3,718 research outputs found
Qualitative Perspectives toward Relational Connection in Pastoral Ministry
We present the results of a phenomenological, qualitative research study in which 13 Southern Baptist (SB) pastors were administered in-depth interviews. The sample was selected from a total of 37 exemplars, identified in the quantitative component of a larger mixed-methods study, regarding the pastorsâ perspectives toward relational connection in pastoral ministry. Three themes emerged from the data regarding relational connection in pastoral ministry. First, pastors indicated the need to be intentional about pastoral connection. Second, the pastors stressed the importance of being available to congregants who specifically desire pastoral connection. Finally, the participants related that pastors should give particular attention to connections with lay church leaders
Mixed Messages: How Bacteria Resolve Conflicting Signals
An elegant new study by Bollenbach and Kishony (2011) in this issue of Molecular Cell shows how bacteria resolve the apparent conflicts created when they face two signals with opposite effects on gene expression
Diving Into Infographics: Research Skills for Early Undergraduates in Global Environmental Science
The common experience for many early undergraduate students is to be taught
the basics of their field via a survey course. Most often, their introduction to
the library and librarians might be a one-hour instructional session on how to
use the library catalog and find books and articles. Studentsâ understanding of
research and the library remains unchanged from their prior knowledge: sub-
ject information comes from teachers and textbooks, and libraries are places
to study and check out books. This chapter describes a course that attempts to
re-envision this relationship by giving students an initial experience that is a
dive into the research process in a manageable format, with a semester-long in-
troduction to their field, to research, and the role of the academic librarian as a
research partner
Rate of environmental change determines stress response specificity
Cells use general stress response pathways to activate diverse target genes in response to a variety of stresses. However, general stress responses coexist with more specific pathways that are activated by individual stresses, provoking the fundamental question of whether and how cells control the generality or specificity of their response to a particular stress. Here we address this issue using quantitative time-lapse microscopy of the Bacillus subtilis environmental stress response, mediated by Ï^B. We analyzed Ï^B activation in response to stresses such as salt and ethanol imposed at varying rates of increase. Dynamically, Ï^B responded to these stresses with a single adaptive activity pulse, whose amplitude depended on the rate at which the stress increased. This rate-responsive behavior can be understood from mathematical modeling of a key negative feedback loop in the underlying regulatory circuit. Using RNAseq we analyzed the effects of both rapid and gradual increases of ethanol and salt stress across the genome. Because of the rate responsiveness of Ï^B activation, salt and ethanol regulons overlap under rapid, but not gradual, increases in stress. Thus, the cell responds specifically to individual stresses that appear gradually, while using Ï^B to broaden the cellular response under more rapidly deteriorating conditions. Such dynamic control of specificity could be a critical function of other general stress response pathways
Accurate prediction of gene feedback circuit behavior from component properties
A basic assumption underlying synthetic biology is that analysis of genetic circuit elements, such as regulatory proteins and promoters, can be used to understand and predict the behavior of circuits containing those elements. To test this assumption, we used timeâlapse fluorescence microscopy to quantitatively analyze two autoregulatory negative feedback circuits. By measuring the gene regulation functions of the corresponding repressorâpromoter interactions, we accurately predicted the expression level of the autoregulatory feedback loops, in molecular units. This demonstration that quantitative characterization of regulatory elements can predict the behavior of genetic circuits supports a fundamental requirement of synthetic biology
Lattice QCD Evidence that the Lambda(1405) Resonance is an Antikaon-Nucleon Molecule
For almost 50 years the structure of the Lambda(1405) resonance has been a
mystery. Even though it contains a heavy strange quark and has odd parity, its
mass is lower than any other excited spin-1/2 baryon. Dalitz and co-workers
speculated that it might be a molecular state of an antikaon bound to a
nucleon. However, a standard quark-model structure is also admissible. Although
the intervening years have seen considerable effort, there has been no
convincing resolution. Here we present a new lattice QCD simulation showing
that the strange magnetic form factor of the Lambda(1405) vanishes, signaling
the formation of an antikaon-nucleon molecule. Together with a Hamiltonian
effective-field-theory model analysis of the lattice QCD energy levels, this
strongly suggests that the structure is dominated by a bound antikaon-nucleon
component. This result clarifies that not all states occurring in nature can be
described within a simple quark model framework and points to the existence of
exotic molecular meson-nucleon bound states.Comment: Manuscript accepted for publication. 4 figures, 5 page
DVC interneuron cGAL driver in Caenorhabditis elegans
cGAL, a recently developed temperature-robust bipartite GAL4-UAS system in C. elegans, consists of two components: a cGAL âdriverâ that expresses the cGAL protein in specific cells using a promoter (i.e. neuron-specific or tissue-specific), and an âeffectorâ that carries a gene of interest downstream of UAS (Wang et al., 2017). Crossing or combining a driver with an effector leads to the expression of the gene of interest in a cell-specific or tissue-specific manner.
Here we report a new cGAL driver for the DVC interneuron. The ceh-63 promoter was chosen due to its restricted expression in the DVC neuron (Feng et al. 2012). The DVC interneuron driver construct containing the ceh-63 promoter (646 bp upstream of ATG translation start site) was injected into N2 and an integrated DVC driver line was generated. When crossed with the UAS-GFP effector strain (PS6843), the ceh-63 cGAL driver dictated GFP expression in the single DVC neuron (Figure 1), in addition to GFP in the coelomocyte from Punc-122::gfp co-injection marker. We did not observe GFP expression in uterus as reported by Feng et al., 2012
DVC interneuron cGAL driver in Caenorhabditis elegans
cGAL, a recently developed temperature-robust bipartite GAL4-UAS system in C. elegans, consists of two components: a cGAL âdriverâ that expresses the cGAL protein in specific cells using a promoter (i.e. neuron-specific or tissue-specific), and an âeffectorâ that carries a gene of interest downstream of UAS (Wang et al., 2017). Crossing or combining a driver with an effector leads to the expression of the gene of interest in a cell-specific or tissue-specific manner.
Here we report a new cGAL driver for the DVC interneuron. The ceh-63 promoter was chosen due to its restricted expression in the DVC neuron (Feng et al. 2012). The DVC interneuron driver construct containing the ceh-63 promoter (646 bp upstream of ATG translation start site) was injected into N2 and an integrated DVC driver line was generated. When crossed with the UAS-GFP effector strain (PS6843), the ceh-63 cGAL driver dictated GFP expression in the single DVC neuron (Figure 1), in addition to GFP in the coelomocyte from Punc-122::gfp co-injection marker. We did not observe GFP expression in uterus as reported by Feng et al., 2012
Stochastic Pulse Regulation in Bacterial Stress Response
Gene regulatory circuits can use dynamic, and even stochastic, strategies to respond to environmental conditions. We examined activation of the general stress response mediated by the alternative sigma factor, Ï^B, in individual Bacillus subtilis cells. We observed that energy stress activates Ï^B in discrete stochastic pulses, with increasing levels of stress leading to higher pulse frequencies. By perturbing and rewiring the endogenous system, we found that this behavior results from three key features of the Ï^B circuit: an ultrasensitive phosphorylation switch; stochasticity (ânoiseâ), which activates that switch; and a mixed (positive and negative) transcriptional feedback, which can both amplify a pulse and switch it off. Together, these results show how prokaryotes encode signals using stochastic pulse frequency modulation through a compact regulatory architecture
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