polymerase III (Pol III)-mediated tRNA synthesis as a growth effector of Ras/ERK signalling in <i>Drosophila</i>. We find that activation of Ras/ERK signalling promotes tRNA synthesis both in vivo and in cultured <i>Drosophila</i> S2 cells. We also show that Pol III function is required for Ras/ERK signalling to drive proliferation in both epithelial and stem cells in <i>Drosophila</i> tissues. We find that the transcription factor Myc is required but not sufficient for Ras-mediated stimulation of tRNA synthesis. Instead we show that Ras signalling promotes Pol III function and tRNA synthesis by phosphorylating, and inhibiting the nuclear localization and function of the Pol III repressor Maf1. We propose that inhibition of Maf1 and stimulation of tRNA synthesis is one way by which Ras signalling enhances protein synthesis to promote cell and tissue growth.</p></div

Brf1 is required for intestinal stem cells (ISCs) homeostasis and for Ras-induced cell proliferation.

<p>(A, B) <i>UAS-Brf1 RNAi</i> was expressed adult ISCs and EBs using the <i>esg-GAL4</i>^<i>ts</i> system. Control flies were <i>esg-GAL4</i>^<i>ts</i> flies crossed to <i>w</i>^<i>1118</i>. Flies were then fed with sucrose or sucrose plus DSS (A) or Bleomycin (B) for 2 days. Intestines were then dissected and stained for phospho-histone H3 positive cells. Data represent the mean number of phospho-histone H3 cells per intestine +/ SEM. N >15 intestines per condition. (C) A UAS-Ras^V12 transgene was expressed in adult intestines using the <i>esg-GAL4</i>^<i>ts</i> driver. Control samples (WT) expressed <i>UAS-GFP</i> alone. Total RNA was isolated and levels of pre-tRNAs measured by qRT-PCR. N = 4 independent samples per condition. Data are presented as mean +/- SEM. (D) <i>UAS-Raf</i>^<i>gof</i> and <i>UAS-Brf1 RNAi</i> were expressed, either alone or together, in the adult ISCs and EBs using the <i>esg-Gal4</i>^<i>ts</i> system. <i>esg</i> positive cells are marked with GFP and DNA is stained with Hoechst dye. Knockdown of Brf 1(<i>UAS-Brf RNAi</i>) suppresses the increased proliferation seen with <i>UAS-Raf</i>^<i>gof</i> expression.</p

Ras signalling regulates dMaf1 phosphorylation.

<p>(A) <i>Drosophila</i> S2 cells were treated with 10 μM U0126 for 2 hours. Cells were then lysed and processed for SDS-PAGE and western blotting using the phos-tag reagent, as described in the Methods. The blots were then probed with an anti-dMaf1 antibody (top panel), an anti-total ERK antibody (middle panel) or an anti-phospho ERK antibody (lower panel) (B) Ras^V12 expression was induced in <i>Drosophila</i> S2 cells for 24 hours. Cells were then lysed and processed for SDS-PAGE and western blotting using the phos-tag reagent, as described in the Methods. The blots were then probed with an anti-dMaf1 antibody (top panel), an anti-total ERK antibody (middle panel) or an anti-phospho ERK antibody (lower panel). (C) A model for how Ras signalling may regulate Pol III and tRNA synthesis.</p

The Ras/ERK signalling pathway stimulates tRNA synthesis.

<p>(A, B) <i>Drosophila</i> S2 cells were treated with 10 μM U0126 for 2 hours. Total RNA was isolated and levels of either pre-tRNAs (A), or total tRNAs (B) measured by qRT-PCR. N = 15 independent samples per condition. (C, D) Raf was knocked down in <i>Drosophila</i> S2 cells by incubating cells with dsRNAs against <i>Raf</i>. Control cells were treated with dsRNA to GFP. Total RNA was isolated and levels of either pre-tRNAs (C), or total tRNAs (D) measured by qRT-PCR. N = 4 independent samples per condition. (E, F) Ras^V12 expression was induced in <i>Drosophila</i> S2 cells for 24 hours. Total RNA was isolated and levels of either pre-tRNAs (E), or total tRNAs (F) measured by qRT-PCR. N = 9 independent samples per condition. (G) <i>UAS-Raf</i>^<i>gof</i> was expressed in imaginal tissues using the <i>esg-GAL4</i>^<i>ts</i> system. Control flies were <i>esg-GAL4</i>^<i>ts</i> flies crossed to <i>w</i>^<i>1118</i>. Transgenes were induced by shifting larvae to 29°C at 48hrs of larval development, and then discs were dissected from wandering L3 stage larvae. Total RNA was isolated and levels of pre-tRNAs measured by qRT-PCR. N = 4 independent samples per condition. Data are presented as mean +/- SEM.</p

dMyc is required but not sufficient for Ras-induced tRNA synthesis.

<p>(A) Ras^V12 expression was induced in <i>Drosophila</i> S2 cells for 24 hours in either control cells or dMyc knockdown cells. dMyc was knocked down by incubating cells with dsRNA against <i>dMyc</i>. Control cells were treated with dsRNA to GFP. Total RNA was isolated with Trizol and analyzed by northern blotting using DIG-labelled antisense probes to tRNA^iMet or tRNA^Arg. Ethidium bromide stained 5S rRNA band was used as a loading control. (B, C and D) dMyc expression was induced in S2 cells for 24hrs, and then cells were treated with 10 μM U0126 or DMSO for 2 hours. Total RNA was isolated with Trizol and analyzed by qRT-PCR to measure levels of (B) pre-tRNAs, (C) <i>dMyc</i> mRNA, or (D) mRNA levels of three dMyc target genes—<i>NOP60B</i>, <i>PPAN</i> and <i>NOP5</i>. N = 4 independent samples per condition. Data are presented as mean +/-SEM.</p

Brf1 is required for Ras-induced tRNA synthesis and growth in both wing imaginal discs and adult midgut progenitor cells (AMPs).

<p>(A). Ras^V12 expression was induced in <i>Drosophila</i> S2 cells for 24 hours in either control cells or Brf1 knockdown cells, Brf1 was knocked down by incubating cells with dsRNA against Brf1. Control cells were treated with dsRNA to GFP. Total RNA was isolated with Trizol and analyzed by northern blotting using DIG-labelled antisense probes to tRNA^iMet or tRNA^Arg. Ethidium bromide stained 5S rRNA band was used as a loading control. (B, C) <i>UAS-EGFR</i> and <i>UAS-Brf1 RNAi</i> were expressed, either alone or together, in the dorsal compartment of larval wing imaginal discs using an <i>ap-Gal4</i> driver. Control discs were from <i>ap-Gal4</i> crossed to <i>w</i>^<i>1118</i>. Wing discs were dissected at the wandering L3 larval stage and the area of the GFP-marked dorsal compartment quantified using NIH imaging software (n > 50 wings per genotype, data presented as mean +/- SEM). Representative images are shown in (B), quantification of tissue area is shown in (C). (D) <i>UAS-EGFR</i> and <i>UAS-Brf1 RNAi</i> were expressed, either alone or together, in the <i>Drosophila</i> larval AMPs using the <i>esg-Gal4</i>^<i>ts</i> system. Larvae were shifted to 29°C at 24 hrs of development to induce transgene expression and dissected as L3 larvae. AMPs are marked <i>by UAS-GFP</i> expression. DNA is stained with Hoechst dye (blue). (E) The number of cells in each AMP cluster was quantified for each of the genotypes in D (left), and an additional similar experiment in which the Ras pathway was activated by expression of a <i>UAS-Raf</i>^<i>gof</i> transgene (right). Data are presented as box plots (25%, median and 75% values) with error bars indicating the min and max values.</p