941 research outputs found

    PrimPol bypasses UV photoproducts during eukaryotic chromosomal DNA replication

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    DNA damage can stall the DNA replication machinery, leading to genomic instability. Thus, numerous mechanisms exist to complete genome duplication in the absence of a pristine DNA template, but identification of the enzymes involved remains incomplete. Here, we establish that Primase-Polymerase (PrimPol; CCDC111), an archaeal-eukaryotic primase (AEP) in eukaryotic cells, is involved in chromosomal DNA replication. PrimPol is required for replication fork progression on ultraviolet (UV) lightdamaged DNA templates, possibly mediated by its ability to catalyze translesion synthesis (TLS) of these lesions. This PrimPol UV lesion bypass pathway is not epistatic with the Pol h-dependent pathway and, as a consequence, protects xeroderma pigmentosum variant (XP-V) patient cells from UV-induced cytotoxicity. In addition, we establish that PrimPol is also required for efficient replication fork progression during an unperturbed S phase. These and other findings indicate that PrimPol is an important player in replication fork progression in eukaryotic cells

    Characterization of 81P/Wild 2 Particles C2067,1,111,6.0 and C2067,1,111,8.0

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    The concentrations of C and N in cometary particles are of interest in characterizing the regions where comets formed. One aim of this work is to analyze enough Stardust particles to draw meaningful statistical conclusions about their inventories of C and N. Toward that end we report recent studies of Stardust particles and related materials

    Preclinical Evaluation of AZ12601011 and AZ12799734, Inhibitors of Transforming Growth Factor β Superfamily Type 1 Receptors.

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    The transforming growth factor β (TGFβ) superfamily includes TGFβ, activins, inhibins, and bone morphogenetic proteins (BMPs). These extracellular ligands have essential roles in normal tissue homeostasis by coordinately regulating cell proliferation, differentiation, and migration. Aberrant signaling of superfamily members, however, is associated with fibrosis as well as tumorigenesis, cancer progression, metastasis, and drug-resistance mechanisms in a variety of cancer subtypes. Given their involvement in human disease, the identification of novel selective inhibitors of TGFβ superfamily receptors is an attractive therapeutic approach. Seven mammalian type 1 receptors have been identified that have context-specific roles depending on the ligand and the complex formation with the type 2 receptor. Here, we characterize the biologic effects of two transforming growth factor β receptor 1 (TGFBR1) kinase inhibitors designed to target TGFβ signaling. AZ12601011 [2-(2-pyridinyl)-4-(1H-pyrrolo[3,2-c]pyridin-1-yl)-6,7-dihydro-5H-cyclopenta[d]pyrimidine]; structure previously undisclosed] and AZ12799734 [4-({4-[(2,6-dimethyl-3-pyridinyl)oxy]-2-pyridinyl}amino)benzenesulfonamide] (IC50 = 18 and 47 nM, respectively) were more effective inhibitors of TGFβ-induced reporter activity than SB-431542 [4-[4-(1,3-benzodioxol-5-yl)-5-(2-pyridinyl)-1H-imidazol-2-yl]benzamide] (IC50 = 84 nM) and LY2157299 [4-[2-(6-methylpyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazol-3-yl]quinoline-6-carboxamide monohydrate]] (galunisertib) (IC50 = 380 nM). AZ12601011 inhibited phosphorylation of SMAD2 via the type 1 receptors activin A receptor type 1B (ALK4), TGFBR1, and activin A receptor type 1C (ALK7). AZ12799734, however, is a pan TGF/BMP inhibitor, inhibiting receptor-mediated phosphorylation of SMAD1 by activin A receptor type 1L, bone morphogenetic protein receptor type 1A, and bone morphogenetic protein receptor type 1B and phosphorylation of SMAD2 by ALK4, TGFBR1, and ALK7. AZ12601011 was highly effective at inhibiting basal and TGFβ-induced migration of HaCaT keratinocytes and, furthermore, inhibited tumor growth and metastasis to the lungs in a 4T1 syngeneic orthotopic mammary tumor model. These inhibitors provide new reagents for investigating in vitro and in vivo pathogenic processes and the contribution of TGFβ- and BMP-regulated signaling pathways to disease states

    An Investigation into the Cognition Behind Spontaneous String Pulling in New Caledonian Crows

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    The ability of some bird species to pull up meat hung on a string is a famous example of spontaneous animal problem solving. The “insight” hypothesis claims that this complex behaviour is based on cognitive abilities such as mental scenario building and imagination. An operant conditioning account, in contrast, would claim that this spontaneity is due to each action in string pulling being reinforced by the meat moving closer and remaining closer to the bird on the perch. We presented experienced and naïve New Caledonian crows with a novel, visually restricted string-pulling problem that reduced the quality of visual feedback during string pulling. Experienced crows solved this problem with reduced efficiency and increased errors compared to their performance in standard string pulling. Naïve crows either failed or solved the problem by trial and error learning. However, when visual feedback was available via a mirror mounted next to the apparatus, two naïve crows were able to perform at the same level as the experienced group. Our results raise the possibility that spontaneous string pulling in New Caledonian crows may not be based on insight but on operant conditioning mediated by a perceptual-motor feedback cycle

    Psychological determinants of whole-body endurance performance

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    Background: No literature reviews have systematically identified and evaluated research on the psychological determinants of endurance performance, and sport psychology performance-enhancement guidelines for endurance sports are not founded on a systematic appraisal of endurance-specific research. Objective: A systematic literature review was conducted to identify practical psychological interventions that improve endurance performance and to identify additional psychological factors that affect endurance performance. Additional objectives were to evaluate the research practices of included studies, to suggest theoretical and applied implications, and to guide future research. Methods: Electronic databases, forward-citation searches, and manual searches of reference lists were used to locate relevant studies. Peer-reviewed studies were included when they chose an experimental or quasi-experimental research design, a psychological manipulation, endurance performance as the dependent variable, and athletes or physically-active, healthy adults as participants. Results: Consistent support was found for using imagery, self-talk, and goal setting to improve endurance performance, but it is unclear whether learning multiple psychological skills is more beneficial than learning one psychological skill. The results also demonstrated that mental fatigue undermines endurance performance, and verbal encouragement and head-to-head competition can have a beneficial effect. Interventions that influenced perception of effort consistently affected endurance performance. Conclusions: Psychological skills training could benefit an endurance athlete. Researchers are encouraged to compare different practical psychological interventions, to examine the effects of these interventions for athletes in competition, and to include a placebo control condition or an alternative control treatment. Researchers are also encouraged to explore additional psychological factors that could have a negative effect on endurance performance. Future research should include psychological mediating variables and moderating variables. Implications for theoretical explanations of endurance performance and evidence-based practice are described

    Entomological Surveillance of Behavioural Resilience and Resistance in Residual Malaria Vector Populations.

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    The most potent malaria vectors rely heavily upon human blood so they are vulnerable to attack with insecticide-treated nets (ITNs) and indoor residual spraying (IRS) within houses. Mosquito taxa that can avoid feeding or resting indoors, or by obtaining blood from animals, mediate a growing proportion of the dwindling transmission that persists as ITNs and IRS are scaled up. Increasing frequency of behavioural evasion traits within persisting residual vector systems usually reflect the successful suppression of the most potent and vulnerable vector taxa by IRS or ITNs, rather than their failure. Many of the commonly observed changes in mosquito behavioural patterns following intervention scale-up may well be explained by modified taxonomic composition and expression of phenotypically plastic behavioural preferences, rather than altered innate preferences of individuals or populations. Detailed review of the contemporary evidence base does not yet provide any clear-cut example of true behavioural resistance and is, therefore, consistent with the hypothesis presented. Caution should be exercised before over-interpreting most existing reports of increased frequency of behavioural traits which enable mosquitoes to evade fatal contact with insecticides: this may simply be the result of suppressing the most behaviourally vulnerable of the vector taxa that constituted the original transmission system. Mosquito taxa which have always exhibited such evasive traits may be more accurately described as behaviourally resilient, rather than resistant. Ongoing national or regional entomological monitoring surveys of physiological susceptibility to insecticides should be supplemented with biologically and epidemiologically meaningfully estimates of malaria vector population dynamics and the behavioural phenotypes that determine intervention impact, in order to design, select, evaluate and optimize the implementation of vector control measures

    Large cell neuroendocrine lung carcinoma: consensus statement from The British Thoracic Oncology Group and the Association of Pulmonary Pathologists

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    Over the past 10 years, lung cancer clinical and translational research has been characterised by exponential progress, exemplified by the introduction of molecularly targeted therapies, immunotherapy and chemo-immunotherapy combinations to stage III and IV non-small cell lung cancer. Along with squamous and small cell lung cancers, large cell neuroendocrine carcinoma (LCNEC) now represents an area of unmet need, particularly hampered by the lack of an encompassing pathological definition that can facilitate real-world and clinical trial progress. The steps we have proposed in this article represent an iterative and rational path forward towards clinical breakthroughs that can be modelled on success in other lung cancer pathologies
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