CDK targeting of NBS1 promotes DNA-end resection, replication restart and homologous recombination

The conserved MRE11–RAD50–NBS1 (MRN) complex is an important sensor of DNA double-strand breaks (DSBs) and facilitates DNA repair by homologous recombination (HR) and end joining. Here, we identify NBS1 as a target of cyclin-dependent kinase (CDK) phosphorylation. We show that NBS1 serine 432 phosphorylation occurs in the S, G2 and M phases of the cell cycle and requires CDK activity. This modification stimulates MRN-dependent conversion of DSBs into structures that are substrates for repair by HR. Impairment of NBS1 phosphorylation not only negatively affects DSB repair by HR, but also prevents resumption of DNA replication after replication-fork stalling. Thus, CDK-mediated NBS1 phosphorylation defines a molecular switch that controls the choice of repair mode for DSBs.     

High-level gene expression in Aedes albopictus cells using a baculovirus Hr3 enhancer and IE1 transactivator

Background  

Aedes aegypti is the key vector of both the Yellow Fever and Dengue Fever viruses throughout many parts of the world. Low and variable transgene expression levels due to position effect and position effect variegation are problematic to efforts to create transgenic laboratory strains refractory to these viruses. Transformation efficiencies are also less than optimal, likely due to failure to detect expression from all integrated transgenes and potentially due to limited expression of the transposase required for transgene integration.     

Bleaching as a pathogenic response in scleractinian corals, evidenced by high concentrations of apoptotic and necrotic zooxanthellae

The study of symbiont cells lost from bleached scleractinian corals Acropora hyacinthus, Favites complanata, and Porites solida and octocorals Sarcophyton ehrenbergi, Sinularia sp., and Xenia sp. using flow cytometry shows that Symbiodinium die from either apoptosis or necrosis. Despite the majority of lost Symbiodinium cells being viable at 28 °C, the predominance of apoptotic and necrotic symbiont cells at higher temperatures indicates that the proportion of live cells decreases with increasing temperature. This implies that reinfection of corals at high temperatures by Symbiodinium lost from scleractinian corals may be less frequent than previously described, since many of the symbiont cells exhibit nonreversible symptoms of approaching cell death. The fraction of viable Symbiodinium cells lost from S. ehrenbergi, Xenia sp., and Sinularia at 32 °C was greater than that at 28 °C. At 34 °C, the fraction of viable cells lost from S. ehrenbergi and Xenia sp. fell but not from Sinularia sp., which suggests that their symbionts have higher temperature tolerances. Thus, Symbiodinium from octocorals may represent “pools” of genetically resistant symbionts available for reinfection of other reef organisms. This has been proposed previously for Symbiodinium in some scleractinian corals, but this is the first evidence for such, particularly for an octocoral. Many of the viable cells, determined using Trypan blue staining techniques, are in fact actually undergoing apoptosis or necrosis, when examined using Annexin V-fluor and propidium iodide staining profiles. The characterization of more apoptotic and necrotic cells than viable cells is critical, as this indicates that the loss of Symbiodinium cells cannot be beneficial to other bleached corals for symbiotic reassociation.     

Validating Livanow: Molecular Data Agree That Leeches, Branchiobdellidans, and Acanthobdella peledina Form a Monophyletic Group of Oligochaetes

To investigate the phylogenetic relationships of leeches, branchiobdellidans, and acanthobdellidans, whole nuclear 18S rDNA and over 650 bp of mitochondrial cytochrome c oxidase subunit I were acquired from 101 annelids, including 36 leeches, 18 branchiobdellidans, Acanthobdella peledina, as well as 28 oligochaetes and combined with homologous data for 17 polychaete outgroup taxa. Parsimony analysis of the combined aligned dataset supported monophyly of leeches, branchiobdellidans, and acanthobdellidans in 100% of jackknife replicates. Monophyly of the oligochaete order Lumbriculida with Acanthobdellida, Branchiobdellida, and Hirudinea was supported in 84% of jackknife replicates. These results provide support for the hypotheses that leeches and branchiobdellidans are sister groups, that acanthobdellidans are sister to them, and that together with the family Lumbriculidae they all constitute a clade within Oligochaeta. Results support synonymy of the classes Clitellata and the more commonly used Oligochaeta. Leeches branchiobdellidans, and acanthobdellidans should be regarded as orders equal to their closest relatives, the order Lumbriculida.     

Preliminary investigations of hybridization/reticulate evolution in Guaranidrilus (Enchytraeidae: Oligochaeta)

The identification of gut diverticula at 7/8 as a synapomorphy and recognition of all taxa of Guaranidrilus has been obscured by losses of gut diverticula within the lineage. The homoplastic occurrence of basally unpaired peptonephridia in some enchytraeid species has similarly obscured the limits of Hemienchytraeus. Taxa with unpredictable relationships, morphogenic irregularities in some reproductive structures, and, apparently, modified modes of reproduction, suggest the possibilities of hybridization between taxa with both close and distant relationships.     

Bradykinin is degraded in hypoxic lungs and does not affect epithelial permeability

To investigate the effect of intravenous infusions of bradykinin (BK) on the permeability of the hypoxic pulmonary epithelium to small solutes, experiments (n = 7) were performed in yearling sheep with chronic vascular catheters. Sheep were anesthetized, intubated, paralyzed, and ventilated. After establishing stable and normal base-line pulmonary hemodynamics and blood gas tensions, the lungs were insufflated with a submicronic aerosol of technetium-99m-labeled diethylenetriaminepentaacetate (99mTc-DTPA, mol wt = 492). Radioactivity arising from the right hemithorax was measured by an NaI probe with a parallel-holed collimator. The base-line pulmonary clearance rate (k) for 99mTc-DTPA was 0.51 +/- 0.09% (SE)/min, while the sheep were ventilated with a fractional concentration of inspired O2 (FIO2) of 0.5 [arterial partial pressure of O2 (PaO2) = 196 +/- 11.4 (SE) Torr]. Clearance of 99mTc-DTPA was unaffected by hypoxia alone or BK infusions in nonhypoxic lungs. The combination of an intravenous infusion of BK at either 1.2 (n = 3) or 2.4 micrograms . kg-1 . min-1 (n = 4) and alveolar hypoxia [FIO2 = 0.11, PaO2 = 28 +/- 1.6 (SE) Torr] did not affect pulmonary clearance of 99mTc-DTPA [k = 0.43 +/- 0.08% (SE)/min]. In contrast, a 0.05-ml/kg intravenous infusion of oleic acid increased clearance 10-fold in one sheep. During combined hypoxia and BK infusion the pulmonary arterial BK concentration (radioimmunoassay) increased from 0.82 +/- 0.16 (SE) to 7.05 +/- 1.86 ng/ml (P less than 0.001), but the systemic arterial concentrations were unchanged [0.67 +/- 0.19 (SE) to 0.66 +/- 0.09 ng/ml].(ABSTRACT TRUNCATED AT 250 WORDS)     

A very low dead space pneumotachograph for ventilatory measurements in newborns

In premature and full-term neonates, technical limitations hamper the measurements of pulmonary mechanics. Current commercially available pneumotachographs (PNT) either increase the dead space, causing hyperventilation, or increase resistance, thus altering the mechanics of breathing. We modified a previously described low dead space PNT for infants to increase the linear range and frequency response. The mean resistance of the new PNT was 2.44 cmH2O.1-1.s compared with 2.65 cmH2O.1-1.s for the Fleisch no. 0 PNT. The added dead space over the standard endotracheal connector was 0.6 ml compared with 4.7 ml for the Fleisch PNT. Like the Fleisch PNT, the flow resistance was linear from 0 to 15 l/min. In response to a sinusoidal waveform, the new PNT had a phase angle of 21 degrees at 5 Hz and 50 degrees at 16 Hz compared with 19 degrees and 43 degrees, respectively, for the Fleisch PNT. The change in attenuation for both systems was zero until 20 Hz. In summary, the new PNT is lightweight and provides accuracy and low resistance with a very small dead space.     

Secukinumab provides sustained PASDAS-defined remission in psoriatic arthritis and improves health-related quality of life in patients achieving remission: 2-year results from the phase III FUTURE 2 study

Background

Secukinumab has demonstrated sustained improvement in the signs and symptoms of psoriatic arthritis (PsA) over 2?years in the FUTURE 2 study (NCT01752634). This post hoc analysis assessed the ability of secukinumab to achieve Psoriatic Arthritis Disease Activity Score (PASDAS)-based remission or low disease activity (LDA) through 2?years among patients with PsA in the FUTURE 2 study.

Methods

PASDAS (cut-off scores: remission ≤?1.9; LDA >?1.9 and?<?3.2; Moderate Disease Activity ≥?3.2 and?<?5.4; and high disease activity [HDA]?≥?5.4) was assessed in the overall population (tumour necrosis factor inhibitor [TNFi]-naïve and TNFi-experienced), in patients stratified by prior TNFi use and by disease duration at weeks 16, 52 and 104. The impact of secukinumab on individual PASDAS core components and on the relationship between PASDAS states and patient-reported outcomes (PROs), including physical function, health-related quality of life (HRQoL) and work productivity, were also assessed. Data for the approved doses of secukinumab (300 and 150?mg) are reported. PASDAS scores and core components were reported as observed, and PROs were analysed using mixed models for repeated measures.

Results

In the overall population, PASDAS remission and LDA were achieved in 15.6% and 22.9%, respectively, of patients treated with secukinumab 300?mg and in 15.2% and 19.2%, respectively, in the secukinumab 150?mg group versus 2.3% and 13.8%, respectively, with placebo at week 16. In the TNFi-naïve group, a higher proportion of patients achieved remission?+?LDA at week 16 with secukinumab 300 and 150?mg (46.2% and 42.9%, respectively) versus placebo (17.5%), with corresponding responses in TNFi-experienced patients being 22.6% and 19.4% versus 13.3%. Remission/LDA responses with secukinumab were sustained through 2?years. Patients achieving remission/LDA reported greater improvements in PROs than patients in HDA through 2?years.

Conclusions

Secukinumab-treated patients achieved higher PASDAS-defined remissions or LDA compared with placebo at week 16, which were sustained through 2?years. Remission/LDA was achieved by both TNFi-naïve and TNFi-experienced patients treated with secukinumab, with higher rates in TNFi-naïve patients. Secukinumab-treated patients achieving remission/LDA reported significantly greater improvements in PROs, including physical function and different dimensions of health-related quality of life and work, than patients in HDA.

Trial registration

ClinicalTrials.gov, NCT01752634. Registered on December 19, 2012.EUDRACT, 2012-004439-22. Registered on December 12, 2012.