THE GREEN PHENOTYPE OF ARABIDOPSIS THALIANA CELL CULTURES IS INSENSITIVE TO SUCROSE CONCENTRATIONS

Plant cell cultures are typically grown in media supplemented with 3% (w/v) sucrose and exhibit a non-green phenotype. I show that Arabidopsis thaliana cell cultures remain green even at 15% (w/v) sucrose when grown in the light and exhibit the major constituents of a normal photosynthetic apparatus. However, growth in the light was inhibited when no exogenous carbon source was provided. Gas exchange measurements indicated that rates of photosynthesis never exceeded rates of respiration. Thus, these green cells grow below their light compensation points. However, increasing sucrose concentration from 3% to 15% (w/v) decreased both photosynthetic efficiency and capacity. Furthermore, the green cells exhibit reversible photoacclimation. Energy partitioning measured by chlorophyll a fluorescence indicates that a large portion of the light energy absorbed is dissipated by both antennae and constitutive quenching mechanisms. The results are discussed in terms of sucrose sensing and its role in remodeling of the photosynthetic apparatus

Quantitative analysis of acetyl-CoA production in hypoxic cancer cells reveals substantial contribution from acetate

Background Cell growth requires fatty acids for membrane synthesis. Fatty acids are assembled from 2-carbon units in the form of acetyl-CoA (AcCoA). In nutrient and oxygen replete conditions, acetyl-CoA is predominantly derived from glucose. In hypoxia, however, flux from glucose to acetyl-CoA decreases, and the fractional contribution of glutamine to acetyl-CoA increases. The significance of other acetyl-CoA sources, however, has not been rigorously evaluated. Here we investigate quantitatively, using 13C-tracers and mass spectrometry, the sources of acetyl-CoA in hypoxia.<p></p> Results In normoxic conditions, cultured cells produced more than 90% of acetyl-CoA from glucose and glutamine-derived carbon. In hypoxic cells, this contribution dropped, ranging across cell lines from 50% to 80%. Thus, under hypoxia, one or more additional substrates significantly contribute to acetyl-CoA production. 13C-tracer experiments revealed that neither amino acids nor fatty acids are the primary source of this acetyl-CoA. Instead, the main additional source is acetate. A large contribution from acetate occurs despite it being present in the medium at a low concentration (50–500 μM).<p></p> Conclusions Acetate is an important source of acetyl-CoA in hypoxia. Inhibition of acetate metabolism may impair tumor growth.<p></p&gt

A surgical treatment for anxiety-triggered palmar hyperhidrosis is not unlike treating tearfulness in major depression by severing the nerves to the lacrimal glands

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Evidence-Based Interventions that Promote Resident Wellness from the Council of Emergency Residency Directors

Initiatives for addressing resident wellness are a recent requirement of the Accreditation Council for Graduate Medical Education in response to high rates of resident burnout nationally. We review the literature on wellness and burnout in residency education with a focus on assessment, individual-level interventions, and systemic or organizational interventions

Work group inclusion : test of a scale and model

We develop a theoretically based 10-item measure of work group inclusion comprised of two components (belongingness and uniqueness) and use this measure to empirically test the nomological network of work group inclusion developed by Shore et al. In Phase 1, we use two samples of full-time employees to develop and refine items as well as establish content validity. In Phase 2, we demonstrate convergent, discriminant, and incremental validity with both conceptually related and unrelated constructs. In Phase 3, we use data from an additional sample of employees and supervisors to test criterion-related validity and mediation by examining the multilevel relationships between inclusion and important antecedents and outcomes. Across the three phases of our study, the results demonstrate support not only for the factor structure, reliability, and validity of our work group inclusion measure but also for a theoretical model in which the construct of inclusion has important implications for individuals and organizations

The Locus Ceruleus in PTSD

NO ABSTRACT: This is 750 word encyclopedia entr

Inclusive leadership : realizing positive outcomes through belongingness and being valued for uniqueness

We introduce a theoretically-grounded conceptualization of inclusive leadership and present a framework for understanding factors that contribute to and follow from inclusive leadership within work groups. We conceptualize inclusive leadership as a set of positive leader behaviors that facilitate group members perceiving belongingness in the work group while maintaining their uniqueness within the group as they fully contribute to group processes and outcomes. We propose that leader pro-diversity beliefs, humility, and cognitive complexity increase the propensity of inclusive leader behaviors. We identify five categories of inclusive leadership behaviors that facilitate group members' perceptions of inclusion, which in turn lead to member work group identification, psychological empowerment, and behavioral outcomes (creativity, job performance, and reduced turnover) in the pursuit of group goals. This framework provides theoretical grounding for the construct of inclusive leadership while advancing our understanding of how leaders can increase diverse work group effectiveness

Facilitating recombinase discovery in non-standard model organisms

Diverse research into the model organism, Escherichia coli, has added substantial depth to our understanding of genome editing of bacteria. Recombineering using the λ Red system is the most disruptive molecular technology discovered thus far, and improved our ability to introduce targeted single nucleotide variants by ~1E4 fold. This discovery has catalyzed incredible progress and enabled ambitious genome/organism engineering projects such as high throughput metabolic engineering to genome-wide codon reassignment. While efforts in E. coli have since accelerated further, work in other bacterial model organisms has lacked this catalyst and continues to fall behind E. coli. To facilitate development of disruptive technologies for non-standard model organisms, we produced a library of homologs to the λ Red recombinase, λ β (NP_040617.1), to generate a toolbox for recombinase discovery in organisms with minimal tools. We demonstrated the recombinase discovery workflow, called Serial Evolutionary Enrichment for Recombinases (SEER), in E. coli and present a number of alternatives to using λ Red for genome editing. We then moved on to explore λ β-mediated recombination in vitro where we able to show that bet specifically unloads E. coli Ssb from Ssb-coated oligos to facilitate annealing. We hypothesized that ssb represents the minimal host interaction node that a recombinase must achieve to facilitate recombination in vivo, and demonstrated a gain-of-function phenotype when species-matched recombinase/ssb pairs are ported into foreign organisms, potentially opening up poorly understood organisms to recombineering using well understood recombinase/ssb pairs

3-Dimensional Tuning of an Atomically Defined Silicon Tunnel Junction

A requirement for quantum information processors is the in-situ tunability of the tunnel rates and the exchange interaction energy within the device. The large energy level separation for atom qubits in silicon is well suited for qubit operation but limits device tunability using in-plane gate architectures, requiring vertically separated top-gates to control tunnelling within the device. In this paper we address control of the simplest tunnelling device in Si:P, the tunnel junction. Here we demonstrate that we can tune its conductance by using a vertically separated top-gate aligned with +-5nm precision to the junction. We show that a monolithic 3D epitaxial top-gate increases the capacitive coupling by a factor of 3 compared to in-plane gates, resulting in a tunnel barrier height tunability of 0-186meV. By combining multiple gated junctions in series we extend our monolithic 3D gating technology to implement nanoscale logic circuits including AND and OR gates