The last decade has spawned an exciting new era of oncotherapy in dermatology, including the development of targeted therapies for metastatic melanoma and basal cell carcinoma. Along with skin ...cancer, deregulation of the PI3K-AKT-mTOR and RAS-RAF-MEK-ERK intracellular signaling pathways contributes to tumorigenesis of a multitude of other cancers, and inhibitors of these pathways are being actively studied. Similar to other classes of targeted therapies, cutaneous adverse effects are among the most frequent toxicities observed with mitogen-activated protein kinase pathway inhibitors, PI3K-AKT-mTOR inhibitors, hedgehog signaling pathway inhibitors, and immunotherapies. Given the rapid expansion of these families of targeted treatments, dermatologists will be essential in offering dermatologic supportive care measures to cancer patients being treated with these agents. Part II of this continuing medical education article reviews skin-related adverse sequelae, including the frequency of occurrence and the implications associated with on- and off-target cutaneous toxicities of inhibitors of the RAS-RAF-MEK-ERK pathway, PI3K-AKT-mTOR pathway, hedgehog signaling pathway, and immunotherapies.
Load Induced Blindness Macdonald, James S. P; Lavie, Nilli
Journal of experimental psychology. Human perception and performance,
10/2008, Letnik:
34, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied on indirect measures ...that infer perception from distractor effects on reaction times or neural activity (see
N. Lavie, 2005
, for a review). Here we varied the level of perceptual load in a letter-search task and assessed its effect on the conscious perception of a search-irrelevant shape stimulus appearing in the periphery, using a direct measure of awareness (present/absent reports). Detection sensitivity (
d`
) was consistently reduced with high, compared to low, perceptual load but was unaffected by the level of working memory load. Because alternative accounts in terms of expectation, memory, response bias, and goal-neglect due to the more strenuous high load task were ruled out, these experiments clearly demonstrate that high perceptual load determines conscious perception, impairing the ability to merely detect the presence of a stimulus-a phenomenon of load induced blindness.
Native cell-free transcription–translation systems offer a rapid route to characterize the regulatory elements (promoters, transcription factors) for gene expression from nonmodel microbial hosts, ...which can be difficult to assess through traditional in vivo approaches. One such host, Bacillus megaterium, is a giant Gram-positive bacterium with potential biotechnology applications, although many of its regulatory elements remain uncharacterized. Here, we have developed a rapid automated platform for measuring and modeling in vitro cell-free reactions and have applied this to B. megaterium to quantify a range of ribosome binding site variants and previously uncharacterized endogenous constitutive and inducible promoters. To provide quantitative models for cell-free systems, we have also applied a Bayesian approach to infer ordinary differential equation model parameters by simultaneously using time-course data from multiple experimental conditions. Using this modeling framework, we were able to infer previously unknown transcription factor binding affinities and quantify the sharing of cell-free transcription–translation resources (energy, ribosomes, RNA polymerases, nucleotides, and amino acids) using a promoter competition experiment. This allows insights into resource limiting-factors in batch cell-free synthesis mode. Our combined automated and modeling platform allows for the rapid acquisition and model-based analysis of cell-free transcription–translation data from uncharacterized microbial cell hosts, as well as resource competition within cell-free systems, which potentially can be applied to a range of cell-free synthetic biology and biotechnology applications.
The retinoblastoma tumor suppressor protein (RB) plays an important role in biological processes such as cell cycle control, DNA damage repair, epigenetic regulation, and genome stability. The ...canonical model of RB regulation is that cyclin-CDKs phosphorylate and render RB inactive in late G1/S, promoting entry into S phase. Recently, monophosphorylated RB species were described to have distinct cell-cycle-independent functions, suggesting that a phosphorylation code dictates diversity of RB function. However, a biologically relevant, functional role of RB phosphorylation at non-CDK sites has remained elusive. Here, we investigated S838/T841 dual phosphorylation, its upstream stimulus, and downstream functional output. We found that mimicking T-cell receptor activation in Jurkat leukemia cells induced sequential activation of downstream kinases including p38 MAPK and RB S838/T841 phosphorylation. This signaling pathway disrupts RB and condensin II interaction with chromatin. Using cells expressing a WT or S838A/T841A mutant RB fragment, we present evidence that deficiency for this phosphorylation event prevents condensin II release from chromatin.
J. Neurochem. (2009) 112, 882-899. Ectopic expression of the TrkA receptor tyrosine kinase in tumors of the nervous system can mediate nerve growth factor (NGF)-dependent cell death by apoptosis and .../or autophagy. Herein, we demonstrate that TrkA can also induce cell death in medulloblastoma Daoy cells by a caspase-independent mechanism that involves the hyperstimulation of macropinocytosis. Specifically, NGF-stimulates the uptake of AlexaFluor546-dextran into lysosome-associated membrane protein-1 positive vacuoles which fuse with microtubule associated protein light chain 3 (LC3) positive autophagosomes, to form large intracellular vacuoles (> 1 μm), which then fuse with lysotracker positive lysosomes. While LC3 cleavage and the appearance of LC3 positive vacuoles suggest the induction of autophagy, siRNA reduced expression of four proteins essential to autophagy (beclin-1, Atg5, LC3 and Atg9) neither blocks NGF-induced vacuole formation nor cell death. TrkA activated cell death does not require p38, JNK or Erk1/2 kinases but does require activation of class III PI-3 kinase and is blocked by the casein kinase 1 (CK1) inhibitor, D4476. This inhibitor does not interfere with TrkA activation but does block NGF-dependent AlexaFluor546-dextran uptake and CK1 dependent phosphorylation of β-catenin. Collectively, these data demonstrate that TrkA stimulates cell death by a novel mechanism involving CK1-dependent hyperstimulation of macropinocytosis.
Embryonal rhabdomyosarcoma (ERMS) is the most common soft tissue cancer in children. The prognosis of patients with relapsed or metastatic disease remains poor. ERMS genomes show few recurrent ...mutations, suggesting that other molecular mechanisms such as epigenetic regulation might play a major role in driving ERMS tumor biology. In this study, we have demonstrated the diverse roles of histone deacetylases (HDACs) in the pathogenesis of ERMS by characterizing effects of HDAC inhibitors, trichostatin A (TSA) and suberoylanilide hydroxamic acid (SAHA; also known as vorinostat) in vitro and in vivo. TSA and SAHA suppress ERMS tumor growth and progression by inducing myogenic differentiation as well as reducing the self-renewal and migratory capacity of ERMS cells. Differential expression profiling and pathway analysis revealed downregulation of key oncogenic pathways upon HDAC inhibitor treatment. By gain-of-function, loss-of-function, and chromatin immunoprecipitation (ChIP) studies, we show that Notch1- and EphrinB1-mediated pathways are regulated by HDACs to inhibit differentiation and enhance migratory capacity of ERMS cells, respectively. Our study demonstrates that aberrant HDAC activity plays a major role in ERMS pathogenesis. Druggable targets in the molecular pathways affected by HDAC inhibitors represent novel therapeutic options for ERMS patients.
Variability in the detection and discrimination of weak visual stimuli has been linked to oscillatory neural activity. In particular, the amplitude of activity in the alpha-band (8–12 Hz) has been ...shown to impact the objective likelihood of stimulus detection, as well as measures of subjective visibility, attention, and decision confidence. Here we investigate how preparatory alpha in a cued pretarget interval influences performance and phenomenology, by recording simultaneous subjective measures of attention and confidence (experiment 1) or attention and visibility (experiment 2) on a trial-by-trial basis in a visual detection task. Across both experiments, alpha amplitude was negatively and linearly correlated with the intensity of subjective attention. In contrast with this linear relationship, we observed a quadratic relationship between the strength of alpha oscillations and subjective ratings of confidence and visibility. We find that this same quadratic relationship links alpha amplitude with the strength of stimulus-evoked responses. Visibility and confidence judgments also corresponded with the strength of evoked responses, but confidence, uniquely, incorporated information about attentional state. As such, our findings reveal distinct psychological and neural correlates of metacognitive judgments of attentional state, stimulus visibility, and decision confidence when these judgments are preceded by a cued target interval.
Cell-free transcription-translation systems were originally applied towards in vitro protein production. More recently, synthetic biology is enabling these systems to be used within a systematic ...design context for prototyping DNA regulatory elements, genetic logic circuits and biosynthetic pathways. The Gram-positive soil bacterium, Bacillus subtilis, is an established model organism of industrial importance. To this end, we developed several B. subtilis-based cell-free systems. Our improved B. subtilis WB800N-based system was capable of producing 0.8µM GFP, which gave a ~72x fold-improvement when compared with a B. subtilis 168 cell-free system. Our improved system was applied towards the prototyping of a B. subtilis promoter library in which we engineered several promoters, derived from the wild-type Pgrac (σA) promoter, that display a range of comparable in vitro and in vivo transcriptional activities. Additionally, we demonstrate the cell-free characterisation of an inducible expression system, and the activity of a model enzyme - renilla luciferase.
•Several B. subtilis cell-free transcription-translation systems have been developed.•B. subtilis WB800N cell-free system ~72× more active than B. subtilis 168 system.•Comparability between in vitro and in vivo characterised regulatory elements.•Characterised an inducible expression system for genetic circuit applications.•Applied to measure the activity of the model enzyme Renilla luciferase.
Plants are a tremendous source of diverse chemicals, including many natural product-derived drugs. It has recently become apparent that the genes for the biosynthesis of numerous different types of ...plant natural products are organized as metabolic gene clusters, thereby unveiling a highly unusual form of plant genome architecture and offering novel avenues for discovery and exploitation of plant specialized metabolism. Here we show that these clustered pathways are characterized by distinct chromatin signatures of histone 3 lysine trimethylation (H3K27me3) and histone 2 variant H2A.Z, associated with cluster repression and activation, respectively, and represent discrete windows of co-regulation in the genome. We further demonstrate that knowledge of these chromatin signatures along with chromatin mutants can be used to mine genomes for cluster discovery. The roles of H3K27me3 and H2A.Z in repression and activation of single genes in plants are well known. However, our discovery of highly localized operon-like co-regulated regions of chromatin modification is unprecedented in plants. Our findings raise intriguing parallels with groups of physically linked multi-gene complexes in animals and with clustered pathways for specialized metabolism in filamentous fungi.
Tracking the Consolidation of U.S. Agriculture MacDonald, James M.
Applied economic perspectives and policy,
September 2020, 2020-09-00, 20200901, Letnik:
42, Številka:
3
Journal Article
Recenzirano
I assess farm sector consolidation in the United States from the 1980s through the most recent (2017) Census of Agriculture. Consolidation has been large, widespread across crop and livestock ...commodities, and persistent over time. Research on this topic benefits from access to farm‐level datasets, which provide more comprehensive insights into consolidation and alter what we thought we knew about farm consolidation in earlier studies using aggregated data. I close with a reflection on the applications and challenges that I have found in using firm‐, plant‐, and transactions‐level microdata through my career.
PDF
